Samsung’s Antioxidant Index on Galaxy Watch8 transforms what once seemed like science fiction into everyday technology. In five seconds, a thumb scan returns carotenoid levels – the industry’s first measurable nutrition index.^[1]

By miniaturising lab-grade sensor technology, the feature turns your diet into an actionable metric for healthier aging. Establishing this new benchmark in wearable health tracking required years of intensive R&D, countless prototypes and unwavering grit.

Breaking New Ground in Nutrition Tracking

Back in 2018, Samsung saw a critical gap in wearables: we could count steps and calories, yet there was no simple way to measure how our diet impacted our health. Deeper nutritional insights were locked behind expensive and time-consuming lab tests, out of reach for many people.

As people live longer, the focus is shifting from simply increasing lifespan to improving the quality of those additional years.

“In this context, antioxidation naturally gains attention as a method to slow down aging,” explains Dr. Hyojee Joung, a Seoul National University public health nutrition expert who guided parts of the tech’s development. “If antioxidant management is neglected, Reactive Oxygen Species (ROS) accumulate in the body, increasing the risk of chronic diseases such as cardiovascular disease, diabetes and cancer.”

This realisation made antioxidants the cornerstone of Samsung’s mission. Engineers and scientists focused on carotenoids – key antioxidants and proven indicators of fruit and vegetable intake – to create a device small enough to sit on your wrist, yet powerful enough to turn complex antioxidant data into simple, actionable health insights for everyone.

The first prototype of the spectroscopy-based antioxidant sensor

A clinical-ready version of the sensor

A prototype designed for use in skincare products

Challenge #1: How to Shrink the Lab-Grade Sensor Technology

From day one, the dream of a nutrition-tracking wearable hit an immediate snag: traditional methods for measuring carotenoid levels like Raman spectroscopy are laser-based, non-invasive and precise, but rely on bulky machines that are far from wearable. So, the team’s first mission was to shrink the lab-grade tech into a coin-sized sensor.

After seven years of rigorous testing and optimising since the first prototype, the team developed the miniaturised sensor, a groundbreaking tech that combines multi-wavelength LEDs with a custom photodetector array to provide carotenoid readings in a compact design.

“Our breakthrough was integrating reflectance spectroscopy with LEDs, which allowed us to miniaturise the technology while maintaining a high level of accuracy,” explains Jinyoung Park, a developer from Digital Health Team at Samsung Electronics.

Antioxidant sensor LED-PD sensor modules

Unlike lasers, which emit a sharp, narrow wavelength, LEDs emit a broader wavelength range. By analysing how much light is absorbed by the skin at multiple wavelengths through photodiodes,^[2] the watch estimates carotenoid levels with impressive accuracy. The advanced algorithms that continuously calibrate in real-time also support precision while delivering personalised insights to each user.

The LED-PD Watch prototype testbed

Challenge #2: How to Ensure the Tech Reaches Everyone

Creating a coin-sized carotenoid sensor was a major milestone, but the next challenge was ensuring it could work accurately and reliably across diverse skin types, making it truly accessible to everyone.

To overcome challenges like melanin interference in darker skin tones, Samsung’s engineers opted to use the fingertip for measurements since it has the least melanin across all ethnic groups. They also added simple tweaks, like light fingertip pressure during scans, which helps temporarily reduce blood flow and hemoglobin interference, making the results more accurate.

Extensive trials conducted at Samsung Medical Centre, included hundreds of participants, validating the sensor’s performance. This paved the way for a feature that seamlessly transitioned from the lab to users worldwide, offering an inclusive solution designed for everyday life.

How It Works

Carotenoids are the natural red, yellow, and green pigments found in fruits and vegetables. Since our bodies can’t produce carotenoids on their own, the levels stored in the body offer a clear snapshot of how much fruit and vegetables someone has been eating.

This is where your Antioxidant Index score comes in, reflecting your carotenoid levels based on these categories:

• Very low: Less than 50% of the daily WHO recommendation of 400g per day.
• Low: Between 50%–100%.
• Optimal: 100% or more.

“Skin carotenoids metabolise and accumulatein tissues gradually, so short-term changes in fruit and vegetable intake won’t immediately appear in the score,” explains Dr. Hyojee Joung. “Our research shows that increased carotenoid intake leads to a meaningful rise in skin carotenoid levels after about one to two weeks, making the Index a valuable tool for tracking consistent, long-term dietary habits.”

Lifestyle factors like sleep quality, stress levels, and physical activity also influence the Index, making it a well-rounded indicator of overall health. Paired with other Galaxy Watch8 features like sleep coaching, activity tracking and Vascular Load monitoring, the Antioxidant Index offers a holistic view of your well-being, empowering smarter decisions for healthier aging. ^[1]

The Antioxidant index feature measures carotenoid levels in seconds with the sensor on the back of the Galaxy Watch8 and provides additional nutritional insights on paired Galaxy smartphones.

Your Health, Reimagined

“New wearable sensors can play a role in helping people build healthy eating habits by tracking and encouraging sufficient daily intake of fruits and vegetables,” says Professor Yoonho Choi from Samsung Medical Centre. “Over time, this simple practice can help prevent some cancers and other age-related diseases, making it a very effective way to support long-term health.”

Antioxidants are an emerging area of focus, but research has been limited due to the challenges of accurate measurement. Galaxy Watch8’s Antioxidant Index goes beyond current industry developments and delivers meaningful innovation.

Samsung’s ability to measure antioxidant levels with precision, acknowledged by experts as a benchmark for future research, represents a breakthrough in health monitoring. By helping users identify risks early and take proactive steps towards better health, Samsung is paving the way for a smarter, more proactive approach to wellness and redefining the role of wearables in preventative healthcare.

^{[1] The Galaxy Watch 8 series is not a medical/therapeutic device. It solely intended for fitness and wellness purposes only and is not intended for use in detection, diagnosis, treatment of any medical condition. The result is for your personal reference only. Please consult a medical professional for advice.}

^{[2] Photodiodes are semiconductor devices that convert light into electrical signals.}

Samsung Electronics participated in World Sleep 2025, joining industry experts and leaders at the biennial international forum dedicated to advancing global sleep health. Samsung showcased its latest advancements in wearable technology, which work seamlessly with the Samsung Health app to empower consumers in their pursuit of healthier and more balanced lives.

Visitors to the Samsung booth were offered an interactive experience to explore how its innovations can support better sleep and health. Attendees were given the opportunity to complete a short sleep survey to discover what type of sleeper they are – to determine their distinct sleep pattern with unique characteristics related to sleep duration, consistency and awake time. The booth also highlighted the transformative potential of the Samsung Health Software Development Kit (SDK) — a powerful suite of developer tools that enables the secure and consent-based use of health data. SDK is a testament to Samsung’s continuous integration of technology into daily life to foster better health outcomes, particularly in the critical area of sleep.

“Sleep is a cornerstone of health, and at Samsung, we are committed to helping people understand and improve it,” said Jong Min Choi, Vice President (VP) of Health R&D, Samsung Electronics. “At World Sleep 2025, we are proud to demonstrate how our innovations can translate complex biometrics into clear, actionable insights that help individuals take meaningful steps towards better everyday well-being”.

During the Samsung symposium which focused on wearables and next-generation technologies, VP Choi discussed the advancements that Samsung has made in delivering solutions that support health and wellness, detailing how its innovations are shaping the future of health.

Uncovering Health Habits in Southeast Asia and Oceania

Consumer research conducted by Samsung across Southeast Asia and Oceania (SEAO)^[1] has shed light on some critical challenges concerning sleep and overall health. The findings indicate that adults in the SEAO region average only about 6 hours and 50 minutes of sleep per night, less than the seven to nine hours generally recommended by the National Sleep Foundation^[2]. A deeper dive into the research reveals that 28% of respondents reported “an inability to switch off” as a key concern they have for sleep.

The survey also highlighted that stress levels are notably elevated among working adults aged 36 to 45. This demographic faces unique pressures, and the burden is particularly pronounced for women –  many who are managing the demanding dual responsibilities of their careers and family life.

These insights underscore the need for greater awareness as well as practical and accessible health and sleep solutions, reinforcing the importance of Samsung’s efforts to develop products and features that provide insights on sleep, stress and fitness for better and more personalised wellness management.

Leading the Charge in Sleep Health

One of Samsung’s latest innovations in personalised health experiences is the Galaxy Watch8 Series, newly launched in July 2025. This series introduces a suite of advanced features designed to elevate the effectiveness of sleep tracking and coaching.

The Bedtime Guidance feature offers personalised sleep recommendations that are crafted based on the Two-Process Model of Sleep Regulation – a well-established scientific framework that describes the interaction between homeostatic sleep drive and circadian rhythms. By leveraging this model, Bedtime Guidance^[3] empowers users to proactively establish healthier sleep routines, promoting more consistent and restorative sleep patterns.

Beyond helping users build better sleep habits, the Galaxy Watch8 Series offers a Sleep Apnea^[4] feature which enables users over the age of 22 who have not been diagnosed with sleep apnea to detect signs of moderate to severe obstructive sleep apnea (OSA) over a two-night monitoring period, a common and chronic sleep condition that often goes undiagnosed and untreated. When users are alerted to signs of sleep apnea, they can take steps to seek medical attention and management for the condition, thereby mitigating potential long-term health risks.

In addition to helping users sleep better, the Galaxy Watch8 Series incorporates Vascular Load^[5] monitoring to track stress levels of the vascular system during sleep. When sleeping, stress levels should naturally dip although excessive fluctuations can negatively impact cardiovascular health. By providing lifestyle information such as sleep, stress and activity, the insights from Vascular Load are designed to help users better understand their overall wellness and encourage small, consistent lifestyle changes that support long-term cardiovascular health.

The Galaxy Watch8 Series represents a significant leap forward in empowering users to better manage their well-being through intelligent and personalised health monitoring.

Driving Everyday Wellness

Samsung’s new Galaxy Watch8 Series also includes broader health and fitness capabilities. These include an Antioxidant Index[6] — introduced for the first time in a smartwatch — to measure carotenoid levels in the skin, and the Running Coach[7] to support fitness enthusiasts. There are also stress management tools, such as High Stress Alert, guided breathing exercises, and holistic energy scoring.

These wellness capabilities reflect Samsung’s broader commitment to transforming fragmented health data into meaningful, personalised insights, empowering consumers to take control of their health in simple, everyday ways. By combining advanced sensor technology, AI-driven insights, and a holistic health ecosystem, Samsung continues to set new standards for how wearables can improve lives — one night’s sleep at a time.

^[1]_{The study was conducted in December 2024 via online surveys, with 18,168 respondents (of which 3,098 were wearable users), aged 18 – 59 years old, in Australia, Indonesia, Malaysia, New Zealand, Singapore, Thailand, Philippines and Vietnam.}

^[2] _{National Sleep Foundation: How Much Sleep Do You Really Need?}

^[3]_{Based on three days of sleep analysis of user’s circadian rhythm and sleep pressure.}

^[4]_{The Sleep Apnea feature is an over-the-counter (OTC), software-only mobile medical application operating on compatible Galaxy Watch Series models and Galaxy smartphones. It is intended to detect signs of moderate to severe obstructive sleep apnea in the form of significant breathing disruptions in adult users age 22 and older over a two-night monitoring period. The feature is designed for on-demand use and is not intended for individuals previously diagnosed with sleep apnea. Users should not rely on this feature as a substitute for professional diagnosis or treatment by a qualified healthcare provider. The data provided by this device is also not intended to assist clinicians in diagnosing sleep disorders.}

^[5]_{Wearing a compatible Galaxy Watch is required when sleeping for at least three of the most recent 14 days.}

^[6]_{To measure, the user should place the center of their finger on the sensor at the back of the Watch and hold it for five seconds. While Antioxidant Index can be measured using any finger, the thumb is recommended for the most accurate result. Repeat measurement due to uneven skin texture may lead to different results.}

^[7]_{Prior to starting the coach programme, taking a running level test and receiving a level designation is required.}