Tripeptide-29 (INCI name), Gly-Pro-Hyp, glycyl-prolyl-hydroxyproline
Tripeptide-29 is Gly-Pro-Hyp, a three-amino-acid unit that repeats throughout collagen, made synthetically for creams and serums. The same tripeptide is a small part of oral collagen tripeptide supplements, which are mixtures of many collagen fragments.
None of these uses is approved. Uses tested in people come first, then claims that rest on animal studies or user reports.
Trial: tested in people, with the result. Animal: cell or animal studies only. No study: nothing published supports it.
Every compound’s uses, by body system: evidence map, and by condition: conditions A to Z.
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Gly-Pro-Hyp is a three-amino-acid unit that repeats throughout collagen. Swallowed in collagen supplements, it survives digestion and reaches the blood intact, and in mice pure Gly-Pro-Hyp reached the skin as its fragment Pro-Hyp. Given by mouth to UV-exposed mice, it raised skin collagen and hyaluronic acid and reduced collagen-breaking enzymes. How it might act when applied to skin hasn’t been studied.
AnimalMainly from cell and animal studies; not shown in people.
Whether topical tripeptide-29 reaches the dermis or changes collagen in people is unknown, and the oral trials can’t separate Gly-Pro-Hyp from the other fragments in the mixtures.
Kim 2018; Tak 2020
Not tripeptide-29 itself: oral collagen tripeptide mixtures rich in Gly-Pro-Hyp were tested at 1–3 g a day for 12 weeks; no topical strength has been studied.
Continuous, shown over 26 weeks
The ways Tripeptide-29 is most often run, each tagged with where it comes from.
Kim 2018, 64 women aged 40–60: skin hydration, wrinkling and some elasticity measures improved vs placebo. A mixture, not pure tripeptide-29.
Sold in serums under its INCI name; no study has tested any topical strength or schedule.
Applied to clean skin of the face, neck or hands. Topical only; never inject it.
Nothing special. Skip it and use the next application as usual.
Oral collagen tripeptide mixtures improved skin hydration and reduced water loss through skin vs placebo in 12-week trials of 64 and 84 women; no topical result exists.
TrialGiven by mouth to UV-exposed mice, pure Gly-Pro-Hyp raised skin collagen and hyaluronic acid and improved elasticity.
AnimalSkin irritation or redness
Patch-test first. Stop if it doesn’t settle.
No adverse effects reported in 12-week trials of oral collagen tripeptide mixtures
Those were mixtures taken by mouth, so they say little about creams.
Eye irritation
Keep it out of the eyes. Rinse with water if it gets in.
Stop and see a doctor for a spreading rash, swelling, blistering or hives, or eye pain after contact.
There are almost no human safety data for tripeptide-29, so most of these can’t be answered either way.
No data: no human safety data. A side effect that hasn’t been reported can still happen, especially with long or high-dose use. Any of these across every compound: the side-effect finder.
No product label covers tripeptide-29, so these come from human studies and from precautions based on how it works. Most important first.
Precaution: follows from how it works or from a related drug, and hasn’t been tested. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition. Every documented interaction, by medicine: drug interactions.
What’s known about pregnancy, breastfeeding, kidney and liver problems, age and surgery. Where nothing has been studied, the row says so.
Trial: from human studies. Precaution: not studied, so the caution follows from how it works or from a related drug. Ages are given as approved or studied; this site never gives doses for children. Across every compound: pregnancy, breastfeeding, kidney disease, liver disease, older adults and surgery.
Usually run on its own.
4 key published human studies, with how many people took part. Animal studies aren’t listed here.
Skin hydration was higher than placebo at 6 and 12 weeks, wrinkle measures improved at 12 weeks, and 2 of 3 elasticity measures beat placebo; no adverse symptoms. Not pure tripeptide-29.
Kim et al., Nutrients 2018, PMID 29949889
Water loss through the skin fell more than on placebo, and hydration improved more; 74 finished, with no notable side effects. Not pure tripeptide-29.
Tak et al., Front Med 2020, PMID 33521019
Hydration and elasticity changes were significantly better than with no supplement; adding vitamin C didn’t help.
Choi et al., J Cosmet Laser Ther 2014, PMID 24131075
Blood and urine levels of Gly-Pro-Hyp and Pro-Hyp rose with the amount of Gly-Pro-Hyp swallowed, showing it’s absorbed largely intact.
Yamamoto et al., Biol Pharm Bull 2016, PMID 26934933
No ongoing trial of tripeptide-29 is registered, and none has finished recently without publishing its results. Checked on ClinicalTrials.gov, October 7, 2026. Every compound: trials under way.
No published study has tested tripeptide-29 itself in people. The human trials used oral collagen tripeptide mixtures in which Gly-Pro-Hyp is a few percent (one stated 3%), enrolled 13–84 people for 12 weeks to 6 months, and several involved a supplement maker’s staff. Pure Gly-Pro-Hyp has cell and mouse data only, and skin penetration of the cosmetic form hasn’t been measured.
Tripeptide-29 is used on the skin, so the math is a dilution, not a syringe dose.
| Powder | Serum volume | Strength | Percent | ppm |
|---|---|---|---|---|
| 10 mg | 10 mL | 1 mg/mL | 0.1% | 1,000 ppm |
| 10 mg | 20 mL | 0.5 mg/mL | 0.05% | 500 ppm |
| 10 mg | 100 mL | 0.1 mg/mL | 0.01% | 100 ppm |
| 10 mg | 1,000 mL | 0.01 mg/mL | 0.001% | 10 ppm |
No published study has tested a topical strength, and no use level could be confirmed in two independent sources. The table shows only the arithmetic, from 10 ppm up to 1,000 ppm (0.1%).
Every compound side by side: the half-life chart and the storage chart.
Every compound’s numbers: the identifiers table.
Cosmetic tripeptide-29 is synthetic Gly-Pro-Hyp, sold as powder or solution. Oral “collagen tripeptide” products are hydrolysates of fish or animal collagen with many tripeptides; one trial product had 3% Gly-Pro-Hyp.
Tripeptide-29 is Gly-Pro-Hyp, a three-amino-acid unit that repeats throughout collagen, made synthetically for creams and serums. The same tripeptide is a small part of oral collagen tripeptide supplements, which are mixtures of many collagen fragments.
Gly-Pro-Hyp is a three-amino-acid unit that repeats throughout collagen. Swallowed in collagen supplements, it survives digestion and reaches the blood intact, and in mice pure Gly-Pro-Hyp reached the skin as its fragment Pro-Hyp. Given by mouth to UV-exposed mice, it raised skin collagen and hyaluronic acid and reduced collagen-breaking enzymes. How it might act when applied to skin hasn’t been studied. Whether topical tripeptide-29 reaches the dermis or changes collagen in people is unknown, and the oral trials can’t separate Gly-Pro-Hyp from the other fragments in the mixtures.
Not approved as a drug in the US or EU; used as a cosmetic ingredient, and related collagen tripeptide mixtures are sold as supplements. Cosmetics don’t need FDA approval before sale. Never nominated for FDA’s compounding bulk lists; it isn’t on any of FDA’s 503A or 503B category lists (May 2026 and March 2025 versions).
From human studies (Kim 2018; Tak 2020): Not tripeptide-29 itself: oral collagen tripeptide mixtures rich in Gly-Pro-Hyp were tested at 1–3 g a day for 12 weeks; no topical strength has been studied. These are the amounts sources reference, not recommendations.
No product label covers tripeptide-29, so these come from human studies and from precautions based on how it works. Anyone thinking of injecting it: It is a cosmetic ingredient, not made to injectable standards, and has never been tested by injection. People allergic to fish or other collagen sources: Applies to collagen tripeptide supplements made from fish or animal skin; synthetic tripeptide-29 contains no fish protein, but product labels don’t always say which is used. Pregnancy or breastfeeding: No human safety data exist for tripeptide-29.
Cool, dry and sealed; freezer for long-term storage of pure powder. After mixing: Finished serum: as labeled, cool and dark. This is common practice; no product label covers it.
No. Not named on the 2026 list. It’s a cosmetic ingredient and a fragment of dietary collagen, not a drug of the kind S0 covers. The 2027 list adds peptides to S0’s examples but names no cosmetic or food peptides.
Yes. The human studies section lists 4 published studies. Among them, from 2018: Skin hydration was higher than placebo at 6 and 12 weeks, wrinkle measures improved at 12 weeks, and 2 of 3 elasticity measures beat placebo; no adverse symptoms. Not pure tripeptide-29.
Trial Tripeptide-29 itself: none. A related oral collagen tripeptide mixture was taken at 16 g a day for 6 months in an open-label study.
Trial Sold for creams and serums, but skin penetration hasn’t been measured. Swallowed as part of collagen mixtures, Gly-Pro-Hyp is absorbed into the blood intact. Injection is untested.
Trial There’s no label and no overdose data for tripeptide-29. A related oral collagen tripeptide mixture at 16 g a day for 6 months caused no reported adverse events. Call Poison Help (1-800-222-1222), or emergency services for severe symptoms.
For how it works, who should avoid it and the limits of the evidence
For uses, the side-effect questions, special situations, trials, identifiers and status outside the US