Ipamorelin — why it is considered the cleanest GHRP for research

If you're researching GH secretagogues and trying to decide between the GHRPs, ipamorelin comes up as the recommended starting point almost universally. Here's why.

What makes ipamorelin different from other GHRPs:
Ipamorelin is a selective growth hormone secretagogue — it stimulates GH release from the pituitary without significantly affecting cortisol or prolactin levels. This is the key distinction. GHRP-6 and GHRP-2 both stimulate GH effectively, but they also increase cortisol (a stress hormone) and prolactin to varying degrees. Ipamorelin provides the GH pulse with minimal hormonal side effects.

The hunger factor:
GHRP-6 is notorious for causing intense hunger within 15-20 minutes of injection. This is because it strongly activates ghrelin receptors. GHRP-2 causes moderate hunger. Ipamorelin causes little to no hunger increase in most researchers. If appetite stimulation is a problem for your research goals (particularly if you're also running GLP-1 peptides), ipamorelin is the obvious choice.

Standard ipamorelin protocol:
100-200mcg per injection, 2-3 times daily. Best paired with Mod GRF 1-29 (CJC-1295 no DAC) at 100mcg per injection for synergistic GH release. Timing: first thing in the morning (fasted), post-workout, and before bed. The pre-bed dose is particularly valued because it amplifies the natural GH surge that occurs during deep sleep.

Fasting requirement:
GH release is blunted by elevated blood sugar and insulin. For optimal results, ipamorelin should be administered on an empty stomach — at least 2 hours after eating, and don't eat for at least 15-20 minutes after injection. This is one of the most commonly violated protocol details and likely explains why some researchers report underwhelming results.

What to measure:
IGF-1 blood levels are the standard marker for assessing GH peptide effectiveness. Get a baseline IGF-1 before starting, then retest at 4-6 weeks. A meaningful increase in IGF-1 suggests the peptide is working and your protocol is sound. Sleep quality improvements are often the first subjective sign — many researchers report deeper sleep within the first week.

Duration and cycling:
Most researchers run GH peptide protocols for 3-6 months. There's debate about whether cycling is necessary. Some researchers run continuous protocols; others cycle 5 days on / 2 days off or 3 months on / 1 month off. The rationale for cycling is to prevent pituitary desensitization, though the evidence for this with ipamorelin specifically is limited.

Ipamorelin isn't the strongest GHRP — GHRP-6 produces a larger GH pulse. But it's the most side-effect-friendly and the most versatile for stacking. For most researchers, that trade-off is worth it.