GHRP-6 vs Ipamorelin
The original GHRP against the one that replaced it. What did ipamorelin fix, and when is the old one still the right pick?
Reviewed by the amino101 editorial team. , first published .
GHRP-6 is the first growth hormone releasing peptide, a hexapeptide from 1984 that releases growth hormone through the ghrelin receptor and brings intense hunger, cortisol and prolactin along with it. Ipamorelin is a pentapeptide developed by Novo Nordisk in the 1990s to keep the growth hormone release and drop the rest. In the original animal work it matched GHRP-6 for growth hormone output with no meaningful rise in ACTH, cortisol or prolactin, and in humans it does not produce the sharp appetite GHRP-6 is known for. That selectivity is why ipamorelin became the default GHRP in community protocols and GHRP-6 became a niche tool for people who want to eat more. Neither is approved anywhere. Ipamorelin reached phase 2 before Novo Nordisk dropped it; GHRP-6 never entered drug development. Both are prohibited by WADA. Under the February 2026 HHS announcement on compounding, ipamorelin is generally reported as returning toward Category 1 while GHRP-6 is expected to stay restricted, though neither is final. This is an educational comparison.
| GHRP-6 | Ipamorelin | |
|---|---|---|
| Typical dosage | 100 to 300 mcg | 100 to 300 mcg |
| Frequency | 1 to 3 times daily | 1 to 3 times daily |
| Route | Subcutaneous, Intranasal | Subcutaneous |
| Half-life | roughly 30 to 60 minutes in plasma (estimated) | about 2 hours in plasma |
| Cycle | 8 to 12 weeks | 8 to 16 weeks |
| Research level | Well researched | Well researched |
| Human trials | Randomized trials | Randomized trials |
| Status | Investigational, not approved anywhere. Prohibited by WADA under S2. | Investigational, not FDA approved (Phase 2 trials completed, not pursued) |
| Effects timeline | hunger within 30 minutes of the first dose, deeper sleep 1 to 2 weeks, IGF-1 rise by 4 weeks, weight gain and recovery 4 to 12 weeks | deeper sleep 1 to 2 weeks, IGF-1 rise on bloodwork by 4 weeks, recovery and body composition 2 to 3 months |
Key differences
GHRP-6 vs Ipamorelin dosage
Dosage patterns reported in research and community protocols, by goal. Taken from each compound page. Not a prescription.
| Goal | Dosage | Frequency |
|---|---|---|
| Stacked with a GHRH analog | 100 mcg | once daily before bed, with 100 mcg CJC-1295 no DAC |
| Appetite before meals | 100 to 200 mcg | 2 to 3 times daily, 20 to 30 minutes before meals |
| Solo nightly dose | 200 to 300 mcg | once daily before bed |
| Three pulse protocol | 100 mcg | 3 times daily, on waking, after training, before bed |
| Goal | Dosage | Frequency |
|---|---|---|
| Solo nightly dose | 200 to 300 mcg | once daily before bed |
| Stacked with a GHRH analog | 100 mcg | once daily before bed, with 100 mcg Mod GRF 1-29 |
| Three pulse protocol | 100 mcg | 3 times daily, on waking, after training, before bed |
| Recovery focus | 100 to 200 mcg | twice daily, after training and before bed |
Convert any of these to syringe units in the dosage calculator.
Side effects compared
- ▲Intense hunger shortly after a dose
- ▲Flushing, headache or lightheadedness in the first hour
- ▲Water retention and puffy hands at higher doses
- ▲Tingling in the fingers when stacked heavily
- ▲Raised cortisol, felt by some as restlessness or poorer sleep from daytime doses
- ▲Headache, flushing, or lightheadedness shortly after a dose
- ▲Water retention and puffy hands at higher doses
- ▲Tingling in the fingers when stacked heavily
- ▲Mild appetite increase in some people
- ▲Injection site redness or itching
Which should you choose?
GHRP-6 fits someone whose problem is eating enough. Reported protocols use 100 to 200 mcg, 20 to 30 minutes before meals, two or three times a day, timed so the meal lands as the hunger peaks, with a 100 mcg bedtime dose alongside a GHRH analog for the growth hormone pulse. Expect cortisol and prolactin to rise after every dose, keep the run to 8 to 12 weeks, and skip it entirely on a fat loss plan or alongside a GLP-1 drug.
Ipamorelin fits anyone who wants growth hormone release without side effects. Commonly reported at 100 mcg paired with CJC-1295 no DAC before bed on an empty stomach, or 200 to 300 mcg alone. It is the GHRP for longer runs, for people with sleep, mood or libido concerns, and for anyone who would rather not be hungry at midnight. It is also the one with phase 2 human safety data.
Ipamorelin for nearly everyone. It releases growth hormone through the same receptor without the hunger, cortisol or prolactin, its 2 hour half-life is easier to time, and it has the only phase 2 data in the GHRP class. Running it for 8 to 16 weeks at 100 mcg alongside CJC-1295 no DAC is the standard secretagogue protocol for a reason; see the CJC-1295 and ipamorelin stack. GHRP-6 is the right call in one situation: when hunger is the goal. Someone who cannot eat enough to gain, or who wants a dependable appetite signal before meals, gets that from GHRP-6 and from nothing else in this family. The older pairing is written up at the GHRP-6 and CJC-1295 stack. The one thing GHRP-6 does not do is build more muscle than ipamorelin; the growth hormone output is in the same range, and the extra gains people report come from the extra calories. Both compounds are unapproved and prohibited in sport, and this page is educational rather than a recommendation.
Stacking: Not combined, since they share a receptor. Some people alternate: GHRP-6 before meals when hunger is wanted, ipamorelin at bedtime when it is not. Either is paired with CJC-1295 no DAC at 100 mcg each.
GHRP-6 is the original growth hormone releasing peptide, a six amino acid ghrelin receptor agonist that produces a solid growth hormone pulse together with intense hunger and a rise in cortisol and prolactin. People use it when they want appetite as much as growth hormone, usually stacked with a GHRH analog.
Ipamorelin is a pentapeptide that triggers growth hormone release through the ghrelin receptor without the cortisol, prolactin, or hunger spikes seen with older GHRPs. It is the most popular GHRP in the community, usually stacked with a GHRH analog.
GHRP-6 vs Ipamorelin: frequently asked
Is ipamorelin better than GHRP-6?
For growth hormone release with the fewest side effects, yes. Ipamorelin was designed as a selective version of the GHRP idea: the same receptor and a comparable pulse at 100 mcg, with no meaningful cortisol, prolactin or hunger. GHRP-6 is better only at one thing, making people hungry, which is a feature for some users and a problem for everyone else.
Why did ipamorelin replace GHRP-6?
Because the side effects of GHRP-6 are the compound. Every dose brings sharp hunger and a cortisol and prolactin rise, which matter over a 12 week run. When Novo Nordisk published ipamorelin in 1998 as the first selective growth hormone secretagogue, the community had a GHRP that could be stacked with a GHRH analog and run for months without those trade offs. The ipamorelin vs CJC-1295 page covers why that pairing became the default.
Does GHRP-6 build more muscle than ipamorelin?
Not through growth hormone. At 100 mcg both release a similar amount, and neither has a human body composition trial. The difference people notice on GHRP-6 is that they eat more, and on a gaining phase that is what drives weight gain. If calories are already in place, there is no muscle advantage to the older compound. For the bigger question of what secretagogues can and cannot do, see peptides vs steroids.
Can you take GHRP-6 and ipamorelin together?
They are alternated rather than combined. Both act on the ghrelin receptor, so injecting them at the same time adds little release and all of the GHRP-6 side effects. The common split is GHRP-6 before a meal when hunger is wanted and ipamorelin before bed when it is not, each at 100 mcg with CJC-1295 no DAC.
Which is better for sleep, GHRP-6 or ipamorelin?
Ipamorelin. Both produce deeper sleep reports within 1 to 2 weeks from the bedtime pulse, but GHRP-6 also raises cortisol after the dose and leaves people hungry at the moment they are trying to fall asleep. Neither has a sleep trial; the reports are community experience. The sleep angle is covered more fully at best peptides for sleep.
Is GHRP-6 legal?
It is not approved as a drug anywhere and is sold as a research chemical. In the US it has been in FDA Category 2 since 2023, and reports on the February 2026 HHS announcement list it among the peptides expected to stay restricted, while ipamorelin is generally reported as returning toward Category 1. None of that is final. Both are prohibited by WADA under S2, so neither is an option for tested athletes.
Related reading
Pulsatile growth hormone release
Visceral fat loss with growth hormone support
Weight loss while limiting muscle loss
Growth hormone release with appetite support
One is a GHRP, one is a GHRH analog. Why are they compared, and why are they usually combined?
The two halves of the most popular GH stack. What does each one do, and which CJC-1295 are you actually buying?
Sources
- Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998
- On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology, 1984
- Phase 2 study of ipamorelin for the management of postoperative ileus after bowel resection. Neurogastroenterology and Motility, 2014