Peptide education
Tripeptide-10 citrulline
Tripeptide-10 citrulline is a synthetic cosmetic ingredient studied for skin suppleness. Despite its name, the cited paper describes it as a tetrapeptide.
A small blinded cream study reported increased suppleness from baseline in the peptide group, while the placebo group had no significant within-group increase. A separate randomized study found mixed differences in skin-surface measures across four formulations.
Overview
Quick answer
A change in an instrument's skin-suppleness reading is not the same as a measured reduction in wrinkle depth or proof of collagen repair.
Why does the name say tripeptide?
The ingredient name includes citrulline after tripeptide-10. The cited study describes the resulting substance as a tetrapeptide.
What did the cream study measure?
It used an instrument to assess skin suppleness after 28 days. The peptide group changed from baseline; the report did not clearly present a significance test of the difference between groups.
Do the studies prove wrinkles are removed?
No. One study measured skin suppleness; another measured skin-surface patterns and water loss. Neither establishes wrinkle removal across products.
Evidence
Evidence snapshot
Twenty-two received the test cream and 21 received placebo for 28 days.
Experiments examined changes in fibril formation and diameter distribution.
Creams contained the tripeptide, another peptide, both, or neither.
Claims
Common claims vs evidence
| Claim | Human evidence | Mechanistic evidence | Verdict |
|---|---|---|---|
| The ingredient repairs collagen and removes wrinkles. | The small cream studies measured suppleness, skin-surface patterns, and water loss, not wrinkle removal across products. | Laboratory and exploratory biopsy findings examined collagen fibril organization. | These findings do not establish wrinkle removal or collagen repair in every product user. |
Bottom line
Main takeaway
The full ingredient is a four-residue peptide despite the shorter-looking name.
The studies used particular creams and ingredient preparations, not every formula on the market.
Distinguish within-group change from a statistically tested between-group difference.
Identity
What it is
The sequence is described as Lys-Asp-Ile-citrulline.
The peptide was designed around a collagen-binding sequence associated with decorin.
Research
Research evidence
A single-blind, placebo-controlled study evaluated a liposomal cream in 43 women. A separate randomized study compared four creams in 24 women; another exploratory observation involved skin biopsies from three people.
| Study / evidence area | Population | Design | Product context | Main outcome | Limitations | Weight |
|---|---|---|---|---|---|---|
| Skin suppleness comparison | 43 women; the 22 in the peptide group were aged 40 to 58, and placebo-group ages were not stated in the primary report | Single-blind, parallel-group comparison over 28 days | Liposomal peptide cream in 22 participants and placebo cream in 21 | The test group had a reported increase from baseline in instrument-measured suppleness; no significant within-group increase was reported for placebo. | Small sample, short follow-up, manufacturer-affiliated authors, no stated identity of the blinded party, and no clearly reported between-group significance test. | Limited controlled product evidence |
| Four-arm cream comparison | 24 women aged 30 to 60 across four groups | Randomized, vehicle-controlled comparison over 60 days | Creams containing tripeptide-10 citrulline, acetyl hexapeptide-3, both peptides, or neither | Some between-group differences in skin-surface patterns and water loss varied by measure and time point; synergy was not established. | Small groups, short follow-up, and a commercial ingredient preparation limit generalization to other formulas. | Limited controlled formulation evidence |
Use context
Reported use context
The studies used different creams and application schedules, so their findings apply to the tested formulations.
Study and label context
Participants applied the assigned cream daily for 28 days.
The report described a cream containing 0.01% liposomed tetrapeptide; the preparation and concentration basis matter. This is not a recommendation.Participants applied their assigned cream twice daily for 60 days.
The tripeptide creams contained 5% of a commercial ingredient preparation, not necessarily 5% pure peptide. This is not a recommendation.Cautions
Safety and unknowns
- The studies' sizes and duration cannot exclude uncommon or delayed reactions.
- A different formula may have different tolerability because of its other ingredients and delivery system.
Product quality
Product identity and quality
The tested cream used a liposomal peptide preparation; other products may differ.
Complete ingredient name
The citrulline-containing ingredient is not just the three-residue portion.
Delivery system
A result from one liposomal cream may not apply to another formulation.
Concentration basis
A percentage of an ingredient preparation may differ from the amount of pure peptide.
Mechanism
How it is proposed to work
The ingredient was designed to imitate part of decorin's interaction with collagen. Laboratory findings are not proof of the same effect in living skin.
Investigators measured collagen fibril assembly and diameter in experimental models.
The small biopsy observations do not establish a controlled clinical mechanism.
Details
Technical details
Sources
References
- 1.
PubMed. A new decorin-like tetrapeptide for optimal organization of collagen fibres
doi:10.1111/j.1468-2494.2008.00429.x PMID:18377618
Laboratory and skin-model experiments plus a small single-blind, placebo-controlled cream comparison.
- 2.
Primary study. The efficacy study of the combination of tripeptide-10-citrulline and acetyl hexapeptide-3. A prospective, randomized controlled study
doi:10.1111/jocd.12314 PMID:28150423
Four-arm study comparing creams containing the peptides separately, together, or neither; the sample was small and results varied by measure and time point.
- 3.
Cosmetics. Topical Peptide Treatments with Effective Anti-Aging Results
doi:10.3390/cosmetics4020016
Review describes the Lys-Asp-Ile-citrulline sequence and summarizes the small cream study.
- 4.
FDA. Is It a Cosmetic, a Drug, or Both? (Or Is It Soap?)
US product classification depends on intended use.