Narrower indications

• Melasma — 2 graded rows from 2 compounds checked

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. Decapeptide-12

   human RCT Direct outcome Not approved for this condition

   Who was studied

   women with Fitzpatrick phototype IV and moderate recalcitrant melasma, n=5, 16 weeks

   A split-face, randomised, double-blind, vehicle-controlled pilot applied 0.01% decapeptide-12 twice daily and graded melasma appearance on a 10-point scale, reporting improvement on the treated side in all five participants. The diagnosis studied was melasma specifically, not post-inflammatory hyperpigmentation, and n=5 with an investigator grading scale rather than MASI or colorimetry is the whole human controlled record. The larger decapeptide-12 studies on file are open-label and combine the peptide with 20% glycolic acid and sunscreen, so they cannot attribute any pigment change to the peptide.

   Source PubMed 4 primary sources read for this row

2. Tetrapeptide-30

   human RCT Direct outcome Not approved for this condition

   Who was studied

   women with Fitzpatrick skin types V-VI in South Africa, 12 weeks; enrolled number not reported in the source abstract

   A double-blind, vehicle-controlled study of a PKEK (tetrapeptide-30) formulation used expert grading of standardised digital images and reported the peptide formulation superior to vehicle on overall appearance and evenness of skin tone at 12 weeks; the abstract does not state the randomisation method or the number enrolled. The population was general uneven facial pigmentation in deeply pigmented skin, not a melasma diagnosis. A separate Experimental Dermatology paper reports four vehicle-controlled human studies, but its measured pigment-spot fading comes from PKEK combined with sodium ascorbyl phosphate, so that reduction is not attributable to the peptide alone.

   Source DOI 2 primary sources read for this row

3. Nonapeptide-1

   in vitro Mechanistic only Not approved for this condition

   Who was studied

   cultured human epidermal melanocytes and HaCaT keratinocytes under UVA exposure; no living subjects

   Recorded, and not evidence for this condition

   Nonapeptide-1 acetate was applied to cultured human melanocytes as a comparator agent and reduced melanin content and tyrosinase activity in the dish. No study on file measured pigmentation in a living person: nothing here is skin lightening in a human, and the step from a cell assay to a visible change in melasma or post-inflammatory hyperpigmentation is an argument, not a result. The one human trial that includes nonapeptide-1 is a proprietary multi-ingredient melasma maintenance formulation with phenylethyl resorcinol, aminoethyl phosphinic acid, antioxidants and sunscreen, which attributes nothing to the peptide.

   Source DOI 3 primary sources read for this row

Checked, and nothing recorded

3 compounds were checked against hyperpigmentation and produced no gradeable row.

• GHK-Cu — checked, no row on file
• Oligopeptide-34 — checked, no row on file
• Pentapeptide-18 — 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.