Hexarelin

Hexarelin is a lab made chain of six of the small building blocks that proteins are made from, and short chains like this are called peptides. It is also called examorelin. The chain reads His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 and it is listed in the public chemical database PubChem under identifier 6918297. It is sold as a powder in a small glass bottle, mixed with liquid and injected under the skin, and what it is bought on is that it makes the body release more of its own growth hormone, the messenger the body uses for growth and repair. The compound standing closest to it is GHRP-6, growth hormone releasing peptide 6, which differs by a single substitution at the second position along the chain, where GHRP-6 carries D-tryptophan and this one carries D-2-methyl-tryptophan, one methyl group apart, and GHRP-6's evidence gets quoted as this one's routinely. What is unusual about it in this reference is that somebody ran the long study: 12 healthy elderly adults, under the skin, at about the amount that circulates, for 16 weeks. The response fell roughly 45 percent and nothing underneath it moved.

It presses the same docking point on a cell that the body's own hunger hormone ghrelin uses, called the growth hormone secretagogue receptor 1a, and that prompts the release of the body's own growth hormone. In people it is not selective about what else comes out with it. Massoud, Hindmarsh and Brook gave healthy adult men 0 to 1.0 micrograms for every kilogram of body weight into a vein and measured more than growth hormone: growth hormone levelled off at 140 milliunits per litre, prolactin, the hormone behind milk production, rose by up to 180 percent above where it started, and cortisol, the main stress hormone, took a step up of about 40 percent at half a microgram per kilogram. The part that decides the compound is what continued dosing does to that response. Over 16 weeks of injections under the skin, the total growth hormone released after a test dose, measured as the area under the curve, fell from 19.1 to 10.5 micrograms per litre times hours, roughly 45 percent, having already dropped to 13.1 by week one before anything reached significance. Four weeks after the last injection the response had returned to 19.4, so the fading is partial and it reverses. Across the same 20 weeks insulin like growth factor 1, the blood marker growth hormone normally drives up, did not change significantly, nor did the protein that carries it about, insulin like growth factor binding protein 3, and total body fat, lean body mass and bone mineral density had not changed at week 16 either. The response faded, and there was arguably nothing downstream for the fading to take away. There is a second receptor story and its direction runs the opposite way from how it is sold. Bodart and colleagues labelled rat heart membranes with a radioactive version of the compound and pulled out a binding protein of about 84 kilodaltons, the unit molecular sizes are counted in, whose opening sequence read identically to rat CD36, with the response absent in hearts from mice bred without CD36. In those same rat hearts the compound raised the pressure needed to push blood through the heart's own vessels as the amount went up, which is narrowing rather than widening, and that paper closes by suggesting CD36 may be involved in the coronary vessel spasm of high cholesterol and artery disease. No human study connects this compound's heart effect to CD36.

This entry does not survey what buyers say they are after, so what follows is what the selling is built on and where each piece came from. The growth hormone release itself is not in dispute. The heart claims rest on five human studies, every one of them a single dose into a vein, almost always 2.0 micrograms per kilogram: seven male volunteers given either lab made human growth hormone or this compound, where both raised growth hormone similarly and only this one raised the share of blood the main pumping chamber pushes out with each beat, 70.7 percent against 64.0 percent, a result the same group found again in men whose own growth hormone was deficient, and 24 men with narrowed heart arteries dosed during bypass surgery, where pumping rose from ten minutes and blood output stayed up for as long as 90 minutes while growth hormone, growth hormone releasing hormone and dummy treatment did nothing. The tidy anti-atherosclerosis results that get attached belong to EP-80317, a different compound from the same family that does not release growth hormone at all, and its mouse data is not this one's. The cycling pattern is part of the sales story too, about 6 to 8 weeks on with a 4 to 8 week break, framed explicitly as a way of managing the fading response.

Two mistakes, and the first is what the break in the cycle is for. Breaks are sold as a way to manage the fading response, which concedes the central finding rather than answering it, and the thing those breaks protect is a growth hormone spike that, in the one study measuring it at that amount and by that route, never produced a rise in insulin like growth factor 1 to begin with. Sixteen weeks in, the response was down roughly 45 percent and body fat, lean mass and bone density had not moved. The second is the heart evidence, which is genuinely good and is about something narrower than the page it appears on. All five human heart studies gave a single dose into a vein, almost always 2.0 micrograms per kilogram, and the author could find no repeat dose human heart study and no human heart data at all by the route people actually inject. The long version of that story is rats, at 80 micrograms per kilogram twice daily for 21 days, roughly 53 times the 1.5 micrograms per kilogram twice daily of the only long human study, before any adjustment for the size difference between a rat and a person. The tidy anti-atherosclerosis results belong to EP-80317, a different compound that does not release growth hormone at all. And the receptor paper people cite for the heart claims is the one in which the compound narrowed coronary vessels. Underneath both mistakes sits a third: GHRP-6 is one methyl group away at a single position, and its evidence gets read across as this compound's.

Very little has been published either way, and the entry is careful about whose emptiness that is. It carries no side effect tally from the 16 week study. The two short courses, 8 days up the nose and 15 days by mouth, caused no side effect and did not move prolactin or cortisol. Single doses into a vein are a different picture: prolactin rose by up to 180 percent above baseline and cortisol took a step up of about 40 percent, so this is not a compound that leaves the rest of the hormone system alone. Past that the record is empty rather than clean. The author found no dedicated toxicology programme, and no repeat dose, genetic damage, reproductive or cancer study surfaced in their searches, and unlike ipamorelin there is no regulator's review document recording anybody going looking, so that absence is the author's own search rather than an established fact about the world. The side effect lists on vendor pages, water retention, pins and needles, flushing, hunger and fatigue, the author could not trace to any published human trial. The one signal worth holding onto comes from rat hearts, where the compound narrowed the heart's own blood vessels as the amount rose, and the paper reporting it closes by suggesting the protein behind that may be involved in coronary vessel spasm. On the record elsewhere: the World Anti-Doping Agency names examorelin, which is hexarelin, under section S2.2.4, prohibited at all times, in and out of competition, and non-Specified, the more serious tier. There is no United States Food and Drug Administration approval and a query of the agency's open database for the substance name returns no matches, and the author found no European Medicines Agency record and no approval anywhere else, which the entry says plainly is not the same as establishing that none exists. It is also absent from the compounding lists, which the entry reads as a gap rather than a clearance: not on the Category 2 list of substances that may present significant safety risks, whose 14 entries include GHRP-2, GHRP-6 and ipamorelin acetate, and not on the 503B Bulks List.