Decapeptide-12

1 Identity

Cosmetic bulk peptide active — linear all-L decapeptide. and sometimes written Decapeptide-12 HCl or as the acetate. Not to be confused with Nonapeptide-1, which is sold into the same market segment and is a different molecule, nor with the unspecified vendor designation 'Lipopeptide', which names a structural class and not a substance.

Sequence

H-Tyr-Arg-Ser-Arg-Lys-Tyr-Ser-Ser-Trp-Tyr-OH (YRSRKYSSWY) is the sequence published for the phage-display-derived decapeptide marketed under this INCI name (Abu Ubeid and colleagues, Journal of Investigative Dermatology, 2009; no identifier is asserted for it). Ten residues, all L and all proteinogenic; free N-terminal alpha-amino group; free C-terminal carboxyl; no disulfide, no acylation, no amidation. Strongly basic — two Arg guanidino groups plus a Lys epsilon-amine plus the N-terminus, four basic centers against no acidic side chain at all — so the article binds counterion heavily and is always supplied as a salt. Three Tyr and one Trp give a genuine 280 nm chromophore, which is unusual in this catalog and is analytically useful: the comparison of the 214 nm and 280 nm traces is a specification requirement on this article rather than an optional check, because those four aromatic residues make this one of the few peptides in the catalog whose 280 nm trace carries real information. IMPORTANT: no sequence is asserted for this cosmetic-peptide group, so this string is a literature attribution and not a verification.

Molecular formula

C65H90N18O17 (free peptide, salt-free) if the sequence above is correct. The shipped article is a salt of four basic centers and its weighed formula will carry the counterion; no formula is complete for a lot until the counterion is declared and quantified.

Average mass

1395.544 Da for the free peptide C65H90N18O17, taken from the residue composition rather than quoted from a listing. Stated conditionally on the sequence attribution above. Note the salt burden: as the tetra-trifluoroacetate the weighed mass rises to roughly 1851 Da, meaning about 25 percent of the powder is counterion, so a lot weighed as the salt and specified against the free peptide is a quarter short of the stated substance. Net peptide content is not a refinement on this article, it is the label claim.

Monoisotopic mass

1394.67313 Da neutral for the free peptide. Working ions: [M+H]+ m/z 1395.68041, [M+2H]2+ m/z 698.34384, [M+3H]3+ m/z 465.89832. The 2+ and 3+ species dominate in positive-mode ESI on a peptide with four basic centers, and a method looking only for the singly protonated ion will report a weak or absent peak on a correct lot. A plus or minus 5 ppm window on the neutral is plus or minus 0.0070 Da.

Salt / variant note

(1) Nonapeptide-1, sold into the same segment by the same catalogs, different sequence and different mass — the two are routinely shelved together and the mass separates them at once. (2) 'Lipopeptide', a vendor designation naming a structural class rather than a molecule; a 200 mg vial of 'Lipopeptide' with no specified sequence is an unspecified substance. (3) Salt forms: acetate, hydrochloride and trifluoroacetate all circulate under the same INCI name, and on a four-base peptide the counterion is roughly a quarter of the weighed mass — the tetra-TFA and tetra-acetate forms differ from each other by about 220 Da at the same net peptide content. (4) Truncation and deletion sequences from solid-phase synthesis: loss of a single Ser gives -87.03 Da, loss of a Tyr gives -163.06 Da, and des-Trp at -186.08 Da is the one that also removes part of the 280 nm signal. (5) Oxidized Trp, +15.995 Da, which is the expected storage-related species on this peptide.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Evidence grade F for the whole cosmetic-peptide group: no compound-specific primary evidence, in vitro, animal or human, has been located for any member. Literature that does exist and its study type: in-vitro enzymology on isolated tyrosinase from the phage-display selection work (Abu Ubeid and colleagues, Journal of Investigative Dermatology, 2009; no identifier is asserted for it). Class-level literature: Imhof and Leuthard 2021, PMID 32882685 — systematic review of over-the-counter topical antiaging agents, which states the position for the class; Kraeling 2015, PMID 24754410 — in-vitro human cadaver and hairless guinea pig skin penetration, run on acetyl hexapeptide-8 and not on this article; Choi 2014, PMID 25143811 — in-vitro hairless mouse skin, run on the collagen pentapeptide pair. No ClinicalTrials.gov registration under this INCI name was identified. No marketing authorization in any jurisdiction.

4 Storage & specification

Storage

Lyophilized powder, -20 degrees C plus or minus 5 degrees C, desiccated with in-pack desiccant, protected from light; 2 to 8 degrees C acceptable for transit and for working stock held no longer than 30 days. The tryptophan residue is the oxidation-sensitive feature and drives the light-protection and headspace requirements; the three tyrosines are secondary. Sealed vials are equilibrated to room temperature before opening, because on a heavily salted basic peptide condensation on the cold solid moves the water figure, and the water figure moves the net peptide claim.

Shelf life

Provisional 24 months at -20 degrees C plus or minus 5 degrees C, assigned by protocol and not measured, pending long-term and accelerated data on the first three lots on a 0/3/6/9/12/18/24-month schedule. The tracked attributes are Trp oxidation (+15.995 Da), water content and counterion — not gross HPLC purity, which moves last. No Asp, no Asn, no Met and no disulfide, so deamidation, methionine oxidation and disulfide scrambling are not pathways here. The label is shortened on data and is never extended without a completed 24-month dataset.