GHRP-6

Yes, at raising growth hormone in controlled human trials — this is a well-established, dose-dependent effect. In one trial, 18 healthy men given a single injection showed peak GH levels of 7.6, 16.5, and 68.7 µg/L at doses of 0.1, 0.3, and 1 µg/kg respectively, against 1.2 µg/L on placebo. GHRP-6's other claimed benefits, like fat loss or body-composition change from repeated use, are far less studied; the trials that exist measured single-dose or short-course hormone responses, not weeks-long outcomes on muscle or fat.

Yes — GHRP-6 produces the strongest appetite stimulation among the GH-releasing peptides in this family, working through the same hypothalamic hunger circuits (NPY/AgRP neurons) that ghrelin itself activates. The hunger typically starts 20 to 30 minutes after injection and lasts 1 to 2 hours. This is why GHRP-6 has also been researched for appetite-wasting conditions like cancer cachexia, where stimulating appetite is the goal rather than a side effect.

Poorly, based on the one study that tested it. Ten healthy men received oral doses of 30, 100, or 300 µg/kg — the highest being 300 times the effective injected dose by weight — and even that produced a lower peak GH (18 µg/L) than a modest 1 µg/kg injection (26 µg/L). The two lower oral doses barely beat placebo. No oral GHRP-6 product came out of that single one-day study, so tablets sold as GHRP-6 do not have supporting human efficacy data behind them.

The evidence base does not include a formal half-life or clearance figure for GHRP-6. What is documented is the speed of its biological effects: appetite starts rising within 20 to 30 minutes of injection, and in the dose-finding trial, growth hormone was measured as an acute peak from a single injection. There is no published data on how long repeated dosing needs to run before an effect like fat loss or lean mass would show up.

Beyond intense hunger, GHRP-6 raises cortisol by 20 to 40% and prolactin by 15 to 30% at GH-stimulating doses — larger increases than GHRP-2 or ipamorelin produce. Other reported effects include water retention in the face and extremities that usually eases within 2 to 4 weeks, mild injection-site reactions, tingling or numbness with sustained use, brief dizziness or headache after dosing, and stomach discomfort from increased gastric acid secretion.

No major regulator — not the FDA, not the EMA — has approved GHRP-6 for any clinical use; it remains an investigational research compound, studied under institutional review board oversight but never taken through phase 3 approval. WADA prohibits it under category S2 (peptide hormones and growth factors), both in and out of competition — GHRP-6 was among the first GH secretagogues added to that list.

Self-administration circulates at 100 to 200 µg per injection, two to three times a day — roughly 1.1 to 2.9 µg/kg for a 70-90 kg adult. That pattern of repeated daily injections has never actually been tested in a trial: the published human research dosed it once or over just a couple of days, by vein, mouth, or nose, so there is no study behind the repeated-injection regimen people actually use.