Hexarelin

Yes, for acutely raising growth hormone — hexarelin produces the highest peak GH levels documented among peptide GH secretagogues, up to 50 to 90 ng/mL after a single dose. In a human dose-finding study, half the peak effect appeared at 0.48 µg/kg IV and the response plateaued around 1 µg/kg. This acute potency does not hold up with repeated use, and hexarelin's other claimed benefits, like fat loss, have far less direct human evidence than its GH-releasing effect.

Hexarelin desensitizes the receptor it works through faster than other GH secretagogues. In a 16-week trial in healthy elderly people dosed twice daily, the GH response fell from 19.1 to 13.1 within a week, to 12.3 by week 4, and to 10.5 by week 16 — roughly half the starting response — while IGF-1 and IGFBP-3 never moved at all over 20 weeks. The response did recover to 19.4 after four weeks off the drug, which is the basis for cycling protocols, though specific on/off durations people use haven't themselves been tested.

In rodent heart-attack models, yes — hexarelin reduced infarct size, cardiac fibrosis, and cell death, and improved heart function, working through a separate receptor (CD36) rather than through growth hormone. In humans it has been tested in only one small study: a single acute dose in 7 healthy men with no heart disease, where it raised left ventricular ejection fraction from 64.0% to 70.7%. No trial has tested hexarelin in actual heart-failure patients.

Self-administration circulates at 100 µg per injection, one to three times a day regardless of body weight — about 1.1 to 1.4 µg/kg for a 70-90 kg adult — typically in cycles of 12 weeks on and 4 weeks off. The 4-week break is borrowed from the trial showing GH response recovers after 4 weeks without the drug, but nobody has actually tested a 12-week-on protocol; the trial that established the desensitization pattern only ran 16 weeks continuously.

Beyond the fading GH response itself, hexarelin raises cortisol by 20 to 40% and stimulates prolactin at GH-stimulating doses. It also causes moderate appetite stimulation — between GHRP-6 (stronger) and ipamorelin (weaker) — water retention that typically eases over 2 to 4 weeks, mild injection-site reactions, and transient facial flushing or warmth lasting 15 to 30 minutes after dosing.

Hexarelin reached phase 2 clinical trials in Europe for both growth hormone deficiency and cardiac applications but was never approved by the FDA or any major regulator, and did not advance to phase 3. It remains classified as an investigational research compound. WADA prohibits it under category S2 (peptide hormones and growth factors), banned both in and out of competition.

Barely. In a study measuring how much of a dose actually reaches the bloodstream by different routes, subcutaneous injection delivered about 77%, nasal spray about 4.8%, and swallowing only about 0.3% — meaning an oral dose would need to be roughly 250 times larger than an injected one to deliver a comparable amount into circulation. That single 1994 study never led to an approved nasal or oral hexarelin product.