# Tripeptide-10 citrulline (Decorinyl)

Decorin-mimic peptide meant to tidy collagen fibres; one tiny randomised trial, no user reports.

- Page: https://peprank.xyz/peptides/tripeptide-10-citrulline
- Goals: Skin & hair (Supplement)
- Also known as: Decorinyl (Lipotec trade name, now Lubrizol); decorin-mimetic tetrapeptide (INCI calls it a tripeptide plus citrulline)
- Routes: Topical
- Safety tier: Strict: Caution · Balanced: Clean · Evidence only: Clean
- Risk axes (0 none to 3 severe): Seen harm 0, Mechanism 0, Data gap 2, Silent harm 0, Product 0
- Researcher estimate: 3/10 (no graded reports yet)
- Rank: #22 of 23 supplements
- Evidence: Human RCTs — one small randomised four-arm trial (24 volunteers in total, so about six per arm) found better skin microtopography than a peptide-free cream at day 20; the mechanism comes from the supplier's in-vitro collagen-fibrillogenesis assay. Too small to rely on
- Access: Supplement
- Onset: Weeks; the trial saw changes from day 20
- Lasts: Nothing persists after stopping
- Cost per month: ≈ €4–27 (researchers' estimate)
- Updated: 2026-10-30

## What users report

No first-hand Reddit reports name tripeptide-10 citrulline or Decorinyl as the active; searches for both names return unrelated products. It appears, if at all, deep in the ingredient lists of multi-peptide serums and creams, where no user outcome can be traced to it. The score is a placeholder for 'unknown', in line with how often users of anonymous multi-peptide serums report seeing nothing. Felt nothing: No first-hand reports found, so nothing can be counted.

**Effects:** claimed: smoother, suppler skin from more uniform collagen fibres (supplier in-vitro data); measured: less skin-surface roughness than a peptide-free cream at day 20 in a small trial

**Downsides:** no identifiable user outcomes; rarely disclosed at a known concentration

**Caveat:** The idea is collagen quality rather than quantity: aged skin has less working decorin, the protein that keeps collagen fibrils even, and this short peptide copies decorin's collagen-binding sequence. Whether it gets far enough into intact skin to meet dermal collagen is not shown. The one trial is tiny, and Lipotec's suppleness figures are unpublished. No harm signal; the open question is efficacy.

**Typical use:** Finished products at supplier-recommended levels (the trade product is a dilute solution), once or twice daily.

**Getting it:** Over-the-counter cosmetic: listed in some multi-peptide serums and creams; raw Decorinyl is sold to formulators.

**Stacked with:** Argireline (Tested together in the only trial; no synergy found.); Matrixyl (Usual neighbour in collagen-themed peptide serums.)

## Risk profile

- **Seen harm 0/3:** No serious adverse events in the one trial or anywhere in the literature, and no first-hand reports at all; exposure is real but small and untraceable inside multi-peptide products, so the zero is not strong reassurance.
- **Mechanism 0/3:** A decorin mimic that regulates how collagen fibrils assemble in vitro; decorin itself restrains growth-factor signalling rather than promoting it, and no pathway to serious harm is known.
- **Data gap 2/3:** One small randomised trial (24 volunteers across four arms, about a dozen exposed to the peptide, 60 days); no CIR assessment and no long-term data.
- **Silent harm 0/3:** The only plausible harms are irritation or contact allergy, noticed at once and gone on stopping.
- **Product 0/3:** Bought as finished over-the-counter serums and creams.
- **Never if:** known allergy to a product containing it; pregnancy and breastfeeding (no reproductive data, though systemic exposure from a cosmetic is expected to be negligible)

## Studies

- [Raikou et al., The efficacy study of the combination of tripeptide-10-citrulline and acetyl hexapeptide-3: a prospective, randomized controlled study (J Cosmet Dermatol 2017)](https://pubmed.ncbi.nlm.nih.gov/28150423/) (rct, n=24, 2017): Volunteers randomised to tripeptide-10 citrulline, argireline, both, or neither for 60 days: several between-group differences in skin roughness (cR2, cR3) and water loss reached significance, including tripeptide-10 citrulline versus no peptide at day 20. The authors call it clinical evidence of anti-wrinkle efficacy; no synergy between the two peptides was shown.
- [Puig et al., A new decorin-like tetrapeptide for optimal organization of collagen fibres (Int J Cosmet Sci 2008)](https://pubmed.ncbi.nlm.nih.gov/18377618/) (in-vitro, 2008): Lipotec screened tetrapeptides mimicking decorin's collagen-binding sites; tripeptide-10 citrulline regulated collagen fibrillogenesis in vitro, giving thinner, more uniform fibres. Supplier study.

## Sources

- [Raikou et al., J Cosmet Dermatol 2017 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/28150423/)
- [Puig et al., Int J Cosmet Sci 2008 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/18377618/)