Argireline vs. GHRP-6

Category

Cosmetic

Growth

CAS no.

616204-22-9

87616-84-0

Molecular weight

888.99 g/mol

873.02 g/mol

Half-life

0.4 h

Sequence

Argireline

Argireline is a synthetic hexapeptide whose sequence corresponds to the N-terminus of the SNAP-25 protein. In vitro it has been shown to competitively inhibit SNARE complex formation (necessary for vesicle fusion in neurotransmitter release). Topical application is intended — given very limited skin permeation — to attenuate cholinergic signalling at the neuromuscular endplate. The effect is orders of magnitude weaker than intramuscular botulinum toxin; the clinical translatability of the in-vitro observations to the skin microenvironment is contested.

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.

Highest evidence

Studies

3

4

of which in humans

2

2

Effects recorded

3

4

Open conflicts

1

1

Documented adverse events

1

2