Ipamorelin
Ipamorelin is a selective pentapeptide growth-hormone secretagogue (a ghrelin/GHS-R agonist) that triggers a clean GH pulse with little effect on cortisol, prolactin or appetite. This selectivity makes it the most commonly used GHRP for body-composition purposes, usually stacked with a GHRH analogue. Human evidence is limited to early pharmacology; physique use is anecdotal.
01 Overview
Ipamorelin mimics ghrelin at the GHS-R1a receptor to release growth hormone, but unlike older GHRPs it does not meaningfully raise cortisol or prolactin and causes far less hunger than GHRP-6. It is short-acting and dosed one to three times daily.
It is frequently combined with modified GRF(1-29) or CJC-1295 so that GHRH-receptor and ghrelin-receptor pathways reinforce each other. Clinical development for indications such as post-operative ileus did not yield an approved product, and there is no controlled human efficacy data for physique use.
02 Mechanism
Selective agonist of the growth-hormone secretagogue receptor (GHS-R1a, the ghrelin receptor) on pituitary somatotrophs, evoking a pulse of GH release with minimal cortisol, prolactin or appetite effect.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal (non-medical) | 100–300 mcg | SubQ | ~100-300 mcg per injection, often 1-3x/day; commonly paired with a GHRH analogue. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Raised GH (clean pulse)Selective GH release without notable cortisol/prolactin rise; human physique magnitudes not well quantified. | Preclinical | ||
| Fat loss and recoveryReported modest fat loss and improved recovery; not established in controlled trials. | Anecdotal | ||
| Improved sleepUsers report deeper sleep, consistent with GH-axis stimulation. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Injection-site reactionsLocal redness or swelling. | Mild | Common | Anecdotal | |
| Mild water retentionSlight puffiness or wrist tingling from GH elevation. | Mild | Uncommon at typical doses | Anecdotal | |
| Transient head rush / light-headednessBrief dizziness shortly after injection. | Mild | Uncommon | Anecdotal |
06 Commonly used with
What ipamorelin is combined with, and why. This is about intent rather than safety — the interactions table below covers what is dangerous. Nothing here is listed without what it costs.
| Compound | Frequency | Purpose & trade-off |
|---|---|---|
| Stacked compounds | ||
| CJC-1295GHRH (often DAC or mod-GRF 1-29) | The standard GHRP+GHRH pairing — ipamorelin (a ghrelin-mimetic GH releaser) is combined with a GHRH analogue so the two act on different receptors and produce a larger, more physiological GH pulse than either alone.Trade-off: The bigger GH pulse also means more water retention, tingling/numbness and reduced insulin sensitivity, and human outcome data for the combo is thin. | |
| Somatropinlow-dose HGH | Occasionally layered so exogenous GH provides a baseline while ipamorelin adds a pulsatile component.Trade-off: Exogenous GH suppresses the endogenous axis the secretagogue is trying to stimulate, so the two partly work against each other while stacking cost and side effects. | |
| IGF-1 LR3downstream mediator | Added to supply the IGF-1 that GH normally drives, in hopes of stronger anabolic/recovery effects than raising GH alone.Trade-off: Directly dosing IGF-1 on top of raised GH pushes hypoglycaemia risk and theoretical growth-of-anything (including tumours) concerns, with no human safety data at these uses. | |
| Support & ancillaries | ||
| Metformin or careful carb timingglucose management | Used to counter the insulin-desensitising effect that sustained GH elevation from ipamorelin can cause.Trade-off: It adds GI side effects and blunts some of the fat-loss signalling, and does not remove the underlying glucose-handling stress from chronic GH stimulation. | |