Ipamorelin: the gentle GH peptide.

Ipamorelin is a small, selective growth hormone secretagogue — a peptide that asks the pituitary to release growth hormone, with a reputation for being one of the cleaner compounds in its class. Often paired with CJC-1295, it is one of the most-discussed peptides in the GH-axis category.

What it is

Ipamorelin is a synthetic pentapeptide — just five amino acids long, making it one of the smaller peptides commonly discussed in research circles. It belongs to a class called growth hormone secretagogues: compounds that stimulate the pituitary gland to release growth hormone.

It works by mimicking the action of ghrelin, a natural hormone in the body. Ghrelin is famous for its role in appetite, but it also signals through receptors on the pituitary to trigger GH release. Ipamorelin binds those same receptors — prompting GH release — but unlike full ghrelin mimetics, it appears to do so with much less effect on appetite, cortisol, or prolactin in research.

Why "gentle" or "selective"

Within the broader category of GH-releasing compounds, ipamorelin has a reputation for being relatively clean. Other peptides in the class — like GHRP-2, GHRP-6, and hexarelin — also stimulate GH release, but in research literature they have been associated with larger increases in cortisol (the stress hormone), prolactin, or appetite.

Ipamorelin appears, based on the available preclinical and limited clinical data, to be more selective: it stimulates GH release without nearly the same impact on those other hormones. That is part of why it is often discussed as a baseline reference compound for people exploring the GH-axis category.

Why it is often paired with CJC-1295

Ipamorelin and CJC-1295 work on the same overall system — GH release from the pituitary — but through complementary mechanisms. CJC-1295 acts on the GHRH receptor (the same pathway tesamorelin uses); ipamorelin acts on the ghrelin/GHS receptor. When used together in research contexts, they produce additive effects greater than either alone, which is why the combination is so frequently discussed.

Timing is also commonly discussed: GH release is normally highest during deep sleep, so many community references mention timing ipamorelin (or the ipa+CJC pair) for bedtime to align with the body's natural GH-release window.

Where it sits

Ipamorelin is one of the most commonly-referenced compounds in the GH peptide conversation, partly because it is small, selective, and has a relatively clean reputation in research. It also illustrates a useful concept: there are multiple ways to ask the pituitary to release growth hormone, and different compounds target different parts of that signaling system.

If you want the dosing math for ipamorelin, the calculator handles it (a 5mg vial in 2mL with a 100mcg nightly reference is common). And the peptide library shows how it sits alongside the other GH-axis compounds like CJC-1295, tesamorelin, and the broader category.