Lumen Raises $62 Million in Series B Funding to Advance Metabolic Health Platform Serving Over 2 Million Users Monthly

According to estimates by the World Health Organization (WHO), as of 2016, there were 1.3 billion overweight adults and 650 million obese adults worldwide (accounting for approximately 13% of the global adult population). Obesity not only affects physical appearance and daily life but also triggers metabolic syndrome, leading to various health problems.

Obesity is closely related to the body's metabolism and immune function. Obesity can cause chronic inflammatory responses, increasing the likelihood of metabolic syndrome.

Good metabolic health is defined as having blood glucose, triglycerides, beneficial cholesterol (high-density lipoprotein), and blood pressure—all four indicators—along with waist circumference, within normal ranges without the use of medication. Poor metabolic health increases the risk of serious conditions such as type 2 diabetes and heart disease.

Israeli company Lumen has developed a portable device that measures metabolism through breathing, determining the user's metabolic rate based on the concentration of carbon dioxide (CO₂) in their breath.

On December 1, the company announced that it had secured $62 million in Series B financing, led by Pitango Venture Capital, with participation from Hanwha Holdings, Resolute Ventures, RiverPark Ventures, Unorthodox Ventures, Almeda Capital, and Disruptive VC.

Lumen plans to leverage this funding round to expand its global footprint, enhance the functionality of the Lumen app, and strengthen research collaborations with academic institutions.

Lumen, founded in 2014 and headquartered in Tel Aviv, Israel, is a digital health and wellness company. The company pioneered the first handheld portable device capable of accurately measuring metabolism.

Michal Mor, Co-founder and Head of Product Science at Lumen, holds a Bachelor’s degree in Medical Laboratory Science, a Master’s degree in Physiology, and a Ph.D. in Cardiovascular Physiology from Ben-Gurion University.

First row, from left to right: Merav Mor, Michal Mor. Image credit: Amit Sha'al

Michal Mor and her twin sister, Merav Mor, have been Ironman triathletes for many years. During their triathlon training, they found it difficult to determine whether their bodies required additional carbohydrates to replenish energy stores. While pursuing their Ph.D.s at Ben-Gurion University, they recognized the significant gap between academic knowledge and practical application, which inspired them to develop the concept of measuring metabolism through breath analysis.

There are two common methods for measuring metabolism: one is measuring the RQ (Respiratory Quotient), which involves blood sample collection and typically requires expensive, time-consuming tests conducted in hospitals or clinics; the other is measuring the RER (Respiratory Exchange Ratio), which indirectly calculates the consumption of carbohydrates and lipids for energy production by measuring carbon dioxide (CO₂) production and oxygen (O₂) uptake.

“The science is already there,” said Merav Mor. “The technology for measuring metabolism is not new. Hospitals and testing facilities have been offering metabolic measurement services since the 1960s. However, this method has several drawbacks, and Lumen has made the test much easier.”

Thus, in 2014, Michal Mor co-founded Lumen with three of her old friends and several entrepreneurs.

In 2016, the Lumen device entered public beta testing. In 2018, Lumen launched on the crowdfunding platform IndieGoGo, raising $2.3 million in 40 days, exceeding its funding target by 27%. In May 2020, Lumen was officially released to the general public.

Nowadays, Lumen enables everyone to monitor the sources and status of their body’s energy in real time. By leveraging Lumen’s science-based approach, individuals can manage their nutritional intake and lifestyle to achieve goals such as weight loss, improved athletic performance, or diabetes prevention.

Michal Mor stated, “We hope that one day, measuring metabolism will become as routine as brushing your teeth. Everyone will be able to manage their lifestyle based on their individual metabolic status.”

Lumen aims to help users “hack” and retrain their metabolism, enabling them to maintain “metabolic flexibility.”

“Metabolic flexibility” means the body can more efficiently switch between burning carbohydrates and fat. Metabolic flexibility can be achieved through time-restricted eating (such as intermittent fasting), exercise, controlling macronutrients, or balancing protein, carbohydrate, and fat intake.

The Lumen team believes that this flexibility can improve insulin sensitivity and help the body burn fat more efficiently. It can also stabilize blood glucose levels, resulting in increased energy and reduced appetite.

The RER indicator can indicate whether the body relies on fat or carbohydrates for energy. A low-carbohydrate diet prompts the body to use stored fat as its primary metabolic fuel source, resulting in a low RER value; whereas a high-carbohydrate diet causes the body to preferentially utilize available carbohydrates from the digestive system, along with small amounts of fat, as metabolic fuel, resulting in a high RER value.

Lumen is a handheld device equivalent to RER. Lumen uses RER as the core data point, determining the CO₂ concentration in a user’s single breath through a CO₂ sensor and a flow meter.

Measuring CO₂ concentration requires the user to inhale a fixed volume of air through the Lumen device, hold their breath for 10 seconds, and then exhale completely. Users need to repeat this process at different times throughout the day to obtain accurate data.

Lumen assesses the user's metabolic rate based on measured CO₂ concentrations. Human cells produce more CO₂ when metabolizing carbohydrates than when metabolizing fats. Therefore, a high CO₂ reading indicates that the body is burning carbohydrates, while a low CO₂ reading indicates that the body is burning fat.

After the user breathes into the device two to three times, the Lumen app provides a score from 1 to 5, simply indicating whether the body is primarily burning fat (1–2) or carbohydrates (4–5). A score of 3 signifies a mixed utilization of fat and carbohydrates for energy. After four weeks of measurements, users receive a Lumen Flex Score, which rates their metabolic flexibility.

Lumen creates a daily plan based on the user’s score and recommends consuming low-carbohydrate, moderate-carbohydrate, or high-carbohydrate foods.

Researchers at the San Francisco State University Exercise Physiology Laboratory used Lumen and the gold-standard metabolic cart method (RER measurement) to assess metabolic fuel utilization, conducting a comparative validation of the two approaches. The study demonstrated a high correlation between the measurements obtained by both methods, indicating that the Lumen device can accurately evaluate the utilization and changes in the body’s metabolic fuels.

In August 2021, Lumen transitioned to a subscription model, under which subscribers receive Lumen’s portable testing device and 6 to 12 months of access to its mobile application.

Users simply need to breathe into the device, and Lumen will analyze whether the body is burning fat or consuming carbohydrates.

Lumen develops continuous, personalized solutions based on users’ food preferences, exercise details, and sleep habits, including analyzing metabolic flexibility, providing education on metabolism, and offering dietary and exercise recommendations.

The number of people using Lumen to improve their metabolism has increased by 500% in just the past year, with the company stating that its annual revenue has reached tens of millions of dollars.

Co-founder Michal Mor stated, “Most Lumen users aim for weight loss, but we hope to expand our audience to include those focused on maintaining overall health.”

In November 2020, Lumen gained recognition from wearable device giant Garmin, marking the first integration of their products. Data from both companies showed that Garmin users measured their metabolism using the integrated solution over 10,000 times post-exercise within the first three months. In May 2021, Garmin announced a Phase II integration with Lumen’s devices and app to incorporate metabolic data. This latest phase enables Garmin users to directly correlate their metabolic data with the body energy monitoring feature.

In June 2021, Lumen partnered with the UFC, the world’s premier mixed martial arts organization, to become the official metabolic tracker for the UFC Performance Institute.

In September 2021, Lumen launched its iOS app, becoming the only application in the Apple Watch Store capable of measuring and tracking users’ metabolism. The app enables users to analyze their breath using the Lumen device and view the results directly on their Apple Watch. However, the initial version of the Lumen iOS app lacked a food logging feature, requiring users to rely on third-party applications such as MyFitnessPal or Calory to track personalized nutritional recommendations provided by Lumen. In March 2022, the Lumen iOS app was updated to include a food logging function, with support for importing data from applications like MyFitnessPal.

To date, the Lumen app has established partnerships with Apple HealthKit, Google Fit, and Garmin.

Lumen has been dedicated to clinical research on health issues. Over the past year, the company has collaborated with research institutions such as Purdue University’s Whistler Carbohydrate Research Center, the University of Toronto’s Faculty of Kinesiology and Physical Education, and ARU Cambridge.

“Understanding the impact of nutrition, exercise, sleep, and stress on metabolism is crucial for maintaining healthy physical and mental well-being,” said Daniel Tal, CEO and co-founder of Lumen. “Our team is delighted to see people taking better care of their ‘body engine’ (metabolism). Over the past year, Lumen users have gained awareness of what foods they should eat and which habits they should change or maintain.”

Currently, Michal Mor is developing a new feature for Lumen—the menstrual cycle function. This feature will display the phased changes in women’s metabolism during their menstrual cycles. Michal Mor aims to leverage the technology possessed by the Lumen team to address the specific needs of women and their bodies.