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Research peptide — not a dietary supplement
Ipamorelin is a research compound, not a regulated dietary supplement. It is typically administered by injection and sold “for research use only.” The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Ipamorelin studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 1998–2024 with a typical study size of 114 participants.
Based on 12 studies · 2 RCTs · 154 total participants
Confidence
LowBy outcome
The current evidence for Ipamorelin is insufficient to assign an evidence score, based on 12 indexed studies. A selective synthetic pentapeptide growth-hormone secretagogue (ghrelin/GHS-R1a agonist) sold for research use only. Honest appraisal: the evidence is mostly animal pharmacology showing it triggers a clean GH pulse; an early human PK/PD study confirmed it does release GH in people, but only as a short biomarker pulse — no human efficacy data exist. Its one real clinical-outcome story — a phase-2 trial as a postoperative-ileus drug — FAILED its endpoint (no significant difference vs placebo), and that clinical development stalled. It is not an approved medicine, not a regulated dietary supplement, and is banned in sport. Representative study: PMID 25331030.
The commonly studied dose of Ipamorelin is No validated human dose for any physique or anti-aging use. The published human studies were intravenous and hospital-based: an early dose-escalation PK/PD study (4.21-140.45 nmol/kg IV) confirmed a GH pulse, and the phase-2 ileus trial used 0.03 mg/kg IV twice daily. Grey-market subcutaneous use is unstandardized and not endorsed.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Semaglutide
Mostly mechanism / observationalAn FDA-approved GLP-1 receptor agonist (Ozempic/Rybelsus for type 2 diabetes, Wegovy for chronic weight management) with genuinely strong, large-RCT evidence for glycemic control and substantial weight loss, plus a cardiovascular-outcomes benefit. Honest appraisal: this is a real prescription medicine with real efficacy AND real risks — a boxed warning for thyroid C-cell tumors, pancreatitis and gallbladder risk, very common GI side effects, and growing concern about grey-market/compounded versions. It is included here for reference only, not as a supplement and not auto-recommended.
Last reviewed June 2026 · evidence from 12 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Ipamorelin
A selective synthetic pentapeptide growth-hormone secretagogue (ghrelin/GHS-R1a agonist) sold for research use only. Honest appraisal: the evidence is mostly animal pharmacology showing it triggers a clean GH pulse; an early human PK/PD study confirmed it does release GH in people, but only as a short biomarker pulse — no human efficacy data exist. Its one real clinical-outcome story — a phase-2 trial as a postoperative-ileus drug — FAILED its endpoint (no significant difference vs placebo), and that clinical development stalled. It is not an approved medicine, not a regulated dietary supplement, and is banned in sport.
Evidence is almost entirely preclinical animal pharmacology plus a human PK study confirming a GH pulse; the single human efficacy trial (postoperative ileus) failed its endpoint and no controlled data support any consumer benefit.
Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) developed in the late 1990s by Novo Nordisk as the first 'selective' growth-hormone secretagogue — meaning it stimulates a pulse of growth hormone (GH) by activating the ghrelin/growth-hormone-secretagogue receptor (GHS-R1a) on pituitary somatotrophs without the cortisol and prolactin spikes seen with earlier GHRPs.
The preclinical pharmacology is genuinely solid and reproducible: in rat pituitary cells and in anaesthetised rats and swine, ipamorelin releases GH with potency and efficacy comparable to GHRP-6, and chronic subcutaneous dosing in rats increases longitudinal bone growth and body-weight gain.
An early dose-escalation PK/PD study in healthy male volunteers confirmed that this GH-releasing pharmacology carries over to humans — intravenous ipamorelin produced a brief GH pulse at every dose, with a short ~2-hour half-life — but this is a biomarker/PK result, not a clinical-outcome trial.
The human efficacy story is where honesty matters. Ipamorelin entered clinical development not as a body-composition or anti-aging drug but as a candidate prokinetic for postoperative ileus (the ghrelin receptor drives GI motility).
The pivotal published evidence — a phase-2, multicenter, double-blind, placebo-controlled trial in 114 bowel-resection patients (NCT00672074) — was a NULL result: median time to first tolerated meal was 25.3 h on ipamorelin vs 32.6 h on placebo, a difference that did not reach significance (p = 0.15), and the authors reported no significant differences on key or secondary efficacy endpoints.
The drug was well tolerated, but clinical development for that indication did not advance.
There are no approved human uses, no controlled trials supporting the bodybuilding/anti-aging claims that drive its grey-market sale, and essentially all human consumption today is via unregulated 'research-use-only' injectable vials of unverified purity.
Binds and activates the growth-hormone-secretagogue receptor (GHS-R1a) — the same receptor as the natural hormone ghrelin — on pituitary somatotrophs. Pharmacological profiling with GHRP and GHRH antagonists confirms it works through the GHRP-like (ghrelin) receptor, not the GHRH receptor.
Triggers a pulse of growth-hormone secretion from somatotrophs with efficacy similar to GHRP-6, but — unlike older secretagogues — without meaningfully raising ACTH/ or prolactin, which is the basis of its 'selective' label. Demonstrated in rodent and swine pharmacology.
How Ipamorelin works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
No validated human dose for any physique or anti-aging use. The published human studies were intravenous and hospital-based: an early dose-escalation PK/PD study (4.21-140.45 nmol/kg IV) confirmed a GH pulse, and the phase-2 ileus trial used 0.03 mg/kg IV twice daily. Grey-market subcutaneous use is unstandardized and not endorsed.
Can be taken without food
| Form | Type |
|---|---|
| 💊None (research compound, not for human use) | Recommended |
There is no recommended consumer form. Ipamorelin is a research chemical and a WADA-prohibited substance, not a dietary supplement.
Minimum: 1 weeks
Optimal: 2 weeks
Cycling: Not required
Note: No validated timing — there is no approved human use. Any human use is off-label / grey-market and not endorsed here.
Dose-response data unavailable. The current published research for Ipamorelin does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Reliably triggers a short GH pulse — the core, well-replicated finding in rats and swine, and confirmed in a human PK/PD study where IV ipamorelin released GH at all doses (~2 h half-life). This is a surrogate biomarker effect, not a clinical outcome.
Body-composition, recovery and anti-aging claims are not supported by any controlled human trial — they are extrapolated from animal GH data and anecdote.
The one published human efficacy trial (postoperative ileus) found no significant difference vs placebo on its key or secondary endpoints (p = 0.15).
GH elevation can cause water retention, joint/peripheral edema, tingling, and reduced insulin sensitivity — expected pharmacodynamic effects of any GH secretagogue.
Contraindicated — never studied; GH-axis manipulation is inappropriate in pregnancy.
Avoid — GH/IGF-1 elevation is theoretically growth-promoting.
Avoid — GH secretagogues reduce insulin sensitivity.
Prohibited at all times under the WADA Prohibited List (GH secretagogues).
GH secretagogues raise GH, which antagonises insulin and can worsen glycemic control — may reduce the effect of glucose-lowering therapy.
Studied alongside glucocorticoids in catabolic animal models; the GH-axis and steroid effects on nitrogen/glucose metabolism may interact. No human safety data.
Tip: Expected GH-axis effect; reduce or discontinue. No validated mitigation in unapproved use.
Tip: Monitor glucose; avoid in diabetes/prediabetes.
Tip: Inherent to injecting unregulated research peptides of unverified sterility — a sourcing risk, not a property of the molecule.
Tip: Generally transient; discontinue if persistent.
Timing is flexible for Ipamorelin — consistent daily use matters more than the time of day. No validated human regimen exists.
Ipamorelin should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are water retention / peripheral edema, reduced insulin sensitivity / higher blood glucose, injection-site reactions / infection risk. Use caution if any of these apply to you: Pregnancy and breastfeeding (contraindicated — never studied, GH-axis effects); Active or prior malignancy (GH/IGF-1 elevation is theoretically growth-promoting); Competitive athletes subject to anti-doping rules (WADA-prohibited).
Tirzepatide
Mostly mechanism / observationalAn FDA-approved prescription medication (Mounjaro for type 2 diabetes, Zepbound for obesity and obstructive sleep apnea), not a dietary supplement. Honest appraisal: in head-to-head phase-3 trials it is the most effective approved weight-loss drug to date — up to ~21% body-weight loss over 72 weeks and superior to semaglutide — but it is a real medicine with real risks: a boxed warning for thyroid C-cell tumors, common GI side effects, and pancreatitis/gallbladder signals. Do not source or use it outside a prescription.
It is on the WADA Prohibited List (GH secretagogues are banned at all times). The overall evidence for any human benefit is therefore very weak / emerging, and the realistic appraisal is a pharmacologically interesting molecule whose clinical promise did not pan out.
Ghrelin-receptor activation stimulates gastric and colonic motility via cholinergic excitatory neurons. This is the mechanism that put ipamorelin into clinical trials as a postoperative-ileus prokinetic — an indication where the human trial ultimately failed its endpoint.
Stacking with other GHS (GHRP-6, GHRP-2, CJC-1295) or exogenous GH compounds GH-axis side effects (edema, insulin resistance) with no evidence of added benefit.