Lumen Review UK & Discount – Burn Fat, Lose Fat and Prove It
This is a detailed review of Lumen for readers in the USA and UK, although it starts with a quick summary.
I tried out Lumen, a handheld device that tracks your metabolism by analyzing the carbon dioxide in your breath. It’s a handy tool for people trying to lose weight or athletes wanting to assess their lifestyle choices. Lumen helps you understand how your body burns fat and carbs, which is crucial for those on a weight loss journey or aiming for better endurance.
The device offers personalized nutritional advice, follows a keto-style approach, and syncs with Garmin and Apple Watches. It’s often on sale, and there’s usually a discount if you use an affiliate code. I have a code, THE5KRUNNER, that can be added to ongoing promotions, often saving you over $100. For instance, during Black Friday, using the code the5krunner can get you $100 off and a 50% discount.
CO2 breath analyser
Build Quality & Design
Features, Including App
Openness & Compatability
Lumen Review Verdict: A unique and effective tool for a better metabolism and proving your diet works.
I’ve been using Lumen for over 3 years now, and I can say that it’s the only product that can accurately measure how well your body burns fat and carbs. This is important for losing weight and improving your athletic performance.
Q: What’s the point of losing weight from carbs?
A: None. Anyone can burn carbs. It’s super easy. Burning fat and using it as the default energy source is hard.
Lumen is a small, vape-like device that analyzes your breath to help you understand how your body burns fat and carbs. It’s user-friendly and only takes a minute to get a reading. The device connects to the Lumen app, which not only displays your results but also provides personalized nutritional advice, keto-style tips, and links to Garmin and Apple Watches.
In my experience, Lumen was a valuable tool for my weight management journey. It helped me identify what worked and what didn’t. Making simple changes like avoiding late-night eating and extending fasting periods made a noticeable difference, resulting in a quick 1kg weight loss.
Despite years of endurance training, Lumen revealed that I sometimes burn more carbs than expected. While I can’t vouch for absolute accuracy, the device seemed broadly correct, and its readings aligned well with my blood ketone samples. The information provided by Lumen is practical and actionable, with the app guiding me on what steps to take based on the readings.
Lumen also offers free apps for Garmin and Apple Watches, making it convenient to track your carb and fat-burning status. It was reassuring that my partner, who holds a degree in nutrition, supports Lumen’s dietary guidance.
Overall, I’m very pleased with Lumen and would recommend it to anyone looking to enhance their weight loss or athletic performance.
- Holds you accountable
- Easy and intuitive to use with instant feedback – literally takes one minute
- Good recipe ideas, sensible and straightforward dietary guidance
- Useful apps/widgets for Garmin watches and Apple Watch
- Simple, easy-to-understand metrics
- Supports long-term healthy lifestyle, more than simply weight loss
- Good customer support
- Optionally, your Garmin prompts you to take readings when you’ve just woken up or just completed a workout.
- Lumen only works for readings taken at rest, NOT on the go.
- The results are actionable yet not claimed as medical-grade
Table of Contents (Click to Expand)
Onboarding & Using Lumen
Here are examples of screens you’ll see when connecting Garmin and Lumen. Once you locate your API key (App>Me>Gear Cog>Connect Your Garmin>Connect IQ App !!!), the rest is simple. Just to clarify quickly, a Garmin WIDGET is installed, and you access widgets from your Garmin widget menu, typically reached using the middle left button on a Garmin.
Using Lumen – Basic Usage From This Review
Using Lumen, Let’s Review 5 Essential Ways
Whilst the mechanics are the same for every reading you make with Lumen, there are 5 daily events you might optionally want to let Lumen know more about
- Morning Fasted measurement – Tap the ‘Take a breath’ button in the morning.
- Check-in measurements – Tap the ‘wind’ icon on the upper left-hand corner of the screen. Here you take measurements important to you that you want to track over time such as pre-meals, 60-90 minutes after meals, before going to bed, and before breaking your fast.
- Workout measurements – can be taken by adding a workout to your day – read more
- Breath Signature measurements – Tap on the ‘breathe now’ button on the breath signature card. These are important, pre-tagged measurements targetted at key metabolic states/times of the day
- Boost measurements – available on high-carb Boost days.
Using Lumen to start the day
- Generally, Lumen aims toward a Keto-style diet of low-carb
- Lumen wants you to perform intermittent fasts to continually review and assess your progress
- Lumen adds higher-carb days, perhaps to counteract some of the negative effects of a rigid keto diet.
- Carbs are increased for days when planned workouts might need them. Double-check the carb recommendations if you plan extreme workouts.
The daily nutrition plan is presented straightforwardly. At a fundamental level, you can use it as a guide to adjust your macronutrient consumption patterns. If you’re someone who tracks macronutrient intake meticulously, you have the option to make more detailed changes to your diet in line with the recommendations. Personally, I used it as a general guide.
How to Use The Lumen Food Log
- Easily log meals and ingredients by scanning food labels and barcodes.
- Understand the impact of specific ingredients on your metabolism in real time.
- Determine when and what to eat by measuring the effects of each meal and snack.
- Focus on the nutritional value and macronutrients of foods rather than just calories.
- Monitor how certain food types (macros) affect your exercise, sleep, and fasting routines.
- Import data from other platforms like MyFitnessPal.
In addition to those two standard charts, there are interesting tag-based reports too.
Using Lumen | Review | More Advanced Usage to Hack Your Metabolism
Lumen’s Garmin App
Actual Fat/Carbs in Workouts
Lumen is different and measures your carb/fat usage. The reality you measure will be different from the predictions of software tools like Polar (below), perhaps significantly different.
Here are some screenshots from my Apple Watch app.
Notes on Lumen Usage in this Review
- I suspect that Lumen asks for a 3rd breath when the first two do not agree on the state of your metabolism. On occasions when I didn’t inhale or exhale correctly, a 3rd breath seemed to be required. And on a few of those occasions, I wasn’t convinced by the Lumen score it gave. Over the years Lumen seems to ask less for 3 readings. Maybe I’ve got better at doing it!
- If you hyperventilate before taking a reading, the fat burn score improves. The point of saying this is that if you want meaningful readings you have to perform sensible tests, in the same manner, each time.
- Breath Reading Tips:
- Breathe out before starting, and empty your lungs of CO2-rich stale air.
- Breathe in a little extra air after you have the green ring.
- Between readings, empty and refill your lungs at least twice.
- Don’t hold excess air in your mouth when you hold your breath.
- As part of the research for this review, I found that the consistency of the breath flow rate seems to be important for Lumen to secure a correct metabolism reading. Try to be consistent.
- Lumen requires 5 minutes between sets of readings. I have taken a series of readings separated by 5 minutes, and they can vary by +/- one point on Lumen’s scale. That variance could be down to inaccuracies in the device or in the process I am using. For example, it is possible to start inhaling before using Lumen, and it is possible to hold inhaled air in your mouth… do these make a difference? Possibly, I don’t know. Be consistent!
- If you check the comments section, below, you will see a specific physiological case where Lumen gives incorrect readings, i.e., when you are in a state of deep ketosis.
- I lost 1 kg when I used Lumen for over a month. I’m trying to lose 1 kg more. That loss is a statement of fact measured by my Garmin Index Scale 2 every morning in the same state. I attribute the success to being more aware of food and eating less. I also tended to eat my last meal earlier. #CalorieDeficit.
Lumen – Some Science, Tests & Limitations Brought out in the Review
Lumen has now published peer-reviewed science to support the efficacy of its product. See www.i-jmr.org
Lumen claims this
Lumen’s technology has been scientifically proven to accurately measure metabolic fuel usage when compared to the gold standard (RER) for measuring metabolism in multiple validation studies.
Lumen has this page which cites studies by Lorenz et al and Mor & Mor, both studies have Lumen employees involved and one is peer-reviewed. Having employees involved in the research is not unusual! Nor is sponsored science, this is relatively common practice amongst many of the health/nutrition products you buy. Now that some of the work is peer-reviewed that adds credibility to the claims.
I pointed out to Lumen that their device does not contain an O2 sensor and that an O2 sensor is typical in medical-grade RER devices. They replied,
Measuring the CO2 concentration in one’s exhalation can be used as an indicator to one’s metabolic fuel dynamics according to the following principles:
- Cells that use carbs as fuel produce more CO2 (relative to the consumption of oxygen) compared to when they use fat.
- In a rested condition, the oxygen consumed does not change dramatically, so a subject’s Respiratory Quotient would be mostly represented by changes in CO2 production.
- The CO2 concentration in mix venous blood correlates to the metabolic fuel dynamic.
- The breath-holding technique enables us to determine the CO2 concentration in mix venous blood.
In order to provide fully clear results with Lumen it is therefore important that one is entirely at rest when taking a measurement.
I am not a scientist and have read Lumen’s metabolism studies, linked above, as part of my research for this review. You can make your judgement but they seem reasonable to me in terms of what they say, certainly, more can be done and more can be clarified, that said some of the research is now peer-reviewed.
For me to get a layman’s view of the correctness of the data is tricky. An RER test in a medical lab is an option that I could have done, they take time and are expensive. Handily, I do have a ketone + glucose blood reader from my look at HVMN a while back. So I used that 🙂
Lumen Frequently Asked Questions
A: After nearly 2 years of use, I would say Lumen is accurate for all of us in most normal situations. Lumen publishes scientific papers that claim accuracy in specific circumstances. My own limited and unscientific testing found occasions where Lumen’s results matched results on ketone strips as well as my expected results. Some results didn’t match.
Q: What is a good lumen flex score?
A: 21 is a perfect score and anything over 15 is good. Average scores range upwards from 7.
A: Yes. In my opinion, Lumen is certainly sensing carbon dioxide and inferring carb/fat consumption. It’s not just making the number up. However, I can’t say from my own experience if it has medical-grade results.
A: Yes, kinda. Lumen works primarily with an app on your smartphone. However, there are Apple and Garmin apps that offer extra (free) features on your favourite watch.
A: I’d say it’s good. Lumen has put together a good package of an inhaler and software with some cool insights for athletes and those on diets.
A: The Lumen device is like an inhaler and measures the flow of air and its CO2 content. From that, it infers your fat/carb usage and further assumes you are rested.
A: One alternative to Lumen is the Breezing Starter Kit, I’ve not used it and it has highly indifferent consumer reviews. Trustpilot has some great reviews and feedback on Lumen which, of course, doesn’t prove it’s scientifically accurate but it does show that users are generally very happy with the product. Foodmarble is another alternative that analyses the hydrogen content of your breath. However, as far as I know, there are no consumer-grade competitors to Lumen that measure fat burn from breath signatures.
Q: What were previous generation Lumen devices?
A: There has only been one version of Lumen. This is the original version and there is no planned replacement or upgrade that I know of.
These specs are here for completeness and I’ll draw your attention to a couple of features not covered elsewhere in the Lumen Review like a maximum of 14 days of battery life and the need for iOS/Android version 8.
|Lumen Technical Specifications|
|iOS compatibility (iOS 8 and higher)||iPhone 6 and more recent|
|Android compatibility (8.0 and higher)||Recommended higher than 720 x 1280 pixels|
|Bluetooth connectivity||Bluetooth Low Energy needed|
|Application connectivity||Apple Health Kit, Google Fit|
|Operating temperature:||15°C to 40°C (59°F to 104°)|
|Storage temperature:||-30°C to 70°C (-22°F to 158°)|
|Single battery charge lasts||Up to 14 days in normal use|
|Battery||Lithium polymer battery|
|Lumen device dimensions||102mm x 41.4mm x 33.3mm|
|Lumen device Weight||75g|
|Docking station dimensions||14.5mm x 79.5mm x 68mm|
|Docking Station Weight||145g|
|Charging Connections:||USB-C (cable provided)|
Lumen has some great resources on its app but for those of you interested in learning more before you buy it their site is a great place too.
Link to: Lumen Knowledge Base
Lumen – A Quick Take Out
Lumen Metabolism Review – Price, Discounts & Availability
The Lumen device is now available for a frequently discounted price below the rrp/msrp of $299/£299/Eu299. Nutritional guidance and other app features are accessed by a new, cheaper, subscription at $19/£19/Eu19 a month.
Currently, my code THE5KRUNNER gives you $/£/Eu50 off, 1-month free subscription and free delivery in most countries.
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 the Amazon link below if/when Lumen is listed there.
I’ve got an ADDITIONAL code for readers of this site. That code is THE5KRUNNER 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)
Order HERE, or click one of the Lumen images and use the code THE5KRUNNER
This content is not sponsored. It’s mostly me behind the labour of love which is this site and I appreciate everyone who follows, subscribes or Buys Me A Coffee ❤️ Alternatively please buy the reviewed product from my partners. Thank you! FTC: Affiliate Disclosure: Links pay commission. As an Amazon Associate, I earn from qualifying purchases.