Recorded under Skin ageing, alongside 2 other indications.

Compounds with a graded row

Ordered by rung, strongest first. The rung rates the study design; the chip beside it says what the study measured. Both are needed.

1. Hexapeptide-9

   human RCT Direct outcome Not approved for this condition

   Who was studied

   adult men and women with ageing skin, n not reported in the abstract; topical 0.002% serum twice daily, 56 days

   A randomised, double-blind, vehicle- and active-controlled 56-day trial of a topical 0.002% cyclized hexapeptide-9 serum measured crow's feet and forehead wrinkle number, area and roughness against a 0.002% retinol serum and vehicle, and reported larger reductions than retinol on all measured wrinkle outcomes except crow's feet roughness. The tested material is a cyclized variant, not plain hexapeptide-9, and the enrolled number was not reported in the abstract.

   Source DOI 1 primary source read for this row

2. Palmitoyl Pentapeptide-4 (Matrixyl)

   human RCT Direct outcome Not approved for this condition

   Who was studied

   Caucasian women aged 35-55, n=93, topical (3 ppm pal-KTTKS in a moisturiser), 12 weeks, split-face left-right randomised

   A 12-week double-blind, split-face, randomised comparison of a moisturiser with and without 3 ppm palmitoyl pentapeptide-4 measured facial wrinkles and fine lines directly, by quantitative image analysis and expert grading, and reported improvement versus the placebo side. It is a single cosmetic-industry trial in one narrow population; no independent replication is on file, and the peptide has no regulatory approval for any skin condition.

   Source DOI 1 primary source read for this row

3. Argireline (Acetyl Hexapeptide-3)

   human observational Direct outcome Not approved for this condition

   Who was studied

   adult women, n=19, topical hyaluronic acid serum with and without Argireline applied to opposite sides of the face, 4 weeks

   A double-blind, within-subject split-face study measured facial wrinkle scores by Visia imaging after 4 weeks and found no statistically significant wrinkle reduction on the Argireline side. Randomisation of side allocation was not reported, so this is graded below human_rct despite the vehicle control. It is the only controlled human wrinkle study of Argireline alone on file; every other human study of it is a multi-ingredient formulation from which the peptide's own contribution cannot be separated.

   Source PubMed 1 primary source read for this row

Checked, and nothing recorded

5 compounds were checked against facial wrinkles and produced no gradeable row.

• Dipeptide Diaminobutyroyl Benzylamide Diacetate — checked, no row on file
• Palmitoyl Tripeptide-1 — checked, no row on file
• Pentapeptide-18 — checked, no row on file
• Tetrapeptide-21 — checked, no row on file
• Tripeptide-10 Citrulline — checked, no row on file

A compound is here because someone looked and the sources did not support a row — not because nobody looked. Under the rubric, uncertainty resolves to no row, and a row resting on a vendor page or a clinic blog is worse than no row at all.