Comparison
GHRP-2 vs. Ipamorelin
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Growth
Growth
CAS no.
158861-67-7
170851-70-4
Molecular weight
817.93 g/mol
711.86 g/mol
Half-life
0.5 h
2 h
Sequence
D-Ala-D-2-Naphthyl-Ala-Ala-Trp-D-Phe-Lys-NH2Aib-His-D-2-Nal-D-Phe-Lys-NH2Mechanism of action
GHRP-2
GHRP-2 binds with high affinity to the GH secretagogue receptor (GHSR-1a) in the pituitary and hypothalamus. Activation leads to rapid release of pulsatile growth hormone. Unlike GHRH, GHRP-2 acts via a separate pathway and can be combined synergistically with GHRH to elicit maximal GH responses in provocation tests.
Ipamorelin
Ipamorelin is a selective agonist at the GH secretagogue receptor (GHSR-1a). Compared to GHRP-2 and GHRP-6 its selectivity for the growth-hormone axis is higher; ACTH, cortisol and prolactin are not significantly stimulated in clinical studies. This selectivity was the main reason for its development over older GHRPs.
Evidence base
Highest evidence
Human trial
Human RCT
Studies
4
4
of which in humans
4
3
Effects recorded
3
3
Open conflicts
0
1
Documented adverse events
1
1
Legal status
Full entries
Frequently asked questions
- What is the difference between GHRP-2 and Ipamorelin?
- GHRP-2 is classified as "Growth", while Ipamorelin is classified as "Growth". GHRP-2: Synthetic hexapeptide of the GH secretagogue family. Approved in Japan as GHRP Kaken as a diagnostic test for GH deficiency. Not available as a medicine outside Japan. Ipamorelin: Synthetic pentapeptide and selective growth-hormone secretagogue. Developed at Novo Nordisk in the 1990s as a pentapeptide GHRP successor; clinical development was discontinued after phase 2 (post-operative ileus). This page contrasts both neutrally and source-based — with no usage or dosing recommendation.
- Which peptide is better supported by science, GHRP-2 or Ipamorelin?
- The highest available evidence level is "Human trial" for GHRP-2 and "Human RCT" for Ipamorelin. A higher evidence level means more robust data, but says nothing about suitability for an individual. The full body of evidence is on each peptide's own page.
- What is the legal status of GHRP-2 and Ipamorelin in Germany and the United States?
- Germany: GHRP-2 — Unapproved, Ipamorelin — Unapproved. United States: GHRP-2 — Unapproved, Ipamorelin — Unapproved. These are factual summaries with source and review date on the individual pages.