What the Research Says About Prysm iO

Yale School of Public Health: Examining the Method Underneath

The approach behind Prysm iO - using skin carotenoid levels as a stand-in for nutritional status - was refined over more than a decade of published research, much of it from Dr. Susan T. Mayne's group at the Yale School of Public Health and Yale Cancer Center, who worked with physicists at the University of Utah that built the original scanning instruments.

The Yale team adopted the non-invasive scan for a practical reason: they were unwilling to send graduate students out to draw blood from children for a study of inner-city kids' nutritional status. A scan removed that obstacle.

Their 2013 review in Archives of Biochemistry and Biophysics pulled together their own work (among it a 1,375-person adult survey and a 381-child study) with the wider literature, and stated:

“Skin carotenoid status as assessed by RRS is an attractive biomarker for use in human studies. It is highly reproducible [...] and with the development of portable scanners, feasible for use in field settings.”

- Mayne ST, Cartmel B, Scarmo S, Jahns L, Ermakov IV, Gellermann W. “Resonance Raman spectroscopic evaluation of skin carotenoids as a biomarker of carotenoid status for human studies.” Arch Biochem Biophys. 2013;539(2):163-70. PubMed

The review also explains why an objective reading adds something that asking people what they ate cannot:

“Without objective verification that behavior change has occurred, results of trials [...] are difficult to interpret.”

- Same source (PubMed), on why self-reported diet data alone cannot show that a behavior change program has taken hold.

The authors concluded that skin carotenoid status is an objective marker of fruit and vegetable intake, that it shifts measurably with supplementation and dietary change, and that it may reflect overall wellness more broadly. They were also candid that diet accounts for only part of the variation observed and that larger studies were needed. That measured, peer-reviewed groundwork is what later scanners, Prysm iO included, build on.

Set Against a Blood Test

Serum carotenoids can also be measured with a specialist blood test. It is not part of routine bloodwork and can mean waiting around three weeks for a specialist lab. Nu Skin ran a study with dermatologist Dr. Zoe Draelos that compared Prysm iO's 15-second skin reading with that blood test in 97 participants.

As with any measuring device, Prysm iO has a margin of error, which Nu Skin puts at roughly ±10% in everyday use. Treat a single reading as a snapshot; the trend across repeated scans is the more useful signal.

A Lifestyle Study Beyond the Lab

Nu Skin also reports a study at Shanghai Jiao Tong University in which 589 healthy adults were scanned with Prysm iO and their scores compared with self-reported diet, lifestyle, fitness, sleep and skin health. Higher scores went hand in hand with eating more fruit, vegetables, whole grains and freshwater fish, a balanced BMI, making time for sleep, regular exercise and limiting UV exposure, along with better self-reported skin smoothness, hydration and tone and fewer digestive or cold/flu symptoms. Lower scores went with more fried food, sugary drinks and red meat.

These are Nu Skin-reported correlations built on self-reported diet and outcomes, not an independently published, peer-reviewed paper. They are supporting information, not equivalent to the Yale biomarker research above.

Source: a Nu Skin research bulletin on correlations between skin carotenoid score and diet, lifestyle and skin attributes (NSE Products, 2026), principal investigator Professor Cai of Jiao Tong University. Read the bulletin (PDF). The bulletin also reports a correlation of 0.806 between Prysm iO and BioPhotonic Scanner S3 scores in the same 589 people.

Recognition From Beyond Nu Skin

Since launch, Prysm iO has also won recognition separate from Nu Skin's own research program:

• Achievement in Technology Innovation - TITAN Business Awards (winner page)
• Best of Category, Wellness Insight - Globee Business Awards
• Personal category winner - Good Design Awards 2025 (project page)

Prysm Certified Products and the Score Guarantee

Nu Skin labels certain products “Prysm Certified”, meaning its own scientists believe those products are formulated to help raise a client's Prysm Score over time. The company pairs this with a money-back guarantee: if a client's score has not improved after 90-100 days on a certified, Prysm-eligible product, the purchase is refundable, subject to Nu Skin's Terms and Conditions. As always, how you describe any product to a client should follow your professional body or regulator's rules and the permitted claims in your country.

Twenty Years of Development

Prysm iO is the fourth generation in a line of scanners that started in 1999 with Pharmanex's first Biophotonic Scanner. That machine filled a room and needed about an hour to calibrate, yet it was the first to measure antioxidants through the skin without a needle. A smaller, portable model followed in 2002, based on Raman spectroscopy (a technique that goes back roughly a century to physicist C.V. Raman). The S1 went on sale in 2003, the S2 in 2006, and the S3 in 2013 - Bluetooth-enabled, with 30-second scans, and eventually used in 51 countries for over 25 million scans.

Prysm iO is a new generation, not a relabelled S3. It scans a fingertip rather than the palm and relies on a different method: patent-pending “spectral ray” technology, which looks at how skin absorbs and reflects hundreds of thousands of light measurements per scan (the same basic principle as a pulse oximeter) instead of the emitted-signal approach of Raman spectroscopy. Its AI-driven scoring algorithm still references the Raman research base, but the 30-second scan time and the Raman method belong to the S3 generation rather than to Prysm iO. What carries over is the 20-plus years of R&D and the data from over 25 million scans behind the underlying science.