Tripeptide-29 appears on ingredient lists of serums, creams and drinks sold on collagen claims, often next to hydrolysed collagen. Unlike most of the peptides covered on this site, it is not a lab-designed signalling sequence with a trade name. It is a piece of collagen itself, and it is small. This file checks what it is, what has been studied, and by which route. It is an ingredient file, not a product recommendation.
The molecule, and a naming trap
Tripeptide-29 is glycyl-prolyl-hydroxyproline, written Gly-Pro-Hyp or GPH. PubChem's record for it, CID 11778669, gives the formula C12H19N3O5, a weight of 285.30 g/mol and CAS number 2239-67-0, and lists "Tripeptide-29" and "CollagenTripeptide" as synonyms.
Gly-Pro-Hyp is the most frequent three-amino-acid unit in collagen's triple helix, which is why supplement makers call it collagen's building block. The hydroxyproline in collagen is 4-hydroxyproline. That detail matters for anyone checking the chemistry: a PubChem search for the plain name "Gly-Pro-Hyp" returns a different record, CID 21252274, built on 3-hydroxyproline, with the same formula and weight. The INCI name points to the collagen form; the shorthand name, in PubChem at least, does not.
How much has been studied, and under which name
On 2 October 2026:
| PubMed search | Records |
|---|---|
| "tripeptide-29" (the label name) | 0 — PubMed reports the phrase as not found |
| "collagen tripeptide" | 39 |
| with a skin, wrinkle or dermal term | 23 |
| tagged as randomized controlled trials | 6 |
| tagged as retracted | 0 |
| with a topical, cream, serum or cosmetic term (incl. Gly-Pro-Hyp) | 12 |
The INCI name used on labels has no research footprint at all. Everything published is under "collagen tripeptide" or the chemical shorthand, and much of it comes from supplement research.
The six randomized trials, by route
Read one by one, five of the six gave collagen tripeptide by mouth:
- Lin et al., 2026 (J Cosmet Dermatol, PMID 41918155; NCT06771388): 75 adults, 8 weeks, a 50 mL daily drink, liposomal against non-liposomal against placebo. Both collagen-tripeptide drinks improved dermal collagen density, hydration and elasticity against placebo; only the liposomal one reduced wrinkle area. Several authors work for TCI Co., the drink's developer, which also holds the copyright notice on the paper.
- Kim et al., 2018 (Nutrients, PMID 29949889): a low-molecular-weight collagen peptide, 1,000 mg daily for 12 weeks against placebo; hydration and elasticity improved.
- Choi et al., 2014 (J Cosmet Laser Ther, PMID 24131075): 32 volunteers, collagen peptide 3 g daily with or without vitamin C, or neither, for 12 weeks; the control group took no supplement rather than a placebo.
- Choi et al., 2014 (Clin Exp Dermatol, PMID 25283252): 3 g a day for 4 weeks after laser resurfacing.
- Hakuta et al., 2017 (J Dermatol Sci, PMID 29017796): atopic dermatitis, 3.9 g daily for 12 weeks against ordinary collagen peptides; 13 patients completed.
The sixth is the only topical one:
- Berardesca et al., 2009 (Int J Cosmet Sci, PMID 19496838): 40 women with sensitive, atopic-prone skin, 4 weeks, a product containing gluco-oligosaccharide and "collagen tripeptide F" against placebo. Roughness, water loss and redness improved more on the active product. Because it contained two actives, the trial cannot say what the tripeptide contributed, and sensitive-skin symptoms are not wrinkles.
The oral studies belong with the wider evidence on collagen supplements for skin and hair, which this site covers separately. What they show about a drink cannot be carried over to a cream.
The size argument, both ways
Most peptide ingredients sold for collagen claims are either large or carry a fatty-acid tail to help them into the skin's oily outer layer: palmitoyl tripeptide-5 weighs 612 daltons and palmitoyl pentapeptide-4 (Matrixyl) more again. Tripeptide-29, at 285 daltons, sits under the rough 500-dalton rule of thumb for what can cross intact skin. That is a genuine point in its favour on paper; a whole collagen chain, by contrast, is about 139,000 daltons (the collagen comparison).
It is also water-loving and carries no lipid tail, which works against passage through a fatty barrier, and the 500-dalton line is a guide, not a guarantee. No human study we found measured how much tripeptide-29 applied in a cream or serum reaches living skin, or what it does there. Its smallness is a reason the question is worth asking, not an answer to it.
On labels
INCIDecoder's ingredient page for tripeptide-29 showed 50 products on its first page on 2 October 2026, mostly Korean serums, creams and ampoules, often alongside hydrolysed collagen and other peptides. As with every peptide on a crowded list, its position and the absence of a stated amount usually leave its concentration unknown. Our guide to what peptides do for skin sets out how to read those lists.
What this file supports saying
- Tripeptide-29 is Gly-Pro-Hyp, collagen's commonest repeating unit, at 285 daltons.
- Its research record sits under "collagen tripeptide", and almost all of the controlled human work tested it as a drink or supplement.
- One topical randomized trial exists, of a two-active mixture for sensitive skin.
- Its small size makes skin penetration plausible; nobody has published a measurement of it.
Sources
- PubChem, CID 11778669 (glycyl-prolyl-hydroxyproline; synonyms incl. Tripeptide-29) and CID 21252274 (the 3-hydroxyproline isomer returned for "Gly-Pro-Hyp"), read 2026-10-02.
- PubMed E-utilities searches as tabled, run 2026-10-02, including the
quotedphrasesnotfoundcheck and theRetracted Publication[pt]filter. - Lin YK et al. 2026 (PMID 41918155); Kim DU et al. 2018 (PMID 29949889); Choi SY et al. 2014 (PMID 24131075; PMID 25283252); Hakuta A et al. 2017 (PMID 29017796); Berardesca E et al. 2009 (PMID 19496838) — abstracts read 2026-10-02.
- INCIDecoder, ingredient page "Tripeptide-29", read 2026-10-02.