The Science Behind Prysm iO

Yale School of Public Health: Validating the Underlying Science

The scanning method behind Prysm iO - reading skin carotenoid levels as a proxy for nutritional status - was developed and stress-tested over more than a decade of published research, much of it led by Dr. Susan T. Mayne's team at the Yale School of Public Health and Yale Cancer Center, working alongside physicists at the University of Utah who built the original scanning instruments.

Notably, the Yale team turned to this non-invasive scanning method specifically because their researchers were reluctant to send graduate students into the field to draw blood from children for a study on inner-city kids' nutritional status - a non-invasive scan solved a genuine practical problem, not just a marketing one.

Their 2013 review in Archives of Biochemistry and Biophysics - drawing together their own studies (including a 1,375-person adult survey and a 381-child study) alongside the wider published literature - concluded plainly:

“Skin carotenoid status as assessed by RRS is an attractive biomarker for use in human studies. It is highly reproducible and valid, 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 same review is explicit about why an objective reading matters more than asking someone what they ate:

“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 is not enough to confirm a behaviour change intervention actually worked.

Their conclusion was that skin carotenoid status is an objective biomarker of fruit and vegetable intake, tracks measurably with supplementation and dietary change, and may serve as a broader indicator of overall wellness - while also noting, honestly, that diet explains only part of the variation seen and that larger studies were still needed. That balanced, peer-reviewed foundation is what later scanning devices - including Prysm iO - build on.

An Early Stanford Medicine Study on Prysm iO Specifically

Separately, Nu Skin has an active research programme specifically on Prysm iO, including a pilot study with Stanford Medicine looking at biological ageing across 11 body systems.

This is early-stage pilot data (n=33). It has not yet completed peer review, and full results are expected to be published by the end of 2026. It is not a claim that Prysm iO diagnoses, treats, prevents, or reverses ageing or any medical condition.

Nu Skin has stated that six further independent studies are underway at universities around the world, including Stanford, to explore additional questions raised by this research - none of that further work is published yet.

Source note: Nu Skin's December 2025 launch announcement (Business Wire) names Stanford Medicine among its research partners. The specific figures in the box above come from Nu Skin briefing material, and the full study is expected to be published before the end of 2026.

Validated Against the Blood Test Gold Standard

A specialised blood test for serum carotenoids - not a routine part of standard bloodwork, and typically a 3-week wait at a specialist lab - is the accepted gold standard for measuring this biomarker. Nu Skin ran a clinical study, with dermatologist Dr. Zoe Draelos, correlating Prysm iO's 15-second skin reading against that blood test in 97 participants.

Like any measurement device, Prysm iO carries a margin of error - Nu Skin cites roughly ±10% in typical field use. A single reading should be treated as a snapshot; the trend across repeated scans over time is the more meaningful signal.

A Real-World Lifestyle Study

Nu Skin has also reported a study conducted at Shanghai Jiao Tong University, scanning 589 healthy adults with Prysm iO and comparing scores against self-reported diet, lifestyle, fitness, sleep, and skin health. Higher scores were associated with eating more fruit, vegetables, whole grains, and freshwater fish, a balanced BMI, prioritising sleep, regular exercise, and limiting UV exposure - alongside better self-reported skin smoothness, hydration, and tone, and fewer digestive or cold/flu symptoms. Lower scores were associated with more fried food, sugary drinks, and red meat.

This is Nu Skin-reported, correlational data based on self-reported diet and self-reported outcomes, not an independently published, peer-reviewed paper - useful supporting evidence, but not equivalent to the Yale biomarker research above.

Source: Nu Skin Clinical Bulletin, “Prysm iO Validation: 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.

Independent Recognition

Since launch, Prysm iO has also picked up recognition from outside Nu Skin's own research programme:

• 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 Certification and the Score Guarantee

Nu Skin certifies certain products as “Prysm Certified” - meaning their own scientists are confident those products are formulated to help raise a user's Prysm Score over time. Backing that up, Nu Skin offers a money-back guarantee: if a person's score hasn't improved after 90-100 days on a certified, Prysm-eligible product, it's refundable, subject to Nu Skin's Terms and Conditions. It's a concrete reason a person can trust the recommendation is backed by something more than a sales pitch.

Two Decades Behind the Device

Prysm iO is the fourth generation of a scanning lineage that began in 1999 with Pharmanex's first Biophotonic Scanner - room-sized, taking around an hour to calibrate, but the first device to measure antioxidants non-invasively through the skin. A smaller, portable version followed in 2002, using Raman spectroscopy (a technique dating back roughly a century to physicist C.V. Raman). The S1 launched commercially in 2003, the S2 in 2006, and the S3 in 2013 - Bluetooth-enabled, with 30-second scans, eventually reaching 51 countries and over 25 million scans worldwide.

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