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Research peptide head to head

Ipamorelin vs Sermorelin

Both peptides appear in growth-hormone preclinical literature, but they act at different receptors. Sermorelin is a GHRH analogue acting on the hypothalamic GHRH receptor pathway. Ipamorelin is a GHRP (growth hormone releasing peptide) acting at the ghrelin receptor. The two are pharmacologically complementary in research models, often combined in preclinical literature. Neither has a UK marketing authorisation as a medicine.

Ipamorelin Sermorelin
Class GHRP (ghrelin receptor agonist) GHRH analogue
Amino acids 5 29
Mechanism Acts at GHSR-1a (ghrelin receptor) Mimics endogenous GHRH at pituitary
Developer Novo Nordisk Salk Institute / Serono
Most-studied research direction Postoperative ileus (discontinued phase II) Childhood growth-hormone deficiency (Geref, discontinued)
Half-life Approx 2 hours 10 to 20 minutes
UK regulatory status No marketing authorisation; research use only No marketing authorisation; research use only
Pairing in research literature Often combined with GHRH analogues Often combined with GHRPs
Typical retail price (per equivalent vial) Mid-range Higher (longer synthesis)

Cross-reference: Ipamorelin encyclopedia · Sermorelin encyclopedia.

Reviewed by Oliver Mackman, editorial director · last reviewed 2026-05-18