Comparison
Two ghrelin-receptor secretagogues with the same goal and meaningfully different selectivity.
Both raise growth hormone in human challenge studies; ipamorelin is preferred in clinic and community discussion because comparative work found it did not raise ACTH or cortisol where GHRP-2 did.
GHRP-2 is generally described as the stronger secretagogue per microgram in endocrine literature, and ipamorelin as the more selective one. In practice both appear in similar community schedules of about 100 to 300 mcg per injection.
In comparative endocrine work, GHRP-2 (like GHRP-6 and hexarelin) also raised ACTH and cortisol, while ipamorelin did not at comparable GH responses. Ipamorelin also stimulates appetite less than GHRP-2 or GHRP-6, which is why it is positioned as the cleaner option.
Both are unapproved for the marketed uses, both are WADA-prohibited, and ipamorelin specifically failed a 2024 FDA Pharmacy Compounding Advisory Committee vote for 503A bulk use. Neither has controlled human outcome trials for physique or anti-aging claims.
| Dimension | Ipamorelin | GHRP-2 |
|---|---|---|
| Overall evidence grade | D | C |
| Evidence label | Limited human evidence | Limited human evidence |
| Regulatory status | Investigational / not approved | Varies by product and jurisdiction |
| Editorial confidence | Moderate confidence | Moderate confidence |
| Efficacy | 1/5 limited | 0/5 not mapped |
| Safety | 1/5 limited | 0/5 not mapped |
| Regulatory risk | 5/5 very high | 3/5 moderate |
| Product quality risk | 4/5 high | 3/5 moderate |
| Primary claim categories | Investigational GH secretagogue context, Healthy-volunteer PK/PD, Postoperative-ileus registry context, FDA compounding-policy review, Product-quality and regulatory risks | Growth hormone and secretagogues, Muscle growth and performance |
Ipamorelin is an investigational GH secretagogue with compounding-policy concerns. The current evidence is limited to healthy-volunteer PK/PD, postoperative-ileus registry context, and FDA 503A review rather than approved GHD, anti-aging, body-composition, recovery, or stack claims.
Real human endocrine data and a Japanese diagnostic approval; performance and physique claims remain unproven.
PubMed. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers 1999.
doi:10.1023/A:1018955126402 PMID:10496658 Accessed 2026-06-09.
Healthy-volunteer dose-escalation PK/PD study showing dose-proportional exposure and a transient growth-hormone response; useful for narrow human pharmacology context, not patient-outcome or wellness claims.
FDA. October 29, 2024 Pharmacy Compounding Advisory Committee (PCAC) Meeting 2024.
Accessed 2026-06-09.
FDA meeting summary reporting PCAC votes against placing ipamorelin free base or ipamorelin acetate on the 503A Bulks List because the available information did not support safety and efficacy in the reviewed contexts.
USADA. David Branch Receives Sanction for Violation of UFC Anti-Doping Policy 2019.
Accessed 2026-06-09.
Official USADA source stating that ipamorelin is a prohibited peptide-hormone / growth-factor substance under anti-doping rules that adopt the WADA Prohibited List.
WADA. The 2026 Prohibited List 2026.
Accessed 2026-06-08.
WADA states that S0 non-approved substances are prohibited at all times when they have no current approval by a governmental regulatory health authority for human therapeutic use.