GHRP-6 vs Ipamorelin
| GHRP-6 Research Use Only | Ipamorelin Research Use Only | |
|---|---|---|
| Evidence rating |
2/5 Limited
Evidence rating 2 out of 5: Limited
|
2/5 Limited
Evidence rating 2 out of 5: Limited
|
| Regulatory status | Not approved. Superseded by more selective secretagogues; largely of historical and research interest. | Investigational only, and not approved anywhere. Two phase 2 trials in postoperative recovery of gastrointestinal function were completed without demonstrating benefit, after which development was abandoned. Widely supplied through wellness clinics and research-chemical sellers, which is not the same as being lawfully available. |
| Category | Growth Hormone Axis | Growth Hormone Axis |
| Drug class | First-generation growth hormone-releasing hexapeptide | Selective ghrelin receptor (GHS-R1a) agonist — pentapeptide |
| Route | Subcutaneous (research) | Subcutaneous (research) |
| Half-life | ~2.5 h elimination after IV in healthy men; the short figures quoted elsewhere are its ~8 min distribution phase. | ~2 hours |
| Sequence length | 6 residues | 5 residues |
| Molecular weight | 873 Da | 711.9 Da |
| Studied in | Extensive endocrine pharmacology research; small cardioprotection studies; no completed therapeutic development program. | Healthy-volunteer intravenous pharmacokinetics and GH response (1999); two completed phase 2 trials of postoperative recovery of gastrointestinal function, neither positive, after which development stopped; rodent studies of gut motility, longitudinal bone growth and bone mineral content. |
| Who should avoid it |
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| Legal status | Not approved for human use in any major market. | Not approved by the FDA, the EMA or any comparable regulator for any indication, and not eligible for lawful pharmacy compounding in the United States. Selling it for human use is unlawful. “Research use only” or “not for human consumption” labelling is a seller’s disclaimer about intended use, not a regulatory category, and confers nothing on the buyer. The compounding position is disputed and moving; the dated record is on this page. |
Benefits — GHRP-6
- Powerful appetite stimulation
Among the strongest orexigenic effects of any peptide — potentially useful in cachexia, and unwanted in almost every other context.
- Reliable GH release
Effective as a pituitary stimulus, historically important for characterising the GH axis.
- Preclinical cytoprotective signals
Animal work suggests cardioprotective and gastric-protective effects.
Benefits — Ipamorelin
- Selective GH release
Clean pharmacology: GH rises without the cortisol and prolactin spikes seen with hexarelin or GHRP-6.
- Minimal appetite stimulation
Unlike GHRP-6, it does not produce the intense hunger that makes those peptides impractical.
- Good short-term tolerability
Trial safety data in the ileus program were reassuring over short exposures.
- Synergy with GHRH analogs
The two mechanisms combine to produce a larger pulse than either alone.
- A measurable, reproducible GH pulse in healthy humans
A 1999 dose-escalation study in healthy male volunteers (eight men at each of five ascending intravenous infusion rates) found dose-proportional pharmacokinetics, a terminal half-life near two hours, and a single episode of GH release peaking around 40 minutes and decaying to negligible concentrations at every exposure tested. This is the clearest human evidence the compound does what it says — and it is evidence about a hormone measurement, not about anything a person would notice.
Risks & cons — GHRP-6
- Intense hunger
Often sabotages the body-composition goals people take it for.
- Cortisol and prolactin elevation
More pronounced than with newer secretagogues; chronic elevation carries real endocrine consequences.
- No approved use anywhere
Never completed clinical development.
- Rapid desensitisation
Response falls off with repeated dosing.
- Unregulated supply
Research-chemical market only.
Risks & cons — Ipamorelin
- No proven clinical benefit
The trials that were run targeted gut motility and were discontinued. Body-composition and recovery claims are untested.
- Unapproved and unregulated
Available only through compounding or grey-market suppliers, with corresponding quality uncertainty.
- Glucose and insulin effects
Raising the GH axis can worsen insulin sensitivity over time.
- Receptor desensitisation
Continuous ghrelin-receptor stimulation blunts the response; effects diminish with sustained use.
- Head/injection-site reactions
Headache, flushing and local reactions are reported.
A comparison is not a recommendation. Neither column is being suggested for you. Which — if either — is appropriate depends on your diagnosis, history and medications, and that is a conversation for a qualified clinician.