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Today, I’d like to talk about a device that can help you hack your metabolism. It’s called Lumen, and I’ve been using it for over 30 days. I’ll introduce the product and brand identity, go over how to use it, and share my results and honest opinion.

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Lumen Unboxing - Review: 30 Days of Lumen Metabolism Tracker

Lumen arrives in a black box that says ‘Lumen‘ on the front and ‘Hack Your Metabolism’ on the bottom. You’ll find the device inside the box. A purple envelope underneath the device contains a booklet about how to get started. It explains how to download the Lumen app and connect to Apple Health or Google Fit to get a more accurate picture of your health.

Review: 30 Days of Lumen Metabolism Tracker
Review: 30 Days of Lumen Metabolism Tracker

The Discover section covers Lumen levels, tailored recommendations, and Lumen Flex Score. The last section explains how to take care of your Lumen device. Another booklet includes instructions for use and information about opportunities to win a Lumen swag bag full of goodies by sharing your Lumen journey. Also included are a charging dock, travel case, and USB C cable.

What is Lumen?

Review: 30 Days of Lumen Metabolism Tracker

Lumen is the first portable device to accurately measure metabolism by recognizing whether your body is using fats or carbs for fuel based on your breath. 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, indicating the type of fuel your body is using to produce energy. It’s like having a personal nutritionist because the device lets you know what and when to eat to fuel your workout, improve your metabolic flexibility, and support fat burn. You can track your metabolism daily and see how it’s affected by sleep, physical activity, and nutrition. I was even able to track my metabolic flexibility while fasting during Ramadan.

Customized Nutrition & Workout Optimization

Lumen offers customized nutrition and personalized daily meal plans to help you know what and when to eat. I measure my breath in the morning, and they provide a personalized nutrition plan according to my metabolic flexibility and the goals I want to reach. There is also a workout optimization feature. Check before a workout if you have enough energy or need to fuel up. Measure your breath again post-workout to see the impact on your body. This feature is especially useful for those who want to do high-intensity exercises. By knowing how much energy you’ve got left, you can choose the intensity of your exercise accordingly to maximize your results.

Long-Term Benefits

The Lumen device monitors and improves your metabolic health, which can benefit your long-term health. Track your metabolism, sleep, nutrition, and fitness data to provide a Lumen Flex Score reflecting your successes. People who focus on long-term goals tend to have more sustainable and better results. A feature that monitors metabolic health can be quite helpful. When gyms reopened in the UK, I checked my body composition and discovered that my metabolic age was 31, but I’m only 21. When I saw those results, I knew I needed to get it down. I’ve been using Lumen for 30 days, and I’ve seen some interesting results. I’ll talk more about that later, but now I want to go over the brand identity.

How it Started

Lumen is the world’s first device and app that tells you if you’re burning carbs or fat in real-time time based on your breath. Once available only to top athletes in hospitals and clinics, metabolic testing is now available to everyone anywhere. This approach to personalized nutrition began with twin sisters Merav and Michal, Ironman winners and PhDs in physiology. As scientists and athletes, they were passionate about developing a way to provide personalized nutrition but knew the only way to measure metabolism was costly and time-consuming. After four years of hard work and hundreds of beta users, Lumen launched on Indiegogo. It broke the 1 million threshold in weeks and is now leading the way in bringing personalized nutrition to the entire world.

Quite an interesting backstory, in my opinion. The metabolic health benefits include building lean mass, better sleep, a stronger immune system, feeling energized, better weight maintenance, and consistent blood and glucose levels.

Lumen Validation Study

Lumen Validation Study

A study titled Validity of Lumen Handheld Metabolic Device to Measure Fuel Utilization in Healthy Young Adults shows how Lumen‘s estimated metabolic fuel utilization is comparable to the gold standard metabolic card, conveniently providing real-time metabolic information for users anywhere. You can find the study here but be aware that there are a lot of steps involved in studies like this. If you’re not familiar with science, you probably won’t understand it. I’ve studied econometrics at university, so I can analyze most key stats. In my opinion, the data looks fine, but keep in mind that it hasn’t been certified by peer review yet.

How it Works & How to Use it

Lumen‘s proprietary technology determines CO2 concentration in a single breath. The user inhales a fixed volume of air through the device, holding for 10 seconds and exhaling fully. The device consists of a CO2 sensor, flow sensor, LiPoly battery, Lumen PCB, motherboard, and a Bluetooth LED.

Lumen - How it Works & How to Use it
  • To use Lumen, remove the device from the charger and open the lid.
  • Open the Lumen app and press ‘Take a breath to unlock your day.’ It will say sit, relax and turn on your Lumen.
  • The purple light will appear and say, “Let’s go.”
  • You’ll see yesterday’s data unless it’s your first time using Lumen.
  • Breathe in through your Lumen until you see the gray circle on the screen. I had to redo it my first few times because I wasn’t breathing enough.
  • Hold your breath and remove the device from your lips.
  • When the countdown reaches 2, prepare to exhale back into your Lumen.
  • Exhale through your Lumen, keeping the ball within the gray area.
  • Stop exhaling when the ring disappears. The more intensely you exhale, the more the ball will move to the right. The less intensely you exhale, the more it will move to the left.

Once you’ve finished, it will start to analyze your breath. Then, it will give your metabolic flexibility, representing either a lot of fat or carbs. It will show you what steps to take for the day based on your nutrition plan and other key data.

My Thoughts

I think the personal nutrition feature is great for those that don’t know how much or what they should be eating. Lumen provides personalized recommendations and meal plans, so it’s very convenient. I haven’t yet been able to maximize this feature because I was fasting in Ramadan, but I’m certain it could be helpful to many. There’s a feature in this app that allows you to track your metabolism during Ramadan for Sahur and Iftar, in the morning before exercise, after exercise, before eating, after eating, after fasting, and before sleeping. It also allows for custom check-ins, which I’ve used quite a lot over the 30 days. It’s helped me understand my metabolic flexibility so I can act accordingly. It’s quite accurate. 

Lumen can also be used for workout optimization to help you understand whether you’ve got enough energy or you need to fuel up. I always tend to have enough energy for the gym. I didn’t have enough energy when I first returned to the gym after lockdown, but I’ve felt fine since then.

My Results

Lumen My Results

I want to touch on how Lumen monitors and improves your metabolic health. The device gathers a lot of key data to create your Lumen Flex Score,  which allows you to track your health over time and see whether you’re improving or need to make adjustments. The Lumen Flex score takes two weeks to build it up. Since I used it for 30 days, I can’t say much about this particular feature. Regardless, I’ve still seen some amazing results. I’ve been measuring my body composition because I’m making a 60-day body transformation video, so I’ve gathered some key data. When the gym opened, my metabolic age was 31 years old, and it’s since come down to 28 years old. On April 12, 2021, my weight was above 75 kg, but at one point, it was down to 72.4 kg. I’ve gained 0.5 kg since I started using the device at the beginning of April. My fat increased due to the lockdown. On April 12, 2021, it was 13.37 kg. It increased a little bit, but as of May 6, it’s only 10.36 kg. I lost 3 kg of fat over a relatively short period.

I lost over 3.5 kg of muscle during the lockdown, but since I started tracking my metabolism, health, and diet, I’ve been able to gain most of it back. I’ve lost over 3 kg of fat and gained 3 kg of muscle in just a few weeks. By using creatine, I’ve also gained some water weight.


So, do I recommend the Lumen device? Lumen can give you some great insights and key data to help you achieve your goals if you’re dedicated and want to care for your health and metabolic age, but it isn’t a magical tool that will give you magical results. You still have to put in the work and be disciplined. You can have all the right data, but you won’t see any results if you’re not willing to put in the work. For my goals, it was worth it. Without the insights Lumen provides, I don’t think I would have been able to get such amazing results in such a short period. To see the Lumen results of other users click here.

I will include a link for the Lumen device below if you would like to check it out. I hope you found the information useful. Thanks so much. I hope you have a great day, and I’ll see you next time. Bye.

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