15 sec
Non-invasive test. No blood, no labs, no wearable.
200,000
Individual measurements taken during a single 15-second reading.
Unlimited
Re-test as often as you like once you own the device.
Measure What Matters
Oxidative stress drives cellular dysfunction
Inflammation is everywhere in modern life, and antioxidants are the body's natural defense for healthy aging -- but modern food is short on the micronutrients your cells need for that protection. So the real question is simple: how do you know whether your cells are actually protected? You measure. PRYSM shows how your body responds to your diet, stress, and supplements over time -- so you can adjust with confidence instead of guessing.
How It Works
What the reading actually measures
These are the pigments that make carrots orange, tomatoes red, and leafy greens deep green -- and they are among the most important nutritional biomarkers in the body. They show up in nearly every cell, tissue, and organ, working as an antioxidant defense against the oxidative byproducts of everyday cellular metabolism. Your skin accumulates them in rough proportion to what you eat and absorb, building up over roughly two months. PRYSM reads that concentration directly through your skin, using resonance Raman spectroscopy to take about 200,000 individual measurements in about 15 seconds.
A higher score reflects stronger antioxidant support from the fruits and vegetables you are actually eating and absorbing -- one piece of how well your cells are able to maintain and defend themselves. The correlation between this skin measurement and actual fruit and vegetable intake has been validated against biopsy and blood analysis in published research.
- Non-invasive: your palm on the reader, no blood draw, no needles.
- Reads cellular antioxidant status in real time, right in front of you.
- Reflects roughly the last two months of diet and absorption, not just today.
- Re-test over time to see real dietary changes show up as a real number.
A measurement, not a diagnosis. PRYSM measures your antioxidant status through the skin -- a marker of nutrient status. It does not diagnose, treat, or cure any disease, and it is not a substitute for your doctor or standard blood work.
How Accurate It Is
About ±10%, and here is what that sits beside
Every page selling one of these calls it accurate. Almost none of them print a figure. Here is ours, next to the everyday measurements you already trust.
| Measurement | Typical margin |
|---|---|
| This measurement | about ±10% |
| DEXA body composition | ±2-4% |
| Heart-rate wearable | ±2-5% |
| A single blood draw | ±5-10% |
| Bioimpedance body fat | ±5-10% |
| Blood-pressure cuff | ±5-15% |
| Continuous glucose monitor | ±10-20% |
The rule that follows from the table is the part that matters: no trusted health number is read from a single reading. Nobody diagnoses anything from one blood-pressure cuff reading either. The trend is the measurement.
The Limits
What this measurement cannot tell you
Read this before you decide whether the number is worth anything to you. It is on the page you buy from on purpose.
It does not cover most of your nutrition
It says nothing about your vitamin C or vitamin E status, and nothing at all about vitamin D, B vitamins, magnesium, zinc, iron or omega-3s. It is one family of antioxidant micronutrients, not every antioxidant, vitamin and mineral you have.
It cannot separate one micronutrient from another
You get one number, not a breakdown. And because skin stores some of these micronutrients more readily than others, the ones most associated with eye health and cognition are under-represented in it. Dr. C-Y. Oliver Chen of the Tufts HNRCA Antioxidants Research Lab makes both points in the Tufts Health and Nutrition Letter, independently of us.
It does not diagnose anything
A high number is not a certificate of health, and a low number is not a diagnosis of anything. It is not a substitute for blood work or for your provider, and no reading here should change a medication or a treatment.
One reading on its own means very little
Normal variation is around ten percent, so two readings a week apart can differ without anything having changed in you. The trend across months is the measurement. A single number is the raw material.
The reading can be thrown off by your hand
Lotion, hand sanitizer, self-tanner and dirt all sit between your skin and the light. Clean, dry, product-free hands, and the same hand every time.
Some people should not bother
If you already eat a wide range of vegetables every day and you are not trying to verify whether something you take is being absorbed, a number will not change what you do next. We would rather say that than sell you a reading you do not need.
Re-Testing
How often to re-test, and how long a change takes to show
Every 8 to 12 weeks, and monthly is about as often as a change is real rather than noise. Owning the reader means you can test more than that. It just will not tell you more. Here is the reasoning, in three windows.
Days 1-14
Noise. Normal variation, and nothing you changed has had time to accumulate in skin yet. Do not read anything into it.
Weeks 3-6
A direction. If something is moving, this is where it starts to show above the ordinary variation.
Weeks 8-12
A real trend. This is the window where a sustained change is genuinely measurable.
Where those windows come from. A registered, randomized, double-blind, placebo-controlled 12-week trial (Hester and colleagues, 2026, NCT06749808) with 46 adults completing it -- 29 on a multivitamin, 17 on placebo. The readings did not separate from placebo until week 4 on one reader and week 8 on the newer one, and at 12 weeks the supplement group was up 42% on one and 41% on the other, with no change in the placebo group. That is a group average from one trial on one formulation, not a forecast for your reading.
The Bigger Picture
Why these nutrients are the clearest window into your cells
Here is what almost no one -- even in the research world -- realizes: these antioxidant nutrients are present in virtually every cell, tissue, and organ in your body. Skin, eyes, liver, adrenal glands, reproductive tissue -- these pigments from colorful plants sit inside your cell membranes, working as a frontline antioxidant defense, helping cells communicate through gap junctions, and buffering the oxidative stress of everyday metabolism. Because they are active across every major system, your level of them is one of the clearest single snapshots of how well your cells are protected -- and a marker that tracks with healthy aging and cellular function.
What Lab Tests Will This Improve?
Which measurements move, and how
Lab tests are not diseases. They are measurements of how your cells and organs are functioning. These nutrients do not treat any disease -- but they influence what these lab measurements show, through a specific mechanism. Here is which measurements each one moves, and how.
Carotenoids (mixed, from fruits & vegetables)
- Carotenoids (mixed, from fruits & vegetables) → Skin carotenoid score: Carotenoids accumulate in skin tissue roughly in proportion to fruit and vegetable intake and absorption over about the prior two months, so the score itself is a direct structural readout of dietary antioxidant intake.
- Carotenoids (mixed, from fruits & vegetables) → hs-CRP (inflammation): Diets rich in carotenoid-containing produce are associated with lower systemic inflammatory marker levels, plausibly by reducing the oxidative stress that feeds into inflammatory signaling.
- Carotenoids (mixed, from fruits & vegetables) → GGT (oxidative stress marker): GGT is part of the body's glutathione recycling system, so chronically elevated GGT partly reflects oxidative stress; supporting antioxidant defenses through carotenoid intake is mechanistically linked to lower oxidative burden.
- Carotenoids (mixed, from fruits & vegetables) → Oxidized LDL: Carotenoids are lipid-phase antioxidants that quench reactive oxygen species inside cell membranes and lipoprotein particles, reducing the oxidative modification of LDL that this marker reflects.
This is education about how nutrition influences function measurements -- it is not a diagnosis, and not a substitute for your provider or standard labs.
The Science
The research on carotenoid status
This is education about the science of carotenoids and antioxidant status -- not a claim that any measurement or product treats, cures, or prevents disease. The strongest, most honest version of this story is below, including where the evidence is mixed.
Featured Study
Exploring carotenoids: Metabolism, antioxidants, and impacts on human health
Bufka J, Vankova L, Sykora J, Krizkova V · Journal of Functional Foods (2024), open access
A 2024 open-access review showing carotenoids accumulate inside cell membranes and lipophilic compartments in virtually every tissue, act as antioxidants and cytoprotectants, and drive cell-to-cell communication through gap junctions -- placing carotenoid status at the center of how cells stay healthy. The review also states their potential negative effects honestly.
Read the studyA validated window into your cells
The skin carotenoid measurement is a validated biomarker of fruit-and-vegetable intake and carotenoid status -- it tracks real dietary change.
- Non-invasive Raman spectroscopic detection of carotenoids in human skin (the founding method) — Journal of Investigative Dermatology, 2000
- Concurrent validity of skin carotenoid status as a concentration biomarker of vegetable and fruit intake — Nutrition Journal, 2019
- Reflection spectroscopy-assessed skin carotenoids are sensitive to change in carotenoid intake (6-week RCT) — Journal of Nutrition, 2023
Antioxidant defense inside every cell
Carotenoids are a frontline antioxidant and photo-protectant against oxidative stress from inside and outside the body.
Higher status, healthier aging
In population research, higher carotenoid status is associated with lower all-cause mortality. This is an association in observational data, not proof of cause.
- Serum total carotenoids and all-cause mortality (Japanese cohort) — Cohort study, 2021
Cardiovascular & metabolic markers
Skin carotenoid score is associated with metabolic-syndrome and cardiovascular-risk markers in general populations -- again, associations, not diagnoses.
- Skin carotenoid scores and metabolic syndrome in a general Japanese population (Hisayama study) — International Journal of Obesity, 2024
- Association between atherosclerotic cardiovascular disease score and skin carotenoid levels — Scientific Reports, 2024
Brain, cognition & eyes
The carotenoids lutein and zeaxanthin concentrate in the brain and retina, where trials link them to cognitive and eye-health measures.
The honest part: food, not megadose pills
Higher carotenoid status from a colorful diet consistently tracks better health -- but that is NOT a reason to megadose isolated beta-carotene pills. Two large trials (ATBC in 1994 and CARET in 1996) found high-dose synthetic beta-carotene supplements increased lung cancer in smokers. That result is exactly why PRYSM measures your whole-food carotenoid status -- a marker of how you are actually eating and how well your cells are protected -- rather than pushing a single high-dose pill. Dose, source, and your starting point all decide the outcome.
- ATBC: alpha-tocopherol, beta-carotene and the incidence of lung cancer in male smokers — New England Journal of Medicine, 1994
- CARET: beta-carotene and retinol for lung cancer in smokers and asbestos-exposed workers — New England Journal of Medicine, 1996
What Shapes Your Score
Your score is not one thing -- it is the sum of what you eat, what you take, how much oxidative pressure your body is under, and how it distributes across your tissue.
Diet
Fruit and vegetable intake is the single biggest driver of your score.
Supplements
Antioxidant supplements raise the level held in skin over time.
Oxidative stress
Smoking, alcohol, chronic stress, and UV exposure burn through antioxidant reserves faster.
BMI & lifestyle
Body composition and activity level affect how these nutrients distribute across tissue.
Own it once, test as often as you like
PRYSM iO is a one-time purchase. There is no per-reading fee and no lab wait -- unlimited testing for you and your whole family, whenever you want a fresh read.
Want the full device walkthrough first? See the complete PRYSM iO page.