4.5 stars
Over 6K reviews

You have the power to change your metabolism.

Reach your weight and fitness goals with real-time metabolic measurements and personalized recommendations.
$359
$199
or $16.58/mo with
Get Lumen
Metabolism Tracker
4.5
(6K reviews)
$199
Get Lumen

As seen on

Backed by science,
trusted by 300K users
around the world

70M+
breaths taken around the globe
10
years of changing lives
23
research partnerships

What Lumen can do for you

Struggling with weight loss?
Avoid second-guessing when and what to eat by measuring your metabolism with Lumen.

Lumen CO₂ sensor

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Lumen CO₂ sensor

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Lumen CO₂ sensor

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Not seeing workout results?
Fuel smarter with insights to enhance performance, burn fat, and build muscle.

Lumen CO₂ sensor

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Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Dealing with low energy and fatigue?
Unlock more energy with lifestyle strategies based on your real-time biofeedback.

Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

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Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Intermittent fasting leaving you “hangry”?
Find your optimal fasting window based on your unique metabolism.

Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

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Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Lumen CO₂ sensor

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam eu turpis molestie, dictum est a, mattis tellus. Sed dignissim, metus nec fringilla accumsan, risus sem sollicitudin lacus, ut interdum tellus elit sed risus. Maecenas eget condimentum velit, sit amet feugiat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Praesent auctor purus luctus enim egestas, ac scelerisque ante pulvinar. Donec ut rhoncus ex. Suspendisse ac rhoncus nisl, eu tempor urna. Curabitur vel bibendum lorem. Morbi convallis convallis diam sit amet lacinia. Aliquam in elementum tellus

Transforming lives,
one breath at a time

Excellent
4.5 out of 5
“I’m so glad I found Lumen because I’ve been struggling with my weight for years, and now I am reaching goals I never thought I would! I can actually see myself reaching my final goal, which I haven’t been able to come close to in over 40 years! I really enjoy using Lumen! It’s positive motivation!”
Sher H.
“I’ve tried all kinds of programs and apps, but I needed something personalized that provided consistent feedback while also not having an ’eat whatever just hit the macros’ attitude. Lumen fits those needs perfectly. I love checking in on my metabolism throughout the day, and it’s helping me rebuild my relationship with food.”
Indu I.
“It’s great for understanding how your metabolism reacts to all kinds of stimuli like diet, exercise, stress, alcohol, or just overeating. It helped me understand how important it is not to eat past 7 pm so your body can digest your last meal and switch to burning fat during sleep. Really helped me to stop snacking at night.”
Oscar M.
“Lumen is helping me understand deeper concepts about my body and what it goes through when I’m not eating enough or when I’m not slowing down, and that the trope of ’eat less, exercise more’ is probably the key ingredient in our societal stress epidemic. I’m learning I have to slow down and eat a lot more. I love that.”
Tracy B.

Start your journey

Lumen gives you real-time metabolic insights to optimize nutrition, energy, and performance—backed by leading research.
Buy now

How Lumen works

Lumen measures your metabolism through your breath, giving you personalized insights to make the right choices for your body.

Breathe into your Lumen

All you need is one breath to measure your metabolism.

Get real-time metabolic feedback

Find out whether you’re burning carbs or fats for energy.

Make the changes that work for your body

Receive a daily tailored nutrition
plan with lifestyle and metabolic insights to reach your health and wellness goals.

Lumen’s research partners

Cutting-edge hardware meets innovation

Lumen's accuracy is on par with the metabolic cart, the clinical standard for metabolic measurement.

Cutting-edge hardware meets innovation

Advanced science

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.
Lumen’s unique technology has been validated to match the gold standard for metabolic measurement, giving you access to lab-level insights from your home.

Long-lasting battery

The advanced lithium-ion polymer battery provides rapid charging and lasts for ~10 days of use.

Validated by peer-reviewed scientific research

Backed by science and trusted by researchers.

Validated by peer-reviewed scientific research

Lumen’s tech is peer-reviewed to be on par with the gold standard for measuring metabolism (RER). Read more.

Lumen was found to reliably test metabolic fuel usage pre- and post-meal. Read more.

Lumen’s research found that people with better metabolic flexibility process carbs more efficiently and are less likely to store carbs as fat. Read more.
Lumen’s research demonstrated that women experience increased carb burn during the first half of the menstrual cycle and increased fat burn in the second half. Lumen’s study also indicated increased carb burn for menopausal women not using HRT, compared to those with HRT. Read more.

In a study published in Obesity Facts, Lumen was found to help reverse pre-diabetes by promoting metabolic flexibility through the use of both the device and app. Results showed a decrease of 0.27% in HbA1C and 3% in body fat. Read more.

The first steps of your health journey with Lumen

In just one breath, you’ll uncover how your body is using fuel—whether you’re burning carbs or fat. It’s the first step to understanding your metabolism.
With daily metabolic insights, a personalized nutrition plan, and AI-powered food logging, you’ll start making choices that support your health goals.
Feel the shift—many people experience higher energy, improved metabolic flexibility, easier weight loss, and better sleep. Your body is learning to adapt, and so are you.

Health shouldn’t feel like a game of chance.
Get a clear picture of what works best for your body and where to start.

Lumen metabolism tracker
$359
$199
Get Lumen today

Lumen’s most frequently asked questions.

How does metabolic flexibility improve my health?

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 important for disease prevention and helps with managing weight, improved insulin sensitivity, higher energy levels, better sleep, and even longevity.

​​How does Lumen measure my metabolism?

When your mitochondria use carbs as fuel, they release more CO₂ into your blood; 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 has been validated to match the gold standard for metabolic measurement with an at-home, handheld device.

Is Lumen’s technology validated?

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.

Do I need the Lumen device to use the premium app features?

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.

Can I use Lumen with the keto diet?

Lumen provides valuable insights for those switching between carbohydrate and fat burning. In ketosis, however, ketones complicate the readings, and you may not see a clear indication of being in fat burn when taking measurements. The higher CO₂ levels from ketone metabolism can suggest carbohydrate use, even when you mainly rely on fats for energy.