GHRP-2

A synthetic growth hormone-releasing peptide developed in the 1990s. Kaken Pharmaceutical's version was approved in Japan in 2004 as a diagnostic test for growth hormone deficiency.

It activates the ghrelin receptor in the pituitary and hypothalamus, causing a strong, short release of growth hormone. Paired with GHRH, which acts through a different receptor, the response is larger. It also modestly raises ACTH, cortisol and prolactin, and increases appetite.

Japanese trials in 227 patients and a 503-patient post-marketing survey confirmed its value as a single-dose test for severe growth hormone deficiency. Small human studies found the growth hormone response faded with repeated administration over several days, while a 30-day continuous infusion in older adults kept it elevated and raised IGF-1. One study in 7 men found food intake rose about 36%. Pediatric short-stature trials never led to approval for ongoing use. Long-term safety and metabolic effects are unknown.

Japanese labeling lists a warm sensation, abdominal rumbling and raised white-cell count as common, with a 37.9% adverse-reaction rate before approval. Similar drugs have caused pituitary bleeding in people with pituitary tumors. FDA cites reported serious adverse events, including infection, pancreatitis and higher insulin needs, with causality not established.

Not approved in the US. Approved in Japan only as a one-time IV diagnostic (GHRP KAKEN 100). FDA lists it in 503B Category 2 (significant safety risk) and 503A Category 3 (insufficient information), so it is not compoundable. WADA prohibits it at all times under S2.4. Status as of October 2026.