Lumen is the world’s first device to measure your metabolism in real time.
A pocket-sized nutritionist, the award-winning Lumen app and device provides data in a single breath on your body’s primary source of fuel: carbs or fats.

The Lumen device helps you improve metabolic health by optimizing your nutrition, sleep, workouts, and other factors for better metabolic flexibility (your body’s ability to switch between using fats or carbs as a source of fuel).

Lumen works with Apple Health to sync data on your activity and sleep.

Features include:
* Real-time measurement of your metabolism
* Personalized daily nutrition plan and insights
* Lifestyle recommendations for sleep, exercise, fasting, and more
* Track and monitor your metabolism over time
* Customizable tracks to achieve your goals

Featured in:
Forbes, BBC News, TechCrunch,, Wired Magazine, Shape Magazine and more

Lumen was chosen by the Esquire 2020 product awards “Best product to learn about you”

Winner of the CES 2019 Best Reviews Award

Listed in the Top 30 Best Devices CES 2019

Please note:
You must have the Lumen device to use this app. You can order your device from
While Lumen is not intended as a medical device, it is recommended to consult your doctor before starting any nutrition plan.

Interested in partnering with us? Get in touch with us

Join us and begin your Lumen journey today!

What’s New

Version 2.4.788

Thanks for using Lumen! This update includes new features to keep you on track with your Lumen goals

Ratings and Reviews

4.5 out of 5
879 Ratings

879 Ratings

Buddha Mama ,

Does not sync steps

I don’t carry around my phone. I wear a Fitbit. The steps accounted for can mislead the data used to provide my daily recommendations. I hope this changes. There can be so much more instruction in the actual functions of the app so I use it correctly. There are two places to read a breath without explanation to the functions. I wish the breaths were time stamped. Lastly, the food recommendations do not total the recommended macros. I use My Fitness Pal app and its is much more accurate as many foods co rain a combination of macros. I hope lumen can sync with My Fitness Pal App as well.
I love the device. I’m making exact recommendations because I want it to be superior and used to it’s fullest extent. My FAVORITE is Ulkire, my lumen advisor. She is patient an amazing and always there to support me and answer my questions. If it weren’t for her I would’ve thrown this thing in the garbage because there was no manual in it’s use, just the science behind the concepts.
Keep going Lumen! I’m a professional dieter! We can do this!

Developer Response ,

Hi, thank you for rating and for all the feedback, we will definitely pass it along to our product team and we have passed your kind words over to Ulrike :)

capri64 ,

Super useful product

I’ve been using my Lumen everyday now after I gained the COVID-19-10! I had to do something. I was at my highest weight ever. With Lumen, I was able to lose that 10 plus 10 more. I’m still on track to lose more. It’s a very gentle device and’s never going to yell at you, berate you, etc. It just gently gently guides you in the morning as to what level of carbs you should shoot for...I usually am in the target area of 60 carbs...sometimes 15 carbs less, sometimes 15 more. When I have streaks of successful breath measurements after successive low carb days (like 45 grams) where the device says I’m burning fat like crazy, it will test my metabolism by hiking up the carbs to a high(ish) level, just to keep me metabolically flexible. I’ve tried total keto for over a year, and that just didn’t work for me. Likewise counting calories hasn’t worked for decades. Similarly, with carb loading, that just made lose and regain the same few pounds. This is working. 20 pounds down! I will keep with it.

Developer Response ,

Thank you for this feedback, we're very happy to hear Lumen is supporting you in reaching your goals of weight loss! Amazing progress :)

JD94114 ,

Amazing results using Lumen

I’ve never written a review for any app before but I’m so impressed by the results I’ve experienced using Lumen that I wanted to share. I’ve used Lose It to track my diet and calories for years and have achieved decent weight loss results until a couple of years ago when I seemed to plateau eating 1,800 calories a day. The only difference in my weight seemed to result from how much exercise I did. Using Lumen for just over a week, I lost a pound (I know not much) but I’ve noticed my clothes fitting a little looser and I was eating around 2,200 calories per day at the recommendation of the Lumen app. I’ve been really focused on achieving the recommended macro portions (fat/carb/protein) which I never really paid attention to using Lose It alone. I’ve felt completely full, no cravings, etc and I’m eating stuff I like. Biggest change to my diet since using Lumen is doubling my protein intake. Really looking forward to seeing my results after a few months.

Developer Response ,

We appreciate you taking the time to review JD :) We are glad Lumen has helped you in making a positive change in your diet!

App Privacy

The developer, Metaflow, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Linked to You

The following data may be collected and linked to your identity:

  • Health & Fitness
  • Contact Info
  • User Content
  • Search History
  • Identifiers
  • Usage Data
  • Sensitive Info
  • Diagnostics
  • Other Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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