Which is more potent?
Hexarelin is generally the strongest per microgram in the class, with GHRP-2 close behind; both are stronger than ipamorelin on raw GH response. Neither has outcome trials for the marketed uses.
Summary
Both are potent ghrelin-receptor agonists with cortisol and prolactin spillover. The practical differences are GHRP-2's Japanese diagnostic approval and hexarelin's faster desensitization.
Key answers
What do they share in side effects?
Both raise ACTH, cortisol, and prolactin in comparative endocrine work, which is exactly the non-selectivity that makes ipamorelin the community's cleaner option. GHRP-2 also showed a roughly 36 percent appetite increase in one controlled study.
Why are hexarelin cycles shorter?
Hexarelin's GH response attenuates with continuous exposure, and the 16-week study community sources cite most found no body-composition change. That is why its cycles are described as 4 to 8 weeks with breaks rather than ongoing use.
Comparison matrix
| Dimension | GHRP-2 | Hexarelin |
|---|---|---|
| Overall evidence grade | C | D |
| Evidence label | Limited human evidence | Limited human evidence |
| Regulatory status | Varies by product and jurisdiction | Not FDA-approved for listed uses |
| Editorial confidence | Moderate confidence | Low confidence |
| Efficacy | 0/5 not mapped | 0/5 not mapped |
| Safety | 0/5 not mapped | 0/5 not mapped |
| Regulatory risk | 3/5 moderate | 3/5 moderate |
| Product quality risk | 3/5 moderate | 3/5 moderate |
| Primary claim categories | Growth hormone and secretagogues, Muscle growth and performance | Growth hormone and secretagogues, Muscle growth and performance |
Peptide summaries
References
- 1.
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.
- 2.
FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks 2026.
Accessed 2026-06-08.
FDA summarizes potential significant safety risks and missing safety information for several nominated peptide bulk substances.