Sermorelin + Ipamorelin

The stack combines one peptide from each of the two main families of growth hormone secretagogues. Sermorelin is the first 29 amino acids of human growth hormone-releasing hormone (GHRH), once sold as the prescription drug Geref for children with growth hormone deficiency. Ipamorelin is a five-amino-acid peptide developed in the 1990s that acts on the ghrelin receptor, the same target as older growth hormone-releasing peptides (GHRPs) such as GHRP-6. Neither replaces growth hormone. Each prompts the pituitary to release more of its own, so the body's normal feedback stays in play.

Growth hormone release is controlled by pushes and a brake. GHRH from the hypothalamus is the main push, and somatostatin is the brake. Ghrelin, a hormone made mainly in the stomach, adds a second push through its own receptor, called the growth hormone secretagogue receptor. Sermorelin acts on the GHRH receptor, while ipamorelin acts on the ghrelin receptor and also appears to counter the somatostatin brake.

A common shorthand is that the GHRH side tells the pituitary to make growth hormone and the ghrelin side lets it out. In reality both promote release, through separate signaling routes. Human studies in the 1980s and 1990s found that giving a GHRH together with a ghrelin-type peptide such as GHRP-6 produced a larger growth hormone response than either alone, which is the rationale for this and similar pairings.

Ipamorelin was developed by researchers at Novo Nordisk in the 1990s and described as one of the first selective growth hormone secretagogues. In animal studies, it released growth hormone without the notable rises in the stress hormones ACTH and cortisol seen with GHRP-6 and GHRP-2. Claims that it causes less hunger than GHRP-6 are not well established by controlled human studies. In humans, it reached trials for bowel recovery after surgery, where it did not show a clear benefit over placebo.

No published clinical trial has tested sermorelin and ipamorelin together. Claims about muscle, fat loss, sleep, skin or recovery from this stack come from the general effects of growth hormone and from user reports, not from direct research on the combination.

Reported side effects for each peptide are mostly mild in short studies, but the long-term safety of the combination is unknown. Since both parts raise growth hormone and IGF-1, the general cautions for the growth hormone axis apply, and combining two secretagogues may make those effects more likely. Talk to a qualified clinician before making decisions about any growth hormone-related compound.

This page summarizes the research in plain words. To read the studies yourself: