WORLD'S FIRST HANDHELD METABOLIC COACH
Your breath knows
what to eat today
One breath into Lumen's CO2 sensor tells you whether you're burning fat or carbs, and delivers a personalized nutrition plan for the day ahead. No diets. No guessing.
As seen on
It starts with a breath
Lumen is the world's first hand-held, portable device to accurately measure metabolism. Once available only to top athletes, in hospitals and clinics, metabolic testing is now available to everyone.
The science isn't new, but the technology is
Lumen uses a CO2 sensor and flow meter to determine the CO2 concentration in a single breath. This indicates the type of fuel your body is using to produce energy.
Validated by peer-reviewed scientific research
Trusted by top universities and research centers around the world.
Cutting-edge hardware meets innovation
The Lumen device uses a CO₂ sensor and flow meter to determine the CO₂ concentration in your breath, letting you know if you're burning carbs or fats for energy in real-time.
Trusted by doctors and health experts
Hear why leading doctors and researchers recommend tracking your metabolism every day
What you get with Lumen
Measure your
metabolism daily
One breath each morning tells you how food, sleep, and movement affect whether you're burning fat or carbs, and when to break your fast.
Eat for how your
body woke up today
Lumen builds a personalized daily plan that shows you what to eat, how much, and when. No calorie counting, no guessing.
Burn fat and
preserve muscle
Lumen spots when your body is at risk of breaking down muscle - and tells you what to do next. So weight loss comes from fat, not muscle.
Fuel your workouts
and recover smarter
Breathe before you train to see if your body is ready to burn fat or needs carbs first. Breathe after to see how it responded and what your body needs to recover.
40+ integrations
Sync Lumen with your favorite health apps and wearables for a seamless, data-driven experience.
Real people. Real results.
Sharon lost 30 lbs coupling
Lumen with GLP-1
Nadia lost 3% body fat with Lumen
Amy lost 26 lbs on her
journey with Lumen
Lumen's Scientific Research & Collaborations
Lumen uses a CO2 sensor and flow meter to determine the CO2 concentration in a single breath. This indicates the type of fuel your body is using to produce energy.
Your Day With Lumen
Take control of your metabolism
Many of the factors that impact your metabolism are within your control and can be changed to improve your body's metabolic flexibility, which is your metabolism's ability to efficiently switch between using carbs or fats as a source of energy.
Each morning, you'll breathe into Lumen to see the source of your body's energy: fats or carbs.
Based on this metabolic data, Lumen will provide a daily personalized nutrition plan, as well as other actionable insights on your sleep, workouts, and meal timing.
Lumen tracks your sleep, nutrition and exercise in order to provide you with a score that reflects how healthy your metabolism is.
Lumen trains your metabolism to use the food you eat more efficiently.
When your metabolism is more flexible, you are better able to burn fat instead of carbs, leading to weight loss.
By focusing on metabolism instead of restrictive or unsustainable diets, Lumen helps you lose weight and keep it off for good with daily feedback.
When your mitochondria use carbs as fuel, they release more CO₂ into your blood, and when they burn fat, they release less CO₂. Lumen analyzes the CO₂% in your breath and determines if you are using mostly fat or carbs for fuel based on the CO₂ concentration.
Lumen’s technology is validated by multiple peer-reviewed scientific studies and is proven to measure metabolism as accurately as the gold-standard metabolic cart. Read the peer-reviewed paper.
Metabolic flexibility refers to how efficiently your mitochondria switch from burning carbs or fats for fuel, depending on their availability and your body’s needs. Being metabolically flexible can be critical for disease prevention and helps with managing weight, improved insulin sensitivity, higher energy levels, better sleep, and even longevity.
Yes, the Lumen device and app work together. The Lumen device measures your metabolism through your breath in real-time and the app provides personalized insights and lifestyle guidance based on those measurements.
After adding your Lumen to the cart, select “HSA|FSA” as your checkout option, currently available only for annual or annual Duo memberships.
At checkout, Flex will prompt you to fill in a short health questionnaire to confirm your eligibility to pay with your HSA/FSA.
From there, enter your HSA/FSA card details and complete your checkout as usual.
If you don’t have an HSA/FSA card, you can complete the checkout with a regular credit or debit card, and Flex will provide you with an itemized receipt to submit for reimbursement.
Lumen is for anyone looking to improve their metabolic health, manage their weight, boost their energy levels, support their workout routine, and live happier and longer lives.
If you are under 16 years of age, pregnant, breastfeeding, or suffer from the following conditions, please consult a medical professional before using Lumen:
Diabetes
Severe asthma
COPD
Additionally, Lumen's nutritional recommendations may not be suitable for people with:
Kidney disease
Cancer
Thyroid disorder
Yes, we offer a one-year warranty from the date the device is delivered to you. If your device or charging dock are damaged by manufacturing defects during that period, we'll fix or replace them free of charge. You can read our full warranty policy here.
* As reported in 2024 Lumen user data analysis