What Has Been Published About Prysm iO

Yale School of Public Health: The Underlying Method

The approach behind Prysm iO, reading skin carotenoid levels as an indicator of carotenoid status, was developed over more than a decade of published research. Much of it came from Dr. Susan T. Mayne's group at the Yale School of Public Health and Yale Cancer Center, working with physicists at the University of Utah who built the original scanning instruments.

The Yale team turned to a non-invasive scan partly for a practical reason: they did not want to send graduate students into the field to draw blood from children for a study of inner-city kids' nutrition. A reading taken at the skin solved a real logistical problem.

Their 2013 review in Archives of Biochemistry and Biophysics, which brought together their own studies (including a 1,375-person adult survey and a 381-child study) and the wider literature, summarized the method this way:

“Skin carotenoid status as assessed by RRS is an attractive biomarker for use in human studies.”

- 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 same paper explains why an objective reading is useful: self-reported diet on its own makes it hard to tell whether a behavior change has actually happened.

The authors presented skin carotenoid status as an objective marker of fruit and vegetable intake that responds to supplementation and dietary change. They also noted that diet explains only part of the variation seen between people and that larger studies were needed. Prysm iO sits on top of that peer-reviewed foundation.

A Preliminary Stanford Medicine Pilot Involving Prysm iO

Nu Skin runs a research program on Prysm iO itself, including a small pilot with Stanford Medicine that looked at how Prysm Scores related to an epigenetic measure of biological age across 11 body systems. In that pilot the group with the highest scores averaged a lower biological-age estimate than the group with the lowest scores, by 4.3 years.

This is preliminary pilot data (n=33). It has not completed peer review, and full results are expected to be published by the end of 2026. It shows an association only. It is not a claim that Prysm iO diagnoses, treats, cures or prevents any disease or condition, or that it changes biological age.

Nu Skin has stated that six further independent studies are under way at universities around the world, including Stanford. None of that further work has been published yet.

Source note: Nu Skin's December 2025 launch announcement (Business Wire) names Stanford Medicine among its research partners. The specific figures above come from Nu Skin briefing material.

Comparison With a Serum Carotenoid Blood Test

Serum carotenoids can be measured with a specialized blood test. It is not part of routine bloodwork and results typically take around three weeks from a specialist lab. In a study involving 97 participants, with dermatologist Dr. Zoe Draelos, researchers compared Prysm iO's 15-second skin readings with that blood test.

As with any measuring device, readings vary. Nu Skin cites roughly plus or minus 10% in typical field use. Think of a single reading as a snapshot; the trend across repeated scans over time is the more useful signal.

A Lifestyle Study Outside the Lab

Nu Skin has also reported a study run 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 along with eating more fruit, vegetables, whole grains and freshwater fish, a balanced BMI, prioritizing sleep, regular exercise and limiting UV exposure, as well as better self-reported skin smoothness, hydration and tone. Lower scores went along with more fried food, sugary drinks and red meat.

This is Nu Skin-reported, correlational data built on self-reported diet and self-reported outcomes. It is not an independently published, peer-reviewed paper, so it is supporting evidence only and should not be weighed the same as the Yale biomarker research above.

Source: a Nu Skin research bulletin (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 Outside Nu Skin

Since its launch Prysm iO has also drawn recognition from organizations outside 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 a patient's Prysm Score improve over time. Alongside that, Nu Skin offers a money-back guarantee: if a patient'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.

Twenty Years of Development

Prysm iO is the fourth generation of a scanning lineage that started in 1999 with Pharmanex's first Biophotonic Scanner. That machine was room-sized and took about an hour to calibrate, yet it was the first to measure antioxidants through the skin without a needle. A smaller, portable version followed in 2002, using Raman spectroscopy, a technique that goes back roughly a century to the physicist C.V. Raman. The S1 launched commercially in 2003, the S2 in 2006 and the S3 in 2013, which added Bluetooth and 30-second scans and eventually reached 51 countries and more than 25 million scans worldwide.

Prysm iO is a new generation, not a repackaged S3. It scans a fingertip instead of the palm and uses a different underlying method: patent-pending “spectral ray” technology, which reads 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 that Raman spectroscopy relies on. 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, not to Prysm iO. What carries over is more than 20 years of R&D and the data from over 25 million scans behind the underlying science.