Comparison
GHRP-6 vs. Matrixyl
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Growth
Cosmetic
CAS no.
87616-84-0
214047-00-4
Molecular weight
873.02 g/mol
802.06 g/mol
Half-life
0.4 h
no data
Sequence
His-D-Trp-Ala-Trp-D-Phe-Lys-NH2Palmitoyl-Lys-Thr-Thr-Lys-SerMechanism of action
GHRP-6
GHRP-6 is a high-affinity agonist of the growth-hormone secretagogue receptor 1a (GHSR-1a) — the same receptor later shown to bind the endogenous hormone ghrelin. The identification of GHRP-6 as a pharmacological anchor led to cloning of GHSR in 1996 and the discovery of ghrelin itself in 1999. GHRP-6 stimulates pituitary GH secretion via a pathway independent of GHRH and can be combined synergistically with GHRH. Via GHSR in the hypothalamus it additionally activates NPY/AgRP neurons, producing an orexigenic (appetite-stimulating) effect in animal models.
Matrixyl
KTTKS is a fragment of the procollagen I sequence and appears to be part of a feedback mechanism in fibroblasts: elevated concentrations signal intact collagen synthesis and downregulate new synthesis, while low concentrations stimulate it. In cell-culture studies, stimulation of collagen types I/III, elastin, fibronectin and glycosaminoglycans has been documented. The palmitoyl modification is intended to improve skin penetration; effect at the site of action (dermal fibroblasts) depends on permeation.
Evidence base
Highest evidence
Human trial
Human RCT
Studies
4
5
of which in humans
2
2
Effects recorded
4
3
Open conflicts
1
0
Documented adverse events
2
1