Customer Ratings & Reviews

PROS: * Very nice quality * Robust app (so many links, videos, stats, and data) * syncs with other health services (i.e. Apple Fit, Fitbit, Garmin) * Easy to use * Comes with an included travel case CONS: * Another subscription service ($19/month or $180/year) * May not separate itself from other smart wearables enough for some If you've come across this product, you might be wondering what it does. I certainly was. According to Lumen, they've created this device to help people improve their metabolic flexibility, which can lead to better workouts, improved sleep, easier weight loss, and an overall happier, longer life. While this may or may not appeal to you, it certainly appeals to me. As a tech lover, I've found that as I age, it takes more effort to maintain my health (I wish it were the other way around). Sleep has always been a challenging aspect for me to manage consistently, so anything that can help me improve my routine is a welcome addition. So far, using the Lumen device has made me more aware of what I eat, how much I move throughout the day, and how I prepare for sleep. I own several health-monitoring devices, including a smartwatch that I wear nearly every day to track my workouts, stress levels, and sleep. Initially, I struggled to see the main differences between the Lumen and my smartwatch in terms of health monitoring. However, with the Lumen, you blow into the device, which provides more detailed information than just your heartbeat. It uses a CO₂ sensor and a flow meter to measure the CO₂ concentration in your breath, offering instant feedback on whether you're burning carbohydrates or fats for energy. This is something a smartwatch currently cannot do. Using the Lumen before workouts or after exercise can help you understand how your body burns fat. Additionally, it provides daily nutritional goals, which can be beneficial for those who struggle with dieting, as many d The presentation of the product is impressive. As soon as you open the box, you can see the quality and care that went into creating it. Priced at $199, it's reasonably priced, but considering its features, the cost may deter some potential buyers. After all, for a little more, you could purchase a nice smartwatch with various health features. On the other hand, the app is well-designed and far from basic. It offers numerous links and a wealth of information and articles to support your health journey, reflecting the careful thought put into the app, much like what you would expect from a membership service. However, this is where some people may lose interest. Yes, there is a subscription for the app and the data collected by the Lumen device. In 2025, many of us are overwhelmed by subscription services and hesitant to add more. I feel the same way. When you consider that a gym membership can cost around $20 a month, it's hard to understand why connecting to an app costs $20 a month (or $180 a year). As with everything, the costs add up. When you factor in the $20 monthly subscription along with the $200 for the device, it becomes quite an investment. However, if you get into it and use it daily, I can see its value. Fortunately, I may not need to stay on top of my health as much as others, so using it daily isn't something I find myself doing. Overall, I'm supportive of technology that helps people maintain their health, and Lumen is certainly doing that. While I may not invest in a membership, it's available for those who will find it helpful daily.

This is more of a hot take of Lumen than a comprehensive review since I’ve only incorporated Lumen into my daily routine for a week. I love the insights smart devices offer about my wellbeing and Lumen is not my first. So, in my experience, weeks of data points are needed before making a conclusion about a device’s worth. And Lumen actually needs a couple weeks use before it’s key metric, the “Flex score,” is revealed. Nonetheless after a week I do have a good feel about Lumen’s usefulness so I’ll discuss my experience with it so far in hopes it can help you decide if it’s a good match for you. Even in just a week I’ve learned a lot about my eating habits and how metabolism works thanks to Lumen. That said since I’m only at the start of this path I can’t yet give it 5 stars. But starting off at 4 is excellent, I think. THE LUMEN DEVICE AND LIFE The Lumen is unlike any other smart health device I own because it’s not passive. Before you purchase the Lumen you have to buy into its lifestyle for it to be useful. The Lumen’s task is to coach you to a healthy, “flexible” fat/carb burning metabolism, or if you’re already there to help maintain it. I was drawn to Lumen because while I think I live and eat healthy I still need help here. I remember the days I could enjoy my favorite treats like bagels and cake and work it off with ease. So, this is an excursion to see if I can get back there to some degree. Lumen determines your metabolic efficiency by analyzing your breath periodically during the day. With either science or sorcery, in almost real time, it calculates whether your metabolism is burning more fat or carbs or a mix of both. It takes that figure, matches it up to the time of day (wake up or bedtime) or activity (pre/post meal or workout) the breath is taken and guides you on what mix of carbs, protein, and fat should be in your diet for the day. When you do a pre-workout baseline breath it will let you know if you need some carbs before starting the workout based on your glycogen level and planned workout. It sounds like an easy process, but my first week was tough because Lumen’s recommendation to me severely reduced my carb intake – of course those are the “good” carbs not the ones that should be always limited. Because Lumen is personal its recommendation to you may be different. Regardless, Lumen is just a tool, like a hammer. Success requires action and commitment to be effective. I say this, having not gone “all in” initially and saw no improvement, why should I. But then I did go buy the book and I’m starting to get positive results. Expect to make lifestyle modifications. That is my overarching takeaway after a week. If you just give it breaths but don’t take its guidance all you are doing is driving hot air into a tube. I say this because it was hard for me to accept its low carb advice and I showed no improvement until I took it seriously. That’s on me. The Lumen itself is a cylinder with a premium feeling metal (but not metallic tasting) mouthpiece on the top and a vent at the bottom. The front has a sleek LED circle to note battery and power status plus, of course, a power button. That’s all there is to it physically. In coordination with the app, it works like a digital spirometer in that you inhale into the device to move a ball to a target in the app. You do this for four “long” seconds, hold your breath for ten more seconds, and the exhale back into the Lumen. At a minimum you must do this at wake up and bedtime, but it’s also helpful to get a reading at other key times like before and after meals or pre and post workout. Without doing this consistently Lumen won’t have enough data to coach you properly and it will also be harder for you to track your progress. The app needs mere seconds to show your current metabolic state represented as a carb:fat burning ratio. There’re five levels with one being mostly fat burning and five being mostly carb burning. The app explains what it means and how to proceed. I don’t perceive the categories to be de facto “healthy” or “unhealthy,” like, for example a BMI number. It’s just where your body is at that moment in time. Metabolism, I’ve learned, changes during the day and night. The goal of the Lumen is to lead you to a “flexible metabolism,” that efficiently burns both fat and carbs but not muscle. And to do that you have to live, what I call, the Lumen life. When it says go low carb, do it even though it’s tough. If you are unwilling the Lumen isn’t going to be a good use of your money. THE APP Like most smart health devices, the center of attention here is the app. Technically it’s free, but its muscle, and therefore the Lumen’s abilities, is only unlocked with a paid subscription service. So, it’s vital to include the cost into your buying decision. Also important, I think, is to read the privacy policy before buying since a lot of personal information is being shared or perhaps “donated.” Similarly, as with other smart health devices, the app attempts to “gamify” the process to make it more engaging. It doesn’t make eating fewer carbs easier, but maybe more mentally rewarding. Generally, it does a good job at this and providing metabolic education. I think it could do a better explaining my specific scores and how that fits into the scale of where I should be. But I have learned a lot about the metabolic process from Lumen. Because metabolism is just one piece of one’s health & fitness puzzle the Lumen app can integrate data from other fitness apps and devices to give you an even clearer analysis. The list of compatible apps is long, so I won’t list them all. If it’s popular it’s probably compatible. I connected my Apple Watch (Apple Fitness and Motion and Health) which shares my sleep and workout information with Lumen. The app has four areas but one is a link to Lumen’s Facebook community and another is generic education on metabolism. The two others are user specific. “Today,” as it sounds is where that day and week’s data is displayed and recorded. You’ll find your breath analysis, daily timeline, and nutrition plan here. If you like you can enter in your meal contents. I’ve always been lazy about meal logging and no change here. But the app tries to ease the inconvenience with the ability to scan UPC codes, detect by photo, or voice log. It’s still a time sink for me, but maybe I’ll get on board. Also, in the app, if you are super dedicated but also busy too, you can order premade meals based on Lumen’s fat and carb recs in app with a week’s notice. Personally, this kind of blatant upsell, especially in a paid-for subscription app, is not my thing and I find distasteful. The other personal section is titled “Me,” and is where you’ll find all your data points over time boiled down to charts and graphs so you can see your progress or not. This is also where the Flex score is posted. LUMEN BOILED DOWN The Lumen is a simple (but smart) device that can help guide you to a health metabolism. But it requires a commitment from the user as well, both in adhering to its sometimes tough eating recommendations and by paying for a pricey subscription. The app is intuitive and presents information and education in an easy-to-understand way. I’ve only been using it for a week but once I started heeding its eating advice I did see metabolic improvement so I’m optimistic that it going to be a fantastic tool to keep me in a more healthy lifestyle, but also to be able to cheat in the future with the ability to burn off a slice of cake now and then a little easier than I now can.

A few years ago, I was diagnosed with Type-2 Diabetes. Fortunately, I’ve been able to manage it quite well by limiting sugar intake along with medications. Since I’ve gotten the A1C level in check, the next step in my health journey is to lose some weight. While the Lumen is not marketed as a weight loss device, my hope is that it will help me with carb awareness and help to encourage me towards better eating habits for the long term. The Lumen device is a very premium-looking piece of technology. It comes in an impressive black box and comes with its own charging stand and travel pouch. The app for Lumen is quite nice, too. Downloading it is the first step in setting it up. The app will guide you through the set up process and train you in how to measure your breath with the device. Lumen does require a subscription ($19/month or $180/year) for ongoing use, but it comes with one month free with the purchase. In a world that seems to have a subscription for nearly everything, I wasn’t surprised about this added expense, but it was disappointing. Since this is a health-tracking device, I would put it in a similar category to something like a gym membership, which requires a monthly fee, but I think it could be lowered quite a bit. As a means of comparison, I’m able to monitor my glucose and track it through an app without an recurring fee. I did have to purchase my glucose monitor, but the app came with no strings attached. So, while I accept there is an ongoing fee for this type of system, I think the cost could be lowered. Using it in practice is somewhat of a feat. First of all, you have to discipline yourself to use it the same time everyday. While having this sort of requirement is helpful for forming good habits, it’s still a hurdle to overcome. Second, the breath capturing process is a little different than I expected. You have to take a slow breath in, hold it for ten seconds, and then exhale slowly. This could be very difficult for some people who have breathing deficiencies. I found it a little difficult at first because the app guides you not to do it to fast or hard. It gives you an on-screen prompt and tells you to keep the ball inside a certain perimeter while you are completing your breathing exercise. It took me a couple of tries to get it just right. So, like I said, discipline is key with this device. For me, I was using Lumen as a supplemental device to help kick start weight loss and monitor my carb burning. I feel that it is helping by providing more information to me, but I question how accurate it is since you have to do the testing ‘just right’ every time you do it. Plus, I was expecting information that was more specific than simply burning fat or carbs. That said, I could see Lumen being very useful for people because the full benefit comes from committing to the daily routines and guidance, not just using the device. Pros: Easy to use Device feels premium App guides your habits Can help drive smarter decisions if you’re looking to optimize energy levels, fat burning, or diet timing. Cons: Requires discipline to make sure you are doing it the same time everyday at the right times for accuracy Device gives you a ‘rough estimate’ of fuel usage, but it’s not as precise as clinical testing (can’t replace that) Not a ‘magic bullet’ for weight loss - could confuse some people expecting that

I was a bit skeptical about the Lumen metabolism tracker device but after about 1 week of use I have found it to be a very useful and promising device for weight loss and/or weight management - I even lost a couple pounds during my first week of use. I love that the app determines your daily macro intake based on your breath measurements and provides suggested meal options as an added bonus. I don't know enough about the science of the Lumen device, but, for me, the breath measurements collected seemed accurate. Additionally, the real time data from the daily measurements boosted my motivation to put in the work each day to meet macro goals. (It was almost like a game to me.) Typically any adjustments to eating habits is tracked by weight loss which doesn't provide instant results to gauge your progress. The measurements taken with the Lumen device allows users to see how their body (metabolism) responds to various situations throughout the day, providing real time results, with a primary focus around meals, workouts, fasting, and your sleep. The device is very easy to use and the Lumen app, after some use, is simple to navigate as well. Another great feature of the app is that it allows for one to connect or sync many health tracking apps. Unfortunately Samsung is not one that can be linked, which is what I use, and that was very disappointing considering that it is a major brand. Most of my experience using the Lumen app went smoothly, but it was a bit buggy at times. There were several times that the search feature for logging meals would freeze and that often resulted in me having to restart the app. There were also a couple days that outages within Google seemed to really affect the functionality of the app too. The barcode scanner for logging meals was surprisingly quick and accurate, and I did try to utilize that often. I was also pleased with the amount of food items already included within the database as well. There are many features with the app that should satisfy most users’ needs. Between the numerous features and the personalized plans the membership fee seems very reasonable. Overall, I have been mostly impressed with the Lumen device and its app. For those looking to try something different, or for those who need more instantaneous progress feedback, the Lumen metabolism tracker just might be the missing piece in your health journey.

I have been using the Lumen breath analyzer for a little over three weeks, and it has already provided some highly useful insights into my metabolism and metabolic health. Inside the box are the Lumen device, a charging stand, a detachable USB-C to A cable for the stand, and a carrying pouch. The cable cannot connect directly to the device to charge, so the Lumen can only be charged with the stand. If traveling, make sure to pack the stand too, and not just the cable. The initial charge took several hours, but after over three weeks of use, the device is displaying 60% battery capacity remaining. The light ring pulses during charging and goes solid once the device is charged. The Lumen works by measuring my breath to determine my metabolic state. The device is simple to use, and the Lumen uses helpful visual and audio prompts to ensure breath is accurately measured during both inhale and exhale. I power on the Lumen, allow the device to warm up. Warm up can take up to thirty seconds but typically takes 10-15 seconds on average. I then follow the app prompts, inhaling through the device to keep he ball within the target circle for four seconds, hold my breath for ten seconds, and exhale back into the device keeping the ball within the target circle for six seconds. If I mess up (for example, exhaling first instead of inhaling) the Lumen will advise and restart the test after a quick pause to allow the device to reset. The Lumen then processes the breath sample and displays my current metabolic state, revealing whether I’m mostly burning carbs, fat, or both. My first result indicated I was burning carbs and fat fairly evenly and advised that the next day would be a low-carb day. It then offered meal plan suggestions and recipes accordingly. Subsequent measurements revealed different patterns based on time of day, meals consumed, activity, etc. After two weeks of measurements, I was shown my flex score which measures how flexible my metabolism is at burning fat and carbs. While waiting on my flex score to unlock, I educated myself on nutrition and metabolic health using the abundant amount of informative content within the app. I am learning all about metabolism, the role of mitochondria, and how things like stress, cortisol levels, diabetes, and other health factors can affect metabolism. I’m even learning why some people constantly crave sweets. The Lumen helps me regulate my metabolism by offering tailored meal plans and macronutrient tips to help correct imbalances. One really useful feature in this pursuit is that the app can utilize AI to identify and record meals using my smartphone’s camera. The app also logs my movement and fitness via my smartphone’s health app. I initially frequently fell on the mostly burning carbs side (4, 5) of the scale due to my moderately high-carb and poorly regulated diet. Since I began following the Lumen app guidance, my results now skew more frequently towards fat burning, and others typically fall in the even range (3), where my body burns both carbs and fats at a near-even pace. Use of the Lumen requires a moderate amount of discipline. I must remember to use it daily when I wake, throughout the day, and at bedtime. Waking and bedtime are the two most important measurements. All others are optional, although they can offer additional helpful insights. The breathing and audible prompts can be loud enough to disturb others nearby, especially if measuring really early in the morning or late at night. I disabled the audio prompts and either go into the bathroom first or find other ways not to disturb my sleeping spouse when measuring. To make it all worthwhile, I try to strictly follow the macronutrient guidelines to effectively coax my body into processing my food more efficiently and burning fat. I perused the meals and found some I liked, some I didn’t. I will likely make some substitutions using the suggested macronutrient amounts from Lumen as a guide. I also must be disciplined in the timing of my meals and stop the poor eating habits that have led to weight gain and suboptimal health. The wealth of helpful knowledge and tips that the Lumen app and plan offer can be used with the metabolic measurements and flex score on a continuous basis. The tips are presented as short silent videos, so they require reading to follow. I don’t know if there is an option for visually impaired users, but I couldn’t find any sound options. The tips required I view previous tips before additional tips would unlock. I wasn’t initially fond of the read-to-unlock-and-continue format, especially since most of the videos I was most interested in are buried beneath several less interesting videos, but I get it. Too many people are stubborn and will want to skip the learning portion and take shortcuts. This device is not for anyone seeking shortcuts because, again, it requires moderate discipline. Lumen also provides an in-app link to their Facebook social media page and an in-app members forum. I rely on the forum, which I prefer over using social media. Another requirement for full app functionality is a paid Lumen membership. Membership options include monthly or annual. The biggest benefits I see with membership are the macronutrient suggestions and tracking, meal suggestions and recipes, and seeing how my body responds to certain meals, exercise, and stress. Much of this can be accomplished manually by people good with meal planning and nutrition knowledge. That’s not really me, so I’m giving the annual membership a go, and if I continue seeing benefits, will renew. The Lumen has been truly helpful for me, particularly in my situation. I’m in recovery from major surgery and spent nearly a year with severely limited mobility. It did a major number on my metabolism, muscle mass, and cardio fitness, all of which plummeted. I was trying to go at it on my own, but it wasn’t going well. I was continuing to lose muscle while accumulating more fat. The Lumen has helped me make better eating decisions and helped tailor my recovery training for maximum benefits. For example, I started running on high-carb days and noticed measurements taken after exercise were in the fat-burning zone rather than even or carbs. That was a major factor in me deciding to give an annual membership a go. And so far, Lumen hasn’t disappointed yet.

When I first heard about Lumen's metabolism tracker, I was a bit skeptical at how a simple, small breathalyzer looking device could be able to track how my body was burning carbs or fat. But since I take medication which can affect my metabolism, I wanted to give it a shot, and I was pleasantly surprised. The box contains the device, a charging pod, a Type-C cable and a some documentation. You will need an Android or Apple smartphone to install the app which records, analyzes and gives you hints, advice and more tools to see what your body is doing. The device itself is fairly easy to use, at least if you have enough breath to get through the sensor recording process, as it uses the gases in your breath to measure what your body is currently burning. The app will then go through the results and offer guidance in form a nutrition plan made to help you burn fat or carbs more efficiently. The tracking requires a morning test and one in the evening. I forgot a couple of times, but the data was enough to demonstrate that the device worked. And I won't lie, I didn't think this was going to work at all. Now, one thing that rubbed me the wrong way was the high cost of the subscriptions. You can of course use the device freely without it, but you can only unlock all the options in the app through a monthly payment to you get the full experience. I found the price to be a bit high and hard to justify, unless you are going to be using it to actually regulate or optimize your metabolism to burn fat or carbs on the long run. In order to analyze what is going on with your metabolism, you will have to learn to inhale for 4 seconds, hold it for 10 and exhale for another 3 seconds or so. The more you do it, the better you will get at it (I have pollen allergies and it's hard to hold my breath for that long without coughing, but the more I did it, the better it got). The device will help you with visual cues which is really neat. Lumen has put out a device which is easy to use, tracks your metabolism very well and offers valuable information on the fly. The nutrition advice is excellent and should get you to shed some weight by only changing some habits. Even though it's not "perfect", it does work and if it wasn't for the high subscription price (I think I speak for most of us when I say that we all have enough subscriptions to deal with). I do recommend Lumen's metabolism tracker, even if it won't get a perfect score from me. Now I'll be waiting for the next amazing device will put out!

I am really torn by this device. On the one hand, it is designed well, is easy to use, and provides some interesting data that typically has not been accessible at home. On the other, it is somewhat limited, really, in what it can do. It may provide a roadmap, but the work is up to you. In both the micro and macro senses. Further, given the cost of the device itself, as well as the required subscription, it is a commitment in that sense as well. The device itself is built well and should stand up over time without issue. In use, it is rather simple. You blow into the device, and it essentially analyzes the CO2 concentration in your breath. This can tell you if you are burning carbs or fats for energy. With this data, the app offers guidance and provides a dietary plan to help you meet your predetermined goals, based on your daily Lumen scores, activity, body, starting point, etc… Frankly, while the device is needed for measurements, the app where everything comes together, and it is done very, very well. It also does sync with many other popular heath services which is very nice to see and sometimes an issue. I can see how the data, guidance, and plan are valuable, but you really have to try be consistent, and in my opinion, to get the most out of this device you should be diligently tracking your food intake. Lumen does help make the process easier with voice log and photo options, so credit there. Certainly, if you are concerned about your health and interested in what this product can do, you would be committed to being consistent and tracking things, a solid strategy regardless, but I just think it was something to note. In the end, I do think this can be a helpful tool for those on their health journey. Not only with data, but also with additional structure and feedback. The device itself does as advertised, as does the app. For the right people, who are committed to both the subscription and the work, I think the value is definitely there.

I tend to track my activity and food intake on a daily basis and, as a part of monitoring my overall health, I thought this metabolism tracker would be interesting to try. To begin, this unit measures your exhaled air to determine whether you are burning carbs or fat. This information is then incorporated via the unit's smartphone app to help develop a nutrition plan for you for the day that targets a specific amount of carbs, protein, and fat. In all, the concept is very interesting and the Lumen support team apparently has the ability to provide suggestions to help tailor a nutrition plan beyond what the app suggests based on dietary constraints (if you already have a special diet through a healthcare provider). They even have a Nutritionist Chat add-on feature to get manual adjustments made to your nutrition plan to align it with specific needs (and receive personalized support from dietitians and Lumen experts). There are also several tools available within their app, such as videos, guides, and links to articles on their website that are designed to help you interpret the data and make positive changes to your nutrition and lifestyle habits with the goal of improving your metabolic flexibility and long-term health. With all that being said, this may be a great device for some folks, depending on where you are in your health journey and what you are attempting to accomplish. Personally, the device is not as innocuous as a wearable device and I found myself forgetting to use it. I suspect someone more disciplined would find the device to be more helpful. I also use a competitor app for tracking my food and could not bring myself to make the change (and lose my historic data). Another thing that I was not fond of, although it seems to be the way things are going nowadays, is that the use of the app requires a subscription after the initial trial period. If you find the information helpful, though, it is probably worth the cost.

I wasn't sure what to expect from this Lumen Metabolism Tracker, but during my short-term use, I came to understand how this little device could be an asset to help people monitor and gradually improve aspects of their health. While setup was relatively simple, I did experience some initial frustration ("user error") which took me a bit of time working through with repetition of steps. There is a companion app you'll need to install on your mobile phone. The Lumen Metabolism Tracker app is required to use the Lumen, but is organized reasonably well, having many useful features and even a social community aspect. You can also connect the Lumen to sync with a compatible wearable or health/activity app. With the app you can track your daily/weekly step count, nightly sleep sessions, even add your workouts. Keep a food log, plan your meals, and track your daily carbs, protein, fat intake. Get daily updates with helpful tips. And learn more about your Lumen, and other health related info, with 'Lumen 101' videos. One of the coolest things I found that the Lumen can do is, while out to breakfast with my husband, I was able to have the app scan my plate and give me a breakdown of ingredients and their calorie count. So awesome! Especially after double-checking with the restaurant's online ingredients and nutrition information. The results the Lumen gave were nearly identical. I will say, that some of the info I gleaned from the Lumen was what I already knew about the current state of my health. Every morning I measure to get my Lumen level based, in part, on what personalized data I've inputed into the app settings. From this I can get a daily plan for nutrition and lifestyle recommendations as the device gets to know me and my needs better, which is then reflected by my Lumen Flex Score. I'm particularly interested in how Lumen might help me with weight loss, and to gain a better understanding of my own personal metabolism. Being post-menopausal, I wish I'd have had this helpful Lumen device years ago. Tip: Remember to clean the mouth-piece at least once a week, though I myself plan to do so every day with the inexpensive alcohol wipes I keep on hand. Overall impression - I most likely will not be paying for the monthly membership in order to continue to make use of all the features Lumen offers, beyond the 1-month trial period. Now, do I think the cost of the device itself is worth it? Yes. Consider it an investment in your long-term health. For those who would make use of the Lumen every day, as part of their personal self-care routine, then most assuredly, yes.

Lumen Metabolic Tracker: A Comprehensive Review I couldn't wait to get my hands on the Lumen metabolic tracker. Having been dedicated to my fitness journey for quite some time, and having successfully lost over 193 lbs at one point, I'm always looking for ways to refine my efforts and build upon my achievements. The Lumen appeared to be the perfect opportunity to further improve my metabolic health. This innovative gadget, paired with a comprehensive app, aims to empower users with real-time insights into their body's fuel source – whether it's burning fats or carbs – and then guides them towards better metabolic flexibility. My Personal Experience After receiving the Lumen, I wanted to test it out for a few days to see how it would work. Downloading the app and following all the prompts to activate my Lumen was straightforward, and I was eager to get started! The very first thing I did was get my initial reading. It came back as a "four," and I immediately delved into what that meant for my body and the steps I needed to take to improve. The app proved incredibly informative, teaching me things I hadn't come across even with all my extensive research into optimal workout strategies. Typically, I prefer to eat something before my workouts to ensure I have enough energy and avoid feeling sluggish at the gym. However, my pre-workout breath analysis with Lumen suggested that I didn't need any immediate carbs, indicating I had sufficient fuel to burn already. Shockingly, I decided to listen, trusting the device and foregoing my usual pre-workout meal. I fully expected to get tired halfway through my session, as is usually the case when I don't fuel up. To my absolute surprise, I completed a full workout and was able to push myself just as hard as I normally do, even without eating anything that day! Over the next few days, I worked diligently to try and achieve better readings, and I was genuinely excited when I finally hit a "two." My ultimate goal is to consistently achieve readings of "one," believing that this will lead to even better results in my fitness journey! How It Works At its core, Lumen utilizes a CO2 sensor and flow meter to measure the carbon dioxide concentration in your breath. This measurement helps determine your "Respiratory Exchange Ratio" (RER), indicating whether your body is primarily using fats or carbohydrates for energy. While traditionally RER measurements were confined to clinical settings, Lumen brings this technology to your home in a portable, user-friendly device. Users typically breathe into the device several times a day, particularly in the morning after an overnight fast, and before/after workouts. The accompanying app then translates these breath readings into a "Lumen score" (on a scale of 1-5), which indicates your current metabolic state. Based on this, the app provides personalized daily nutrition plans, including macronutrient recommendations, and offers lifestyle advice related to sleep, stress, and exercise. Key Features and Benefits Real-Time Metabolic Insights: This is Lumen's standout feature. Getting immediate feedback on your body's fuel source can be incredibly motivating and helps in making informed dietary choices throughout the day. Personalized Nutrition Plans: The app generates daily meal suggestions and macro guidance tailored to your metabolic state and goals. It aims to teach your body to become more "metabolically flexible," meaning it can efficiently switch between burning fats and carbs. Convenience and Portability: The device is small, compact, and easy to carry, allowing for measurements anywhere, anytime. Tracking and Progress: The app provides progress tracking, showing trends in your metabolic flexibility over time and helping you see the impact of your lifestyle choices. Integration with Health Apps: Lumen integrates with popular health and fitness apps like Apple Health, Google Fit, and Garmin, allowing for a more holistic view of your health data. Educational Content: The app offers a library of expert-backed guides and videos to help users deepen their understanding of metabolism and nutrition. Weight Management and Energy: Many users report benefits such as natural weight loss, reduced snacking, increased energy levels, and improved athletic performance due to a better understanding of how to fuel their bodies. Scientifically Validated: Lumen's technology has been featured in peer-reviewed articles and validated against the "gold standard" of metabolic measurement in studies (though some studies involved researchers affiliated with the company). Potential Drawbacks Subscription Model: While the device itself is a one-time purchase, an ongoing subscription is required to access the full features of the app and personalized guidance. This can significantly increase the long-term cost. Warm-up Time: A minor but noticeable inconvenience is the device's warm-up period before you can take a measurement. This can be a bit irritating, especially when you're trying to get a quick reading. Consistency Required: To get accurate and meaningful data, consistent daily usage and meticulous logging of meals are necessary, which can be time-consuming for some. Emphasis on Low-Carb: The meal suggestions often lean towards lower-carb options, which may not be ideal for everyone, including endurance athletes or individuals with specific dietary needs. Not a Standalone Solution: Lumen is a tool for insights and guidance, not a magic bullet. It still requires active participation, discipline, and a commitment to lifestyle changes to see significant results. Data Interpretation: While the device simplifies complex metabolic science, some users might question the direct applicability of a "flex score" or find the recommendations occasionally simplistic or repetitive. Smartphone Dependency: The device requires a smartphone and data connection to function, as all data and recommendations are provided through the app. Is Lumen Right for You? The Lumen metabolic tracker can be a valuable tool for individuals who are highly motivated to understand their metabolism, are comfortable with consistent tracking, and are willing to adapt their diet and lifestyle based on the provided insights. It offers an impressive, non-invasive way to gain a deeper understanding of how your body uses fuel. However, if you're looking for a quick fix, are unwilling to commit to daily tracking, or prefer a less data-driven approach to health, the investment in Lumen (both financially and in terms of time commitment) might not be worthwhile. For many, focusing on fundamental healthy habits like balanced nutrition, regular exercise, adequate sleep, and stress management may yield similar benefits without the need for a specialized device and subscription. Ultimately, Lumen empowers you with personalized metabolic data, but the true transformation comes from how you choose to act upon that knowledge. Final Recommendation Based on my experience, I definitely recommend the Lumen metabolic tracker to anyone who is serious about trying to hit their fitness goals and can use all the help they need. It provides truly insightful data that can help optimize your efforts and push past plateaus.

The information this device provides is interesting. While the majority of the information it provides is most likely what I know already based on the kinds of foods I eat and when I eat them, there’s certainly some deeper insights to be had in regards to when my body actually goes into more fat burning states vs being in carb-burning states. This is especially interesting for me as someone who intermittent fasts on a daily basis so seeing how my body responds to food during the evening as well as how it’s responding in the morning, and as I get into the later stages of my fast is fascinating to see. It’s just neat to see the timing behind it all and when my body goes into different states. Again, it’s information I probably already know but it's cool data to back it up. There’s an additional, and optional, subscription that can be purchased that provides historical data as well as tailored guidance in regards to nutrition and other topics. I’ve been using it with the initial 1-month trial that comes with the device but I’m not sure I’ll renew when the trial is over considering the device apparently still works for taking on-demand measurements, which is probably all I need. I tend to geek out on nutrition and biohacking already so I have a bit of knowledge around that realm, however I could certainly see the premium features being useful for someone who could benefit from the guidance it provides. It could be one of those things where the premium features could be used to adjust daily habits initially but once a routine has been established that aligns with metabolism goals, the subscription may not be needed at that point. The breathing process can be tricky on some occasions though. It initially took me a few tries to get my first reading and found the trick is to be very consistent and stable with each inhale and exhale and not breathe with too much force. They have a guide where you have to keep a ball within a circle during the process which indicates the amount of force you need to have but I found it tricky to stay consistent with each step.

So I was very intrigued with the device. As someone taking a GLP-1 medication, to help with my weightless and a technologist, was interested to see what this device could do to help we with the journey. It is going to take some time, and I am just about 2 weeks into using it, and it says it will take about a month to really get to know me, and my patterns... but so far, it has been interesting. It is a sleek device, very lightweight, easy to charge in the included charging base... but once again as becoming very common lately, no adapter. They give you the USB wire, but no plug. It is a charging base, not a direct plug to the device, so don't lose the charging base. BUT!!! The device is going to last a LONG LONG time between charges, so you a charge, and put the base away. Setting up the device at first was frustrating. The iOS Application will need some tweaking, as I was able to get myself into an endless loop during the setup, and had to terminate the app. A tip: You are going to have to inhale and exhale a LOT harder then you think you will have to. I recommend on your first attempt, just inhale and exhale SIGNIFICANTLY, so you can see the dot move. I tried many many times and thought the device was broken, because it just wasn't moving the dot. But now the I know, it is really easy to use. Takes about 1 minute for the device to turn on, warm up, and capture the data... and then you are done. One down side, you do need to measure several points in the day, so you can/shoudl carry it with you or have it in an area you frequent a lot. The data that is shown in the app, is interesting, and the app attempts to explain. But again, goin to take some time to see it really change or trend... so I can seee what to do to help with my weight loss. So I am very intrigued on where I will be in 2 months or so, and what the data tells me and my Dr.

I’ve been into fitness for a few years now and I am now age 43. It’s time in my life to start thinking about eating healthier and cutting out the bad habits like candy, soda, fatty foods, etc.. Lumen can help me do that. First off, everything was packaged really nicely inside its box. Included in the box is the lumen itself, with its handy magnetic cap to store away when you are not using it. There’s a carrying pouch a USB-C, charging cable instructions and last, but not least it’s charging base. The first thing I did was start charging my lumen right away. It was fully charged from what I could see out of the box, but I still decided to charge it for an hour or so before I started using it just to make sure. The second thing I did was look at the instruction manual, it’s not overly complicated, but it does give you some important information. The next thing I did was download the app. I’m sure this will get corrected, but on the instructions it says to download the Lumen Metabolism Tracker but the app itself is called Lumen Metabolic Coach. No big deal. I just thought I’d mention that in case somebody is reading my review and wondering the same thing. When you buy a lumen, there is a subscription you eventually have to pay for. I believe you get one month free to start off. This is important information that somebody reading my review should know if they don’t already. In the app, there are “tools” these tools help you with such things as ordering food, logging in everything you eat and drink, and the most important tool in my opinion is the “Scan” basically what it is is you take a picture of what you’re about to eat. it then very accurately tells you what it is. What’s on it and how many carbs, protein, and fat it has. I was amazed at how accurate it was, at first I started taking pictures of fruit. It knew exactly what it was, OK not very impressive right? I took a picture of a ham sandwich and it knew it was a ham sandwich. I took a picture of a tostada that I had a fried egg on top with avocado and queso fresco, it identified that as well. I’m sure it won’t be 100% accurate all the time but I was very surprised at how accurate it was for me. So far everything has been great, between the Lumen device itself analyzing my breath and detecting if i’ve should cut back on carbs, and logging my food in lntake each day, I know exactly how many carbs, protein, calories and fat ive had each day. Seeing these results on paper (or in this case through the app) you’ll get a better understanding and be more conscious about what you eat, and make the appropriate changes if necessary. We all know we should eat better but now you can track it and see it and you’ll be using technology to help you meet yours goals.

I’ve been using the Lumen Metabolism Tracker for a week now and I definitely have some mixed feelings. It’s a really interesting product, and once you start figuring it out, it can give you some surprisingly useful insights into your body. But at the same time, it definitely takes some getting used to, and it’s not as seamless or intuitive as I hoped it would be at first. When I first got it, I was pretty excited. The packaging was clean and the device itself looks super sleek. It doesn’t feel like a bulky health gadget or anything. It’s small, easy to hold, and doesn’t take up a ton of space, which is nice if you’re someone who travels or just doesn’t like a bunch of clutter. Setting it up wasn’t hard either. The app walks you through everything step by step, and pairing it to my phone was fast. That part felt pretty modern and simple. Where it started to get frustrating was with the actual breath tests. I didn’t expect them to be so picky. To get a proper reading, you have to inhale through the device, hold your breath for 10 seconds, and then exhale steadily. I thought I was doing it right, but for the first few days, I kept getting errors or being told to try again. Sometimes it would kick me out or restart, and it was just kind of a pain. Especially first thing in the morning when you’re half asleep and just trying to get the thing to work so you can start your day. Eventually I got the hang of how it wanted me to breathe, and once that clicked, the process went smoother. But it did take a few tries, and it was honestly annoying in the beginning. If you’re not patient or you’re someone who gives up on new gadgets easily, just be warned. It’s not instantly user-friendly. It kind of makes you earn the results. That said, once I started getting regular readings, that’s when things started getting really cool. The Lumen tells you whether your body is burning carbs, fat, or a mix of both based on your breath. I’ve always had a general idea of how food affects me, but seeing it in real time based on actual data from my body was super eye-opening. There were days where I thought I was doing everything right, eating light or healthy, and it would show that I was still in carb-burning mode. Other days when I felt like I’d slipped a little or didn’t eat perfectly, it would show I was burning fat. It really made me realize that my assumptions don’t always match what’s actually happening in my metabolism. The app also gives you daily nutrition suggestions based on your readings. It’s not overly complicated or stressful. It’ll just tell you if you should aim for a low-carb, balanced, or high-carb day. I’m not a person who wants to track every gram of food I eat, so I appreciated that the advice was simple and more like a general guide than a strict plan. You can also log meals, workouts, and sleep, and it tries to show you how all those things tie together. After a few days, you can actually start to see some patterns, like how poor sleep or a late meal might keep you in carb-burning mode longer than expected. I will say, trying to remember to do breath tests throughout the day gets tedious fast. You’re supposed to do one first thing in the morning before you eat or drink anything, then again before meals, after workouts, and sometimes before bed. That’s a lot. Some days I was on it and remembered to do them, but other times I left the device at home or just forgot completely. And if you miss the morning reading, it kind of throws the rest of the day off because that’s the baseline the app uses to figure out your daily nutrition plan. I found myself wishing the app had better reminders or more flexibility. Like maybe syncing with a smartwatch or giving more grace if you miss a measurement. Still, despite all that, I’m glad I got it. In just one week, I’ve already learned a lot about how my body uses energy. I feel like I have a better sense of how certain foods or habits affect me. It hasn’t magically fixed anything, but it’s made me more mindful, which I think is the first step toward better habits. I’m using it mainly for weight loss and energy management, but even beyond that, it just feels empowering to understand what’s going on inside my body without having to guess. The device itself feels durable and well made, and the battery lasts a while between charges, which is a nice bonus. The app is sleek and easy to navigate once you get familiar with it. My only real complaint is just how particular it is about the breathing technique and how easy it is to get thrown off if you don’t use it exactly as instructed. I also wish it wasn’t so tied to strict timing. I don’t always want to carry it around or interrupt my day to breathe into something. But at the end of the day, that’s part of the commitment if you want consistent data. Overall, I think Lumen is a great tool if you’re ready to invest a little bit of time into understanding your metabolism. It’s not the kind of thing you buy and forget about. It takes active use and a little patience, especially at the start. But it does deliver real insights, and for anyone serious about improving their health, it can be a really powerful resource. Just be ready to stick with it, and know that it won’t be perfect right out of the gate. For me, even in just a week, it’s already changed the way I think about my food, my energy, and my daily habits

I’ve been working with a keto diet and intermittent fasting for some time and have always wanted a tool that would give me a view of what it happening while I’m doing that. I have in the past used glucose and ketosis meters, which involve a pin prick on the finger, but when I found out that Lumen provides a breath-based, dynamic experience to determine what my metabolism is doing, I wanted it. Right off the bat, the tracker was easy to set up. You need an app on your phone, and it connects by Bluetooth, but it was a standard pairing experience, just like your earbuds or car. The app detects the tracker immediately, and there are fun graphics that to me speak to it’s being a life device (breathing type animations, smooth transitions) and it guides you through the process of taking a measurement. You inhale through the device when prompted, keep a dot in a circle for a few seconds, and it then tells you to hold for a short time, and then exhale back through it, again keeping the dot in the circle. The readout is a 5-pane meter, that for all intents gives you how much fat versus how much carb burn you are achieving in the moment. This is great for someone who is doing keto because the hope is you are a “1 or 2” and not in the “4 to 5” range. After you begin the reading process, the app then takes you through a coaching experience that is gentle and useful, with diet suggestions, a motivational component to exercise, and then you can put it away if you are content. It’s a really fun device to be honest if you are doing a keto lifestyle. I can see this as being a useful tool for someone dealing with diabetic symptoms or conditions. Of course, it’s not a substitute for medical care, but it is a great way to keep tabs on yourself everyday. I really am having fun with this from a health standpoint. I highly recommend this if you are using glucose or keto meters, or to supplement your doctor’s monitoring.

The Lumen Metabolism tracker is a game changer for fasting, dieting, and making healthy decisions in relation to when and what you’re eating. Setup was a breeze, and after only a couple attempts I figured out how to accurately accomplish the breathing process required to take your readings. It only takes a week or so to start getting some useful data and recommendations to maximize your metabolism, you can do readings multiple times during the day timed around workouts and meals, but the morning reading is the only essential reading to get great data and recommendations. I love that the app helps guide you on when to eat certain types of food, and when you should be fasting. It really helps if you are carb conscious or are just trying to lose or maintain weight. Over time it gets more and more educated on how your body processes fat and carbs and really hones in on when you should intake your carbs every day. The battery life is amazing, I’ve only had to charge it once and it lasts an entire week with battery to spare. Add in the nice carrying case and you have a great way to hack your metabolism on the go. I love it!

The Lumen device is easy to charge and set up out of the box but using the device might not be for everyone. I think app is challenging to figure out, but this might be because I'm used to other food tracking apps. I had trouble logging food and exercise in the app. There is a definite learning curve. Using the device was not hard because the app guides you. You must sit down while breathing into the unit. I felt like that was a little silly but it was challenging for me. I am usually on my feet so much of the day and I would rather be able to stand to take the breathing measurements. All of my days I measured it led me to eat a low carb day. I never got a medium or higher carb day reading. I thought this device didn't want you to be low carb but seeing as I always got a "eat low carb day" I'm not sure if this device is supposed to make you eat low carb but that's what it started to feel like. The app guides you to check your breath when you wake, before you eat, an hour after you eat, before you exercise, after you exercise, after any fasting, before bed, or any other custom time you choose. If you want to stick with this device you have to think about using the Lumen device constantly through your day, which I found very challenging.

I've been using the Lumen Metabolism tracker for a week now. First a little about me. Mid 40's male, with a BMI around 24. I've been getting myself back on track with personal fitness including walking 4-6 miles a day and jiu-jitsu. Since losing weight or gaining muscle is largely a matter of diet, I decided to try the Lumen to see what's going on with my body's response to food. Lumen works by measuring the CO2 output in your breath to determine if you're burning fat or carbohydrates for fuel at any given time. The app, like many others, wants to pull all your health data together into a comprehensive dashboard, which is handy. I tried to be consistent about using Lumen when I woke up and before I went to bed. It was great about telling me what my body is using for fuel at any given time. I haven't quite gotten the hang of making actions to direct my metabolism yet. Some days I have a score of a 1 (high fat burn) and others I wake up at a 3. While this is insightful, I don't find it to be really ACTIONABLE yet. The Lumen app does offer meal suggestions for a given day based on where you are in your metabolic cycle, but this doesn't quite feel useful. We meal plan for the week and not one day at a time. Overall, pick this up if you want to be able to dial in what your body is doing, but don't expect it to be the solution for you. You will still need to take actions to make the most of it.

Even if this works, at this procing and membership point, there is no way it becomes popular. Odds are the company will not last more than a couple years and you will have a $200 paperweight.