Lumen Review 2023: Does This Metabolism Tracker Really Work?

Woman holding Lumen

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If I so much as look at a juicy cheeseburger or a lovely cheese pizza without immediately running a marathon, I will pack on a couple of pounds—or at least, this is how it feels. Then on the flipside, there are those who were seemingly born with the scorching metabolism of demi-gods.

Lumen, a handheld device that measures your metabolism by analyzing your breath, claims that it is a way to "hack your metabolism." This Lumen review will show if it's possible to level the metabolism playing field for us mere mortals.


What is Lumen?

To understand Lumen, you first need to understand metabolism. For the metabolism masters who are reading this, feel free to skip the following paragraph. However, for the rest of us, bear with me as I break down the often vexing metabolism.

According to Harvard Medical School, metabolism is your body's internal process of expending energy and burning calories. Your metabolism converts the food you eat into the energy you need to survive. Your metabolism is always running, however the speed of your metabolism varies from person to person, and this is mostly determined by your genetics.

If you're thinking, "Well, not much I can do about my metabolism—thanks, ancestors," don't despair. It is possible to rev up your metabolism, and that's where Lumen comes in.

Lumen is a portable metabolic tracker that was developed as a cost-effective way to measure metabolism by analyzing breath to determine carbon dioxide (CO2) levels.

According to the University of Western Australia, carbon dioxide production alongside oxygen consumption can be used as indirect measures of metabolic rate. When you breathe into the Lumen it measures your levels of CO2. These measurements provide feedback on if you're using carbs or fats to fuel your body. If you're wondering why you should care about this, it's because the factor of metabolic flexibility (your body's ability to switch between fat and carbohydrates based on their availability) is paramount to the speed of your metabolism.

The science for analyzing breath to measure carbon dioxide (CO2) isn't new. However, it was an expensive and time-consuming test that wasn't readily offered to the general public. Lumen changes that by allowing anyone with the interest and the budget (although much less expensive than traditional testing, Lumen isn't exactly cheap) to determine and track their metabolism.

How Does Lumen Work? 

Admittedly, Lumen immediately reminded me of a breathalyzer. And for good reason; the two measurement devices are used in similar ways. However, where a breathalyzer measures blood-alcohol levels, Lumen uses your breath to determine if fats or carbs are fueling your body.

This small, portable metabolic tracking device has a sleek, modern triangular design made primarily from plastic. The area where you place your mouth is made from metal and comes with a protective magnetic cap that should be kept over it when not in use. To analyze your carbon dioxide levels, you need to steadily and continuously blow into the device for 10 seconds.

Lumen works on a subscription basis that you pay for through the Lumen app. When you pay for your subscription, you will receive the metabolism tracking device for free. You can choose from three tracks:

  • 6-month track: $249
  • 12-month track: $299
  • 18-month track: $349


Lumen Score

Once this is complete, Lumen will give you a score between 1-5 based on how high your CO2 reading is. An ideal reading is 1-2 as this indicates that you're burning fat. If your analysis brings back a score of 4 or 5, you're using up your carbohydrates, whereas a 3 means that fats and carbs are both providing energy.

Lumen App

After your score has been determined, you will receive recommendations on the amount of fats, carbs, and proteins you should include in your diet via the app. The goal of your tailored meal plans is to make your metabolism more efficient. Additionally, the app is chock full of recipes, tips, and recommendations on how to lose weight and live a healthier lifestyle in general.

Unfortunately, the one area that the Lumen app largely avoids is exercise. This seems odd considering the role that working out plays in the speed of your metabolism.

Lumen Connectivity

Lumen is easily integrated with Apple devices, such as the Apple Watch, iPhone, and Apple Health. Android users can connect to their Lumen via Bluetooth.

The connectivity seems to go pretty smoothly, but there have been some complaints of people having connectivity issues if their phone (or other devices) had a low battery life at the time.



  • Dimensions: 102mm x 41.4mm x 33.3mm
  • Battery: Lithium polymer battery
  • Battery Charge: Up to 2 weeks without charge
  • Connectivity: Apple iPhone 6 and later, Android
  • Sensor: CO2
  • Connection for Charging: USB-C

What We Like

  • Lightweight and easily transportable
  • Sleek and pleasing to the eye
  • Easy connectivity

What We Don't Like

  • Expensive
  • Does not encourage exercise
  • Some aspects, such as "boost days" and recipes, can be bit confusing

BUY: Lumen Metabolism Tracker

Who Should Use Lumen?

People who have already taken steps in their health and wellness journey and would like to now really hone in on the nutrition aspect could benefit from the Lumen. It is also a good tool for competitive athletes because it gives you a daily macros goal.

For Lumen to be effective you must be committed to using it several times a day. Furthermore, this metabolic tracker gives you the tools to "hack your metabolism," but it is not a magic potion—you will have to consistently follow it.

Why Trust Us?'s editorial team relies on the knowledge and experience of fitness and wellness experts including competitive athletes, coaches, physical therapists, nutritionists, and certified trainers. This helps us ensure the products we feature are of the highest standard. Collectively, the team has spent countless hours researching equipment, gear, and recovery tools in order to create the most accurate, authentic content for our readers. Customer satisfaction is also a key part of our review process, which is why we only feature products that are highly rated.


FAQs About Lumen

Is the Lumen device worth it?

The Lumen device can help you understand and potentially speed up your metabolism. If you are committed to using the device several times a day and to following the dietary recommendations, it is definitely worth it.

How reliable is Lumen?

The Lumen's connectivity is reliable. Some users have noted that there is a lag in connectivity when their device battery is low, but overall it provides a consistent connection.

Is there a monthly fee for Lumen?

Lumen is a subscription-based service. The Lumen device is free once you subscribe (there are three tracks: 6, 12, and 18 months). After your initial track time period is up, you are charged on a monthly basis.

Can you use Lumen without a subscription?

No, the only way to use Lumen is with a subscription.

How many users can use Lumen?

Lumen can be used by up to two people. They offer a duo package featuring one device and two memberships. 

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