Ipamorelin is a ghrelin mimetic – it binds to the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHS-R1a) in the pituitary and hypothalamus, stimulating the release of growth hormone. Importantly, it’s very selective: Ipamorelin’s structure allows it to trigger GH release without robustly triggering the release of ACTH (which would make cortisol) or PRL (prolactin). As a result, it creates a pure growth hormone pulse. Upon injection, GH levels rise within minutes, peaking around 20–30 minutes and returning to baseline within 2–3 hours. This pulse can increase IGF-1 levels modestly over time, aiding in muscle growth and fat loss. Because it mimics ghrelin, Ipamorelin can have some ghrelin-like effects (ghrelin is the “hunger hormone”), but Ipamorelin was designed to minimize those – it has very little impact on appetite compared to older GHRPs like GHRP-6, which often caused intense hunger. It also doesn’t cause the sharp, uncomfortable surge in cortisol or prolactin that some peptides (like GHRP-2) do. Essentially, Ipamorelin gives you the benefits of a GH spike (tissue repair, fat breakdown, better sleep) in a controlled manner. Many studies and anecdotal reports indicate that Ipamorelin used pre-bed leads to more physiological GH patterns during sleep (mimicking the body’s natural nightly GH release). This supports muscle recovery, improves sleep architecture, and can even have cosmetic benefits (GH is known to support skin and hair health through collagen production). When paired with a GHRH analog, the GH pulse both intensifies and lengthens – GHRH sets the stage, and Ipamorelin provides the secretagogue trigger, a combination known to be one of the most effective non-HGH ways to elevate GH levels.