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Lumen Review Roundup 2023 – Is It Worth Buying?

Lumen is making waves in both health and tech circles for being the first hand-held device to accurately measure metabolism of an individual within seconds. Unsurprisingly, reviews have started pouring in, evaluating the gadget on everything from design and performance to cost and value for money.

The metabolism tracker seems to fare well across the board in terms of functionality, but falls short in factors like affordability and ease of use- begging the age-old question, is the Lumen worth buying? To help you make the best decision, we’ve curated a detailed breakdown of what the device offers its users based on top reviews from reliable sources.

Before getting carried away in the merits and demerits of this innovative new gadget, however, it is best to first try and discuss exactly what the Lumen is and how it works.

What is Lumen?

The Lumen device comes with a dedicated app to help users make sense of their data | Mashable

Marketed as a gadget designed to help “hack your metabolism”, Lumen is a biotechnology device which measures the metabolism of an individual to help them make better decisions about their meals, workout schedule, and general lifestyle.

Users of the device are told to breathe into it at regular intervals during the day so that Lumen can form a profile of what they ate. Lumen then measures the CO2 concentration in a single breath using a flow meter and a CO2 sensor.

This reveals the kind of energy source a user’s body is generating. It then uses this information to suggest a meal plan detailing the approximate number of portions of carbohydrates, fats, and proteins that should be eaten to maintain optimal health.

At its core, Lumen aims to make it easy for users to improve their health long-term. Using this gadget, customers can both gain a deeper insight into how their own body works as well as be guided about what steps to take to keep themselves on track with their fitness goals.

Review Roundup

Critics evaluated the Lumen based on multiple criteria. We’ve summarized their findings into four broad categories, namely design, price, functionality, and the effectiveness of the device’s companion app of the same name. Let’s discuss how the device fared in each category individually.


The Lumen must be charged periodically to continue using it effectively | The Medical Futurist

The Lumen is compact, handheld, and most importantly, portable- allowing users to store it in their pocket or purse easily when on the go. Jamie Carter from Tech Radar praised the finish of the product, calling it “a refined piece of kit that feels expensive”. 

Kimberly Dawn Neuman at Tomsguide echoed his sentiments, stating she “continued to be impressed by the quality of the actual device”, moving on to say “it’s really solid and well constructed”.

Both reviewers were quick to comment on the uncanny resemblance of Lumen to a typical vape pen or e-cigarette. However, Midea Giordano at WIRED reminds us that this may not be a bad thing- as its appearance “could make it go almost unnoticed if you were measuring your breath in public”. New users embarrassed of breathing into the device while in the middle of a crowd may hence feel more comfortable because of this similarity in design.

Like most technological devices, the Lumen needs to be charged periodically to keep it up and running. It comes with a USB-C cable-powered charging base which can keep the device charged for up to two weeks. It also features a magnetic cap to keep the area around the mouthpiece clean and can supposedly be used by multiple people given they have their own profiles on the app- though Caroline Lubinsky says what we’re all thinking in her review on Garage Gym, stating “I don’t think I’d want to share a device I’m blowing air into multiple times per day with anyone.”


You can buy the Lumen at three different price points depending on the plan you opt for

The Lumen markets itself as a revolutionary device previously only available to only a select few professionals in the healthcare sector. The price they charge for bringing the service to individual consumers and that too at a size that can easily be stored in a pocket is, understandably, on the high end.

Users of Lumen must pay for both the device itself as well as an ongoing monthly subscription that caters to the services being provided through the app. WIRED’s Media Giordano states “at $350 it’s definitely a luxury and not something I’d typically spend my money on”, though she does believe it to be ultimately less expensive than a nutritionist.

TechRadar’s Jamie Carter agrees with the general sentiment but offers a silver lining, saying “yes, Lumen is an expensive device, especially with the attached subscription, but you do get a 30-day trial period during which you can cancel the whole thing and send it back for a full refund.”


The Lumen device is essentially a breathalyser which requires regular breath tests to function | Digital Trends

Lumen works by analyzing the CO2 breathed out by users into the device. For an accurate diagnosis, a four week commitment is required by the app in which users need to breathe into the Lumen at multiple specified intervals a day. At the end of the month, they will be given a Flex Score which will essentially be a measurement of how flexible your metabolism is.

Unfortunately, this analysis is not as easy as it sounds, as many users complained of having to retake the breath test multiple times before it was accepted. “When you’re asked to do it multiple times a day, it gets quite dominating,” stated Jamie Carter at Tech Radar, going on to say that “Lumen is needy.”

Once you do get the hang of things and start logging in accurate breath tests, the Lumen is fairly accurate in determining what your body is using as fuel and what you should focus on in your next meal. For example, guiding towards protein after having a carb-heavy meal.

This can be especially helpful if you’re on a specific diet and want to see how it may be affecting your body. Caroline Lubinsky at Garage Gym talks of her experience while on the keto diet, reflecting on how “Lumen is definitely a cheaper way to test for ketosis than ketone strips in the long run”.

One point to keep in mind however is that Lumen is a lot more work than just a few breaths per day. To gain most accurate readings, the Lumen advises manually logging in every meal down to the very last gram of macro consumed. Neumann at Tomsguide cautions against this, stating “if counting grams of carbs isn’t something you want to partake in, you’re probably not going to see much of a shift in your results over time, especially since Lumen seems to be set up such that you get a “better” score if you’re burning more fat than carbs.

Companion App

A dedicated app is used in conjunction with the Lumen device to help make sense of the data being inputted | 9to5Mac

All of the data collected by Lumen is displayed to the user through its dedicated companion app of the same name. The app offers detailed tutorials for breathing into the app, which can definitely be difficult to get the hang of. Jamie Carter at Tech Radar calls the app “excellent, never once crashing during our lengthy review.” He goes on to further say “It’s also incredible at holding the user’s hand”- a necessary feat for such a revolutionary device.

In addition to tutorials, the app features a learning section for users to gain particular insight on a range of topics related to nutrition and health. It also offers detailed meal plans along with several alternatives for certain ingredients based on preference or diet, for example if you happen to be vegetarian or vegan. Midea Giordano at Wired acknowledges the convenience of this, stating, “It’s nice to have everything in one place, so you don’t have to go searching for your own interpretations of meals. In time, it would be nice to see a larger, revolving menu of meals.”

Final Verdict

Lumen might truly help some individuals become more aware of what they are putting into their bodies. It brings about a competitive spirit that motivates users to stick to the app’s macros and pay attention to what they are eating. It would be advisable to opt for it if you’re looking to slim down or improve your diet and the expense of the monthly subscription doesn’t concern you.


Kamil Anwar

Kamil is a certified MCITP, CCNA (W), CCNA (S) and a former British Computer Society Member with over 9 years of experience Configuring, Deploying and Managing Switches, Firewalls and Domain Controllers also an old-school still active on FreeNode.