Ipamorelin: a ghrelin receptor agonist selected for what it does not do
A five-amino-acid peptide developed to release growth hormone without the cortisol and prolactin rise that earlier compounds in its class produced. The selectivity is the reason it displaced them, and it is also the clearest thing anyone can say about it.
Regulatory status. Research compound — no FDA approval. Not for human use label. That is the app’s own field, reproduced here rather than summarised. It means no regulator has reviewed a manufacturer’s evidence for identity, purity, potency or safety in people for this compound, so nothing below is a marketing claim about a product you can buy.
Purity, identity and concentration are therefore unverified by anyone but whoever made the vial. The storage rule in the fact box below is general practice for this formulation rather than a specification for a particular product: General handling practice for this formulation. Your supplier’s own insert or COA overrides anything here.
This page names no vendor, no clinic and no testing service, and there is no discount code anywhere on this site — the moment a page like this recommends where to buy, it stops being information.
- Also known as
- Ipa, Selective GHRP
- Class
- Peptide
- Regulatory status
- Research compound — no FDA approval. Not for human use label.
- Modelled half-life
- 2 h
- Time to peak
- 42 min
- Formulation
- Aqueous (reconstituted powder)
- Before mixing
- Sealed powder tolerates room temperature in transit, but keep it refrigerated at 2–8 °C (36–46 °F) for anything beyond a few weeks, or frozen for months. Keep it dark — the carton it shipped in is doing a job.
- After mixing
- Once reconstituted with bacteriostatic water: refrigerate at 2–8 °C and use within about 28 days. The benzyl alcohol in bacteriostatic water is what buys that window — plain sterile water has no preservative, so a vial mixed with it should be treated as one sitting only. Kits are usually ten vials: only the one you mixed is on that 28-day clock — the sealed ones keep their own, much longer shelf life, so store them as powder, not as solution.
- What ruins it
- Do not freeze a reconstituted vial. Repeated freeze–thaw is one of the more reliable ways to degrade a peptide.
- Handling caveat
- General handling practice for this formulation. Your supplier’s own insert or COA overrides anything here.
Two receptors, one growth hormone pulse
Growth hormone release is governed by two opposing hypothalamic signals: GHRH, which stimulates it, and somatostatin, which suppresses it. Ghrelin — the stomach hormone associated with hunger — acts at a third site, the growth hormone secretagogue receptor, where it both stimulates release and reduces somatostatin tone. Ipamorelin is a synthetic agonist at that receptor. It is not a GHRH analogue and does not work the same way one does.
That is the pharmacological basis for pairing it with a GHRH analogue such as modified GRF(1-29). Two different receptors, two complementary actions on the same pulse: the release signal is raised while the brake is eased. The combined effect on a GH pulse is reported as greater than either produces alone, and that finding comes from human physiology studies of the mechanism rather than from trials of the specific products people use.
What "selective" actually refers to
The earlier compounds in this class — GHRP-6, GHRP-2, hexarelin — release growth hormone effectively and also raise cortisol and prolactin to varying degrees, because the receptor's signalling is not confined to the GH axis. Established clinical use Ipamorelin was characterised as producing GH release with minimal effect on ACTH, cortisol and prolactin at effective amounts, and that separation is the property it was selected for and the reason it is preferred.
Selectivity is dose-dependent rather than absolute, and the appetite effect is not eliminated. Stimulating a ghrelin receptor does what stimulating a ghrelin receptor does; the app's own drawbacks list notes mild hunger stimulation, and that is a predictable consequence of the mechanism rather than a surprise. It is markedly less pronounced than with an orally active agonist that occupies the receptor continuously.
Animal-only or theoretical What is not established is anything downstream. Ipamorelin was developed by a pharmaceutical company and taken into human study before being discontinued; there is no approval and no controlled trial supporting the uses it is put to now. The GH pulse is real and measurable. Whether repeatedly amplifying pulses in a person with a normal axis changes body composition, recovery or sleep in a way that matters is not something the literature answers.
Timing, monitoring and what the numbers mean
The app models a two-hour half-life, which is long enough to cover a pulse and short enough that the compound is gone well before morning. Administration is described in the fasted state, usually before sleep, because insulin and glucose blunt GH release and the largest natural pulse occurs in slow-wave sleep. Those constraints come from the physiology of the axis rather than from this peptide.
IGF-1 is the marker on the app's panel and the only practical way to see whether anything happened, since a serum growth hormone drawn at an arbitrary time reports mostly where in a pulse the needle went. IGF-1 integrates exposure over a longer window — the IGF-1 page covers why the reference range is age-dependent and what a change in it does and does not mean. Fasting glucose sits beside it because raising growth hormone reduces insulin sensitivity.
There is no approved product, so identity, purity and concentration rest entirely with whoever made the vial, and no vendor or testing service is named anywhere on this site. Anything experienced while using it — and a rising fasting glucose in particular — belongs with a clinician who has the whole picture.
The curve, the accumulation ratio and the peak-to-trough figures have a page of their own: Ipamorelin half-life and steady state.
The dosing rows the app records
Off-label or community practice Reproduced from the app’s reference so you can see what it holds, not as a recommendation. Which row applies to a particular person, if any, is a clinical decision this page does not make — and rows describing supraphysiological or post-cycle use are filtered out before this table is built, so what you see here is a subset.
| Label | Amount | Route and frequency | Duration recorded |
|---|---|---|---|
| Starting | 100-150mcg | Once daily 30 min before bed fasted | 3 months on / 1 month off |
| Optimized | 200-300mcg | Twice daily fasted AM and pre-bed | 3-6 months |
What the app monitors alongside it
The panel below is the app’s own monitoring note for Ipamorelin, verbatim. The analytes in it that have a page here are linked; those pages cover what each one measures, which assay produced it and how to read a trend.
- Monitoring panel
- IGF-1 at baseline and every 3 months. Fasting glucose.
Drawbacks and risks the app records
From the app's own entry. The hunger item is mechanism rather than side effect, and the monitoring items are the ones that show up on paper rather than in how someone feels.
- Short half-life requires precise timing
- Mild hunger stimulation
- Requires refrigeration
- Limited long-term human data
- IGF-1 monitoring recommended
Interaction rules that name Ipamorelin
From the app’s interaction data, filtered so no rule naming a compound this site does not publish appears. Not exhaustive, and not a safety clearance: a combination that is not listed is one nobody has documented here, which is not the same as one that is fine. The combination checker has the rest.
Excellent GHRH + GHRP Synergistic Pairing
Tesamorelin (GHRH analogue) and Ipamorelin (GHRP) work synergistically to produce larger GH pulses than either alone — the GHRH primes the somatotrophs and the GHRP amplifies the pulse. This is the FDA-validated compound type pairing with the most evidence.
What to watch: IGF-1 every 3 months, fasting glucose, HbA1c.
Gold Standard GH Secretagogue Pairing
CJC-1295 (GHRH analogue) and Ipamorelin (selective GHRP) are the gold standard GH secretagogue combination. CJC-1295 primes pituitary somatotrophs while Ipamorelin triggers GH release with minimal cortisol or prolactin elevation. Always pair these — neither is as effective alone.
What to watch: IGF-1 every 3 months. Fasting glucose. No prolactin monitoring needed with Ipamorelin.
Questions people actually ask
How is it different from MK-677?
Both act at the ghrelin receptor. Ipamorelin is an injected peptide with a two-hour half-life that produces a discrete pulse; MK-677 is an orally active non-peptide with a day-long half-life that produces sustained elevation. Sustained versus pulsatile is a real pharmacological difference, and it is the main reason their side-effect profiles differ. MK-677 has its own page here.
Why is it always paired with a GHRH analogue?
Because they act at different receptors and their effects on a growth hormone pulse combine. That synergy is established in human physiology studies. The specific pairing people use has not been through a controlled trial, which is a different statement from saying it does not work.
Does it raise cortisol?
Far less than the earlier compounds in its class at effective amounts, which is the property it was developed for. "Minimal" is not "none", and selectivity narrows as the amount rises. Cortisol and prolactin are not on the app's routine panel for this compound for that reason.
How long does one dose last?
The app models about two hours, so the peptide is cleared within a working day. The GH pulse it triggers and the IGF-1 response that follows outlast it considerably. The half-life page has the curve.
Where the load-bearing numbers come from
Named rather than linked. Publisher URLs move, and a citation that resolves to a 404 two years from now is worse than one you can search for by name — every entry below is findable from the title and year alone.
- Selectivity for GH release over ACTH and prolactin
- The original characterisation of ipamorelin in the growth hormone secretagogue literature, published in the late 1990s
- Ghrelin receptor signalling and somatostatin tone
- Standard endocrinology references on the GH secretagogue receptor
- Synergy with GHRH analogues
- Human physiology studies of combined GHRH and secretagogue administration
- Modelled half-life
- app.html’s TL_PK entry
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