Two very different products now share one name. The OS-01 peptide is the skincare ingredient OneSkin built its creams around: a lab-designed peptide meant to quiet worn-out "senescent" skin cells. But if you search for OS-01 today, you'll also find $195 bottles of 100 mg capsules, and the label on at least one of them describes a completely different chemical. This guide covers what OS-01 is, what the human studies actually measured, what OneSkin's products cost, and what those capsules really contain.
🔑 Key Takeaways
- Every published human study of OS-01 tested a cream, not a capsule
- One trial result in the headline doesn't survive a look at its own table
- The OS-01 capsules sold online list a chemical formula that isn't a peptide at all
- The cheapest way into the tested formula isn't the face cream
- All of the human evidence comes from the company that owns the patent
Prices were checked on oneskin.co and swisschems.is on November 5, 2026. Every study figure links to its source in the list at the end.
What Is the OS-01 Peptide?
It's a short peptide OneSkin found by screening. Its scientists tested hundreds of candidate peptides on skin cells from people with progeria, a rare disease of fast aging, and kept the ones that cut the share of senescent cells. Of 764 variants, "Peptide 14" did best, and it became OS-01 (Zonari 2023).
On OneSkin's ingredient lists it appears as Decapeptide-52, the cosmetic name, which tells you it is ten amino acids long. The papers we read don't print its amino acid sequence.
Senescent cells are cells that have stopped dividing but keep releasing inflammatory signals. OS-01 is described as senomorphic: in lab work it calmed those cells and their signals rather than killing them, which is what a senolytic such as FOXO4-DRI is meant to do. The proposed route is an enzyme complex called PP2A, involved in DNA repair.
What the Lab Work on OS-01 Found
The early results come from cells and donated skin. Here is what they showed, and what they can't show.
- Skin cells. OS-01 lowered senescence markers in fibroblasts aged by progeria, old age, UVB light and a DNA-damaging drug, without harming the cells at the doses used.
- Donated skin. Skin samples from three donors (35, 55 and 79 years old) kept in culture for five days had fewer senescence markers, a thicker outer layer, and a DNA methylation "age" 2.6 years lower on average (Zonari 2023).
- Getting in. The team's topical formula, with 0.01% OS-01, delivered up to 2% of the peptide into the dermis of donated skin.
- Safety screens. The peptide was mostly non-toxic to skin cells up to 100 μM, passed standard gene-damage tests, and caused no visible reactions in a 54-person patch test (Zonari 2022).
A 2.6-year drop in an epigenetic clock in a dish of skin is interesting. It isn't the same as looking younger, and nobody has shown it in living people's faces. For where this fits among other longevity ideas, see our guide to anti-aging peptides by mechanism.
OS-01 Peptide Benefits: What the Human Trials Measured
Three small skin trials make up the human evidence. All three used OneSkin products, and all three were run by the company's founders. Here is every study we found, including the oral ones that don't exist.
The face trial
The cleanest design is the 2024 split-face study. Women put the full OS-01 moisturizer on one side of the face and the identical cream minus the peptide on the other, for 12 weeks (Zonari 2024).
- Water loss through the skin, a measure of barrier strength, fell 14% on the OS-01 side and 1% on the plain side. The gap was statistically clear at week 6 and just missed at week 12 (p = 0.055).
- Skin texture improved 5% on the OS-01 side and not at all on the plain side.
- Wrinkle depth around the eyes improved 6.6% on the OS-01 side, but the difference from the plain side was not statistically significant.
- Expert graders saw fewer lines and smoother skin on both sides, so a good part of the visible change came from the moisturizer itself.
The body trial
This was the bigger, randomized one. Sixty women aged 60 to 90 used either OS-01 BODY or a store-bought moisturizer on their bodies twice a day for 12 weeks; 52 finished (Zonari 2025).
The abstract says OS-01 "significantly improved skin barrier function" compared with the control. The paper's own table is more modest. Both creams cut water loss by similar amounts, and the between-group differences were far from significant (p = 0.92 on the forearm, p = 0.61 on the upper arm). The clear win was hydration on the upper arm: up 38% with OS-01 versus 7% with the control (p = 0.022).
Two more findings get quoted a lot. Blood levels of the inflammatory signal IL-8 fell in the OS-01 group. And a blood test of "biological age" (GlycanAge) rose 0.72 years in the control group and barely moved with OS-01, which the authors themselves call a trend, not a proven effect. The peptide wasn't detectable in anyone's blood, so any whole-body effect would have to come through the skin, not from OS-01 circulating.
The eye cream study
This one had no comparison group. Twenty-two adults used OS-01 EYE for 12 weeks, and hydration, firmness and elasticity all rose from the start (Zonari 2025, eye). The eye cream also contains acetyl hexapeptide-8 (better known as Argireline), hyaluronic acid and plant extracts, so the study can't tell you how much came from OS-01.
The main limitation: every human OS-01 study is small (22 to 60 people), lasted 12 weeks or less, and was written by OneSkin's co-founders, who are named inventors on the patent. Nobody independent has published a replication yet.
OneSkin OS-01 Products and Prices
OneSkin sells OS-01 only as skincare. We checked its full product list and found no capsule, powder or drink. It calls its creams "topical supplements", but that's a marketing term; they are cosmetics.
OneSkin also sells an OS-01 Face Rich Cream ($170), Face SPF 30 ($56) and Lip Mask ($42). A subscription takes 15% off. We found no published trial of the hair serum, rich cream, sunscreen or lip products.
Per millilitre, the body lotion is the best value by a wide margin, and it's the product in the largest randomized trial. Nothing in the papers says the face formula is needed for the face; the body formula just wasn't tested there.
OS-01 vs GHK-Cu and Matrixyl
All three are skincare peptides with modest evidence. The difference is in what each is meant to do and who has tested it.
Matrixyl has the larger single trial, with 93 women on a split-face design (Robinson 2005). GHK-Cu has the longest track record, mostly summarized by its own discoverer (Pickart 2018). OS-01 has the newest idea, targeting aging cells, but the thinnest independent data. None has been tested head to head against another.
If you'd like to compare costs, our copper peptide serum guide prices eight GHK-Cu serums per mL, and our Matrixyl guide covers how to use it. If you're deciding between any peptide and a retinoid, read peptides vs retinol first: retinoids still have the deeper evidence for wrinkles.
OS-01 Capsules: Same Name, Different Molecule?
This is the part most OS-01 pages skip. Several online sellers now list "OS-01 100mg x 30 capsules", including SwissChems, whose product card appears on this page.
Read SwissChems' own product page closely. The description calls OS-01 "a short synthetic peptide". But the Properties tab lists the formula C15H9Cl2N3O2S, the synonyms O-304 and ATX-304, CAS number 1261289-04-6 and PubChem CID 50923806. We looked that ID up: PubChem CID 50923806 is O-304, a small chemical with a molecular weight of about 380 that activates the energy-sensing enzyme AMPK. (PubChem gives its formula as C16H11Cl2N3O2S, one carbon off from SwissChems' listing.) It contains no amino acids. At least one other seller's "OS-01 capsule" page also uses "o-304" in its web address.
So the capsule label and OneSkin's peptide don't match. Either the capsule contains O-304 sold under a borrowed name, or the page's chemical details are wrong. SwissChems' page doesn't settle which, and we couldn't confirm the contents ourselves.
If the capsule is O-304: that compound does have some human data, just not for skin. In a 28-day trial, 65 people with type 2 diabetes on metformin took 1,000 mg a day as a liquid suspension. Fasting blood sugar fell modestly compared with placebo in a subgroup analysis, blood pressure dropped, and the drug was well tolerated (Steneberg 2018). The other results, on aging hearts and exercise capacity, come from mice (Ericsson 2021). O-304 is an unapproved investigational drug, not a supplement.
If the capsule is the OneSkin peptide: there is no published evidence at all for swallowing it. OS-01 has only been tested on skin and in skin cells, at 0.01% in a cream. Nobody has shown it survives digestion or reaches the skin from the gut.
Either way, the skin results in the table above belong to OneSkin's creams, not to a capsule.
OS-01 Side Effects and Who Should Be Careful
The creams were mostly well tolerated, but not perfectly.
- In the body trial, all three dropouts from the OS-01 group left because of skin reactions: a persistent rash or pimples and dry patches.
- In the face trial, one woman had dryness and a rash on the cheek for 26 days that the authors judged likely due to the product.
- The eye study reported no adverse events.
Patch test a new OS-01 cream on your inner arm for a couple of days before using it on your face, and stop if a rash appears. There are no data in pregnancy or breastfeeding.
Capsules are a different risk. O-304's human safety data cover 28 days in people with diabetes, monitored in a trial. It lowers blood sugar and blood pressure, which matters if you take medicine for either.
What to ask your doctor before trying OS-01 capsules: Could an AMPK activator interact with my diabetes or blood pressure medicine? Is there any reason it could affect my kidneys, heart or blood sugar? Should I have bloodwork before and after? If you compete in a tested sport, ask your federation about AMPK activators too.
OS-01 Capsule Price and Where to Buy
Here is what the capsule costs. SwissChems lists OS-01 100 mg / 30 capsules at $195, marked down from $220, which is 3,000 mg per bottle. That works out to $6.50 per capsule, or 6.5 cents per milligram. The code jqrlsday takes 10% off, bringing it to $175.50, or $5.85 per capsule. PeptideDeck earns a commission if you buy through the SwissChems link on this page.
On testing, the product page says the item is third-party HPLC-tested at a US laboratory, with a certificate of analysis per batch, and that SwissChems will refund the order and the test cost if an independent HPLC test comes back negative. When we checked its public test-results page on November 5, we didn't find an OS-01 report listed. Ask for the batch certificate before you buy, and check whether it names O-304 or a peptide. The page also labels the product for laboratory use only.
If what you want is the version with published skin data, that's a OneSkin cream, not a capsule. If you're drawn to oral longevity peptides more broadly, our guide to oral peptides covers which ones survive being swallowed.
Frequently Asked Questions
Sources
- Zonari A, et al. Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models. npj Aging. 2023;9:10. PubMed 37217561
- Zonari A, et al. In vitro and in vivo toxicity assessment of the senotherapeutic Peptide 14. Toxicol Rep. 2022;9:1632-1638. PubMed 36518461
- Zonari A, et al. Double-blind, vehicle-controlled clinical investigation of peptide OS-01 for skin rejuvenation. J Cosmet Dermatol. 2024;23(6):2135-2144. PubMed 38400612
- Zonari A, et al. OS-01 peptide topical formulation improves skin barrier function and reduces systemic inflammation markers: a pilot 12-week clinical trial. J Cosmet Dermatol. 2025;24(4):e70169. PubMed 40193112
- Zonari A, et al. Clinical efficacy of OS-01 peptide formulation in reducing the signs of periorbital skin aging. Int J Cosmet Sci. 2025;47(3):455-465. PubMed 39788697
- Alencar-Silva T, et al. Senotherapeutic Peptide 14 suppresses Th1 and M1 human T cell and monocyte subsets in vitro. Cells. 2024;13(10):813. PubMed 38786036
- Steneberg P, et al. PAN-AMPK activator O304 improves glucose homeostasis and microvascular perfusion in mice and type 2 diabetes patients. JCI Insight. 2018;3(12):e99114. PubMed 29925691
- Ericsson M, et al. AMPK activator O304 improves metabolic and cardiac function, and exercise capacity in aged mice. Commun Biol. 2021;4:1306. PubMed 34795407
- PubChem. Compound summary for CID 50923806 (O-304). pubchem.ncbi.nlm.nih.gov
- Robinson LR, et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-160. PubMed 18492182
- Pickart L, Margolina A. Regenerative and protective actions of the GHK-Cu peptide in the light of the new gene data. Int J Mol Sci. 2018;19(7):1987. PubMed 29986520
- OneSkin product pages (OS-01 FACE, EYE, BODY, HAIR, Face Rich Cream, Face SPF 30, Lip Mask), prices in USD and ingredient lists, checked November 5, 2026.
- SwissChems product page "OS-01 100mg / 30caps" and Independent Test Results page, checked November 5, 2026.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. OneSkin's OS-01 products are cosmetics backed by small, company-run studies. OS-01 capsules are unapproved, have no published human data as a peptide, and one seller's label describes O-304, an investigational drug. Talk to your doctor before taking any unapproved compound, especially if you take medicine for blood sugar or blood pressure.