Lumen gets a peer-assessed nod
Must-read: Lumen Review & Discount
Athletes and those on a diet want to increase the %age burn towards fat as a fuel source. Before Lumen there was no easy or cheap way to measure that.
Lumen estimates metabolic fuel usage, ie the degree to which you are burning fats and carbs as fuel sources. However, it does so by only measuring CO2 during resting periods, which contrasts with the significantly more expensive mechanisms used in laboratories that also measure oxygen levels. Leading us to ask, “Does Lumen work?” In answer to that, Lumen’s original science showed that their product did work, and my own experiences, although non-scientific, suggested that it seemed to be ‘about right’.
However, one of the criticisms levelled at Lumen was that it lacked peer-reviewed science to support its claims. Fair enough. There is a lot of health and sports tech that has never been peer-assessed, such as some of the optical HRMs on your wrist.
Earlier this month a peer-assessed study was announced – link to i-jmr.org.
Conclusions: This study shows the validity of Lumen for detecting changes in metabolic fuel utilization in a comparable manner with a laboratory standard metabolic cart, providing the ability for real-time metabolic information for users under any circumstances.
Interact J Med Res 2021;10(2):e25371
So if you were unsure about Lumen’s accuracy, this news might sway a few doubters. In any case, Lumen gives you a 30-day money-back guarantee.
Lumen Metabolism
Track actual carb and fat burn.

Lumen Metabolism Review – Price, Discounts & Availability
Lumen is in stock and available directly from the manufacturer with a 30-day no-quibble guarantee and there are usually discounts to be found. I’ll add in the Amazon link below.
Lumen is often on sale eg now (Jan2020) for $279/£279 (rrp$349/£349…probably Euros are the same discount)
I’ve got an ADDITIONAL code for readers of this site. That code is FATBURN and that will give you an EXTRA $30/£30 off AT ANY TIME. ie both offers work together. This code should work over and above any discounts Lumen offers directly.
You can get a further 10% off if you order two (ie 3 deals together in one)
Note the LUMEN SALE and the 2-for-1 deals should be automatically applied in Lumen checkout. My discount code: FATBURN will need adding manually.
Order HERE, or click one of the Lumen images and use the code FATBURN
Lumen Metabolism
Track actual carb and fat burn.
I think your study link is broken. An actual article can be found here. Full PDF is here.
Not to be a nitpicker or anything, but it looks like all we really got is a yet another company-designed and sponsored study at a second tier state school, done on a handful of young and healthy people, and published in a journal that’s stretching a definition of peer-reviewed a bit. In my modest opinion, this may be the same level of scientific rigor as Runner’s World study if beer helps post-run recovery.
It remains to be seen how applicable the study is to both elite athletes and overweight couch potatoes from the real world.
much of what we use is not even based on this level of peer-reviewed science.
where are the peer-reviewed Firstbeat papers? I’m not meaning to decry them but for some products we seem to want peer-reviewed studies to the Nth level and others we just accept.
i sent Lumen back after 3 month of use, i think it’s not made for Multisport like Duathlon, it’s a Beta Product, Garmin Integration not work perfect.
If I would follow the dietary suggestions, I would be underweight in a short time, strangely enough, myFitnesspal can do that better
you can get good at shorter duathlons with just training your threshold. i have a top 5 itu AG result to prove it. maybe something like LKumen to make me focus on fat burning would have made me do better…i will never know
yeah I agree about Lumen’s dietary suggestions and in my review, I do point out the need to carb it up a bit more.
at least this study gives us some confidence in Lumen’s readings