Comparison
GHRP-6 vs. Lixisenatide
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Growth
Metabolic
CAS no.
87616-84-0
320367-13-3
Molecular weight
873.02 g/mol
4858.5 g/mol
Half-life
0.4 h
3 h
Sequence
His-D-Trp-Ala-Trp-D-Phe-Lys-NH2HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPSKKKKKK-NH2Mechanism 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.
Lixisenatide
Lixisenatide is a 44-amino-acid peptide based on exendin-4 (see exenatide) with six additional lysine residues at the C-terminus. This modification increases stability against DPP-4 degradation. The short half-life (~3 hours) and plasma peak around mealtime explain the predominantly prandial effect — stronger postprandial glucose action, weaker fasting glucose effect than weekly GLP-1 RAs.
Evidence base
Highest evidence
Human trial
Human RCT
Studies
4
5
of which in humans
2
5
Effects recorded
4
3
Open conflicts
1
1
Documented adverse events
2
1