Total Shape is a reader-supported site. Purchases made through links may earn a commission. Learn more.

Lumen Review
Is This Metabolism Tracker Any Good?

Last updated: April 9, 2021

Are you over 50, hoping to learn about the Lumen dating site?

I’m afraid you’ll leave this place disappointed.

But, if you’re curious about the latest Lumen health accessory, I bet we can satisfy your curiosity, so bear with us.

I’ve created this in-depth review to share the details on how exactly the device can hack your metabolism, what’s the science behind it, what secrets below the hood it can reveal to you, who it’s best for, and other information necessary to figure out whether it’s right for you.

Let’s find out.

What Is Lumen and Who Is It For?

Lumen metabolism trackerLumen is an electronic metabolism tracker developed by a health and wellness company Metaflow LTD to measure your carbs and fat levels simply by using your breath, and find out whether you’re burning carbs or fat to fuel your body.

The metabolic score it provides can help you adjust your lifestyle, customize your diet, optimize your exercise regimen based on your body’s actual needs, and make decisions that will lead to your desired goals faster.

More details on how the device works a bit later.


It’s designed by Israeli twin sisters Michal and Merav Mor, Ironman triathletes, and may be useful not only for professional athletes and trainers but for anyone who exercises regularly and wants to gain insights into how their body works.

For instance, someone who’s already on a paleo, keto, low-carb, high-protein, or any other diet but hitting a muscle-building or fat-loss plateau may greatly benefit from Lumen’s customizable workout and nutrition plan based on each user's individual sleeping and eating habits and specific goals.

You get those guidelines in addition to daily ketone measurements from your breath so that you always know whether you’re in ketosis, i.e. burning fat for energy.

I should also say that this gadget isn’t recommended for anyone under 16, obese people, or those with chronic health conditions like asthma, diabetes, COPD, and similar.

25$ OFF using code Totalshape

Pros and Cons

Here are a quick run down of the pros and cons of the tracker.

  • Sleek design
  • High-quality hardware
  • Portable, handheld, easy-to-charge, and simple-to-use device
  • Provides immediate real-time carbs and fat measurement, helping you customize your training goals and nutrition plan as needed without guesswork
  • Compatible with iOS and Android devices
  • The app offers plenty of resources to encourage sensible health decisions based on your testing score
  • Allows extended fasting
  • The price may be higher (but it’s cheaper and more convenient than traditional RER metabolic testing or regular glucose and ketone blood tests)

How Does this Device Work?

woman using the lumen metabolism tracker

Here’s how the Lumen device works in short and what’s the science behind it.

This metabolic tracker measures the concentration of CO2 in your breath to determine your current body’s fuel - carbs or fat.

Low CO2 levels indicate you’re burning fat, whereas high CO2 levels mean you’re burning carbs for fuel.

Based on the readings, you get personalized recommendations on workouts, sleep, or nutrition,  like what and when you should eat that day, etc.

This at-home tool is said to provide comparable results to the standard clinic Respiratory Exchange Ratio (RER) method that requires much more time and money to test an individual’s metabolic state. [1]

However, the studies claiming this technology’s scientifically proven to be accurate are internal and haven’t been peer-reviewed.

Still, some other researchers have said their studies show that similar portable devices are mostly precise and can deliver accurate results, so they deserve closer attention and further research. [2] [3] [4]

How Can Lumen Help Improve Your Health?

a bunch of girls using lumen metabolism tracker

Whether you’re already following a specific workout and diet plan or just paving your way to healthy nutrition, Lumen enables you to listen to your body, understand it and make better, personalized workout and eating decisions based on its analysis.

“Metabolic flexibility is the main player that extends behind everything -- behind performance, weight loss, longevity, energy. So, we first want our user to achieve healthy metabolism, flexible metabolism, and the outcome of that is a weight-loss improvement.”


-Michal Mor, Lumen Co-Founder

It’s aimed at improving your flex score, i.e. metabolic flexibility - your body’s ability to switch between different fuel types easily, which results in: 

  • Increased energy levels
  • Enhanced physical and mental performance
  • Faster fat burning and lean muscle mass building
  • Better sleep quality
  • Lower risks of metabolic, cardiovascular, and other diseases

How to Use It Properly

I’ve tried to simplify this process and filter the most relevant information in the instructions below so that you understand the gist.

Step 1: Set-Up

The first step is to download the mobile app on your smartphone, sign up for an account, and connect your device to the app via Bluetooth. (You can log all your data through the app, review the stats, and make adjustments later if you want.)

Then you answer a few questions about your lifestyle, physiology, health goals, etc. such as your activity level, sleep pattern, and similar.

Step 2: Regular Usage

That's it, you can welcome this pal to your regular daily routine.

Each time you use it, you need to inhale a particular volume of air through it, hold your breath for ten seconds, and fully exhale until a soothing circle on the screen disappears.

Then, you receive a 1-5 score, showing whether you’re burning fat or carbs for energy. We could roughly put the test scores into three groups: 

  • 1 or 2 for a fat-burning state
  • 4 or 5 for running on carbs and
  • 3 for a combination of the two energy sources.

Lumen typically suggests your daily nutrition plan based on your morning score in the previous few days, advising you whether to eat low-carb, medium-carb, or high-carb food that day, including the amount of protein, fat, and carbs.

“We are not trying to recommend a specific food, [like] today eat chicken with rice and some vegetables. That’s not sustainable.”


Michal Mor, Lumen Co-Founder

General Tips

a man holding a measuring device in his hands

If you want to see the effects of a particular food on your body, you can take measurements one to two hours after eating it.

Similarly, to find out how exercise influences your body, you can take measurements half an hour after your training.

For the best results, make sure you’re relaxed while taking measurements, preferably in a sitting position with normalized heart rate, i.e. at least half an hour after any activities.

Where Can You Buy It?

lumen metabolism trackerI always recommend buying any health-related devices and supplements directly from the manufacturer’s official website to make sure you’ll get a genuine product, discounts, warranty, refund or satisfaction guarantee, and other similar benefits.

The same goes for Lumen.

When you purchase this handy gadget and open the box, you’ll also find a charging dock, USB-C charging cable, and a travel case in the package.

Plus, you get access to the Lumen App, which is compatible with iOS and Android smartphones, and premium customer support.

All this comes with a 30-day money-back guarantee, one-year warranty, and free US shipping, plus 10% off for ordering two devices.

25$ OFF using code Totalshape

Lumen User Reviews

user reviews

After analyzing testimonials that people using Lumen share online, I’ve noticed high ratings and 85% of positive reviews with plenty of compliments and very few complaints.

Customers have mainly complained about the lack of integration with other fitness services.

Below are the experiences of some satisfied Lumen users, both individuals and fitness trainers who work with clients.

You may take a look at how this pocket-sized gadget has helped them meet their various goals from breaking through the plateau and getting leaner, learning how to eat healthier, gaining strength, improving endurance, and more.

“I’ve been using it for over 2 weeks now and I love that it’s easy to use and provides such great feedback on the habits that negatively affects my metabolism. It motivates me to work harder and better!”


- Kim R.

“Seeing the actual numbers helps me perform and recover at my best. I’m 7 weeks in and my recovery times and energy during workouts have improved a ton. I highly recommend Lumen if you want to be more in touch with your metabolism works.”


- Edgar E.

And here’s how Dr. Molly Maloof reviews the Lumen metabolism tracking technology:



Does Lumen Help You Lose Weight?

Yes, Lumen does help you lose weight in a way that it guides you to better fat utilization, helping improve your metabolic flexibility, and keeping you motivated to stick to your healthy diet plan.

Can Two People Use the Same Lumen?

No, two people can’t use the same Lumen. I mean, theoretically, they can, but it’s neither convenient nor recommended.

The device is designed for individual use. To get the most out of it, users should download the Lumen Apps to their smartphones, create a personal profile, and do breath measurement consistently throughout each day to get meal plans and other helpful health and exercise tips on the way towards achieving their personal fitness goals.

How Much Does Lumen Metabolism Tracker Cost?

Lumen metabolism tracker costs $349, but there’s a limited time offer at the moment so you can get it for $299.

Before you order your device, it’s always better to check the current pricing, discounts, and any available special offers on the official Lumen website

Is Lumen Accurate?

Yes, Lumen is accurate provided that you closely follow the instructions of the Lumen app, as well as the breathing protocol when using the tool.

Is Lumen Safe to Use?

Yes, Lumen is completely safe to use. It’s just a breath analyzer that helps track your metabolism to achieve your desired goals faster.

Should You Buy Lumen?

You’ll hopefully be able to answer this question for yourself after reading this review.

I’d certainly recommend Lumen as a handy companion to anyone who’s serious about achieving their fitness, diet, and health goals because its valuable readings and guidelines can make you aware of what workout or eating habits may undermine your weight and other goals, suggesting effective ways to overcome those obstacles.

Check it out to see if it lives up to your expectations. Then, let us know what you think.

Lumen tracker


Our #1 Recommendation

  • High-quality hardware
  • Portable, handheld, easy-to-charge, and simple-to-use device
  • Provides immediate real-time carbs and fat measurement, helping you customize your training goals and nutrition plan as needed without guesswork
  • Compatible with iOS and Android devices
  • Get 25$ OFF using code Totalshape
Click For Best Price
payment icons


Join the discussion here on Facebook.

About the author

You may also like

Write a Reply or Comment

Your email address will not be published. Required fields are marked *