Hexarelin: What It Is, Where to Get It Prescribed, and What It Costs

Hexarelin is a hexapeptide — six amino acids, sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2. Two of the six are unnatural D-amino acids and one carries a methyl group not found in any natural protein, which is what lets it survive in the body long enough to act. It is entirely synthetic. What it imitates is ghrelin, the stomach hormone that signals hunger and tells the pituitary to release growth hormone.

It is not growth hormone and contains none. It is a signal to the pituitary, and the pituitary decides how much to release: a secretagogue can only ask for what the gland is still able to give. In the 1995 paediatric work in the Journal of Clinical Endocrinology and Metabolism, children with organic hypopituitarism released no growth hormone at all in response to it, because there was nothing to stimulate.

Hexarelin was designed in the early 1990s by a European research group as an analogue of GHRP-6, the first of the growth hormone-releasing peptides; the papers of the period call it a "super-analogue," meaning a version built to be more stable and more potent than the parent. The founding human study, in the Journal of Clinical Endocrinology and Metabolism in 1994, gave it to twelve healthy young volunteers by four routes and reported that a single intravenous dose released about twice as much growth hormone as the same dose of GHRH, that the subcutaneous route delivered 77 per cent of the intravenous response, and that intranasal and oral doses released growth hormone too but with far lower bioavailability.

Through the rest of the 1990s the University of Turin and other groups used it as a research tool in hundreds of adults and children, mostly to probe how the growth hormone axis works and whether it could serve as a diagnostic test for growth hormone deficiency. That is why hexarelin has more human pharmacology on record than almost any other compounded peptide, and also why almost none of it concerns the way it is prescribed today.

It is not an anabolic steroid; it does not bind the androgen receptor or suppress testosterone. It is not selective in the way ipamorelin is: a dose of hexarelin releases growth hormone and, in the same hour, a smaller pulse of prolactin, ACTH and cortisol. And it is not a heart medication — the cardiac work below is research, and no regulator has approved it as a treatment for anything.

Hexarelin binds the growth hormone secretagogue receptor, GHS-R1a, the receptor ghrelin uses, and triggers a pulse of growth hormone from the pituitary rather than a sustained rise. In the 1994 volunteer study the response to an intravenous dose was dose-dependent and highly reproducible. A 2001 comparison in the Journal of Clinical Endocrinology and Metabolism gave healthy young men ghrelin, hexarelin and GHRH on separate days: ghrelin released the most growth hormone, hexarelin the next most, GHRH the least, and hexarelin and ghrelin did not add to each other, which is what you expect from two ligands for the same receptor.

The pituitary listens to two inputs: GHRH from the hypothalamus and ghrelin-type signals from the gut. They act on different receptors, and in a 1996 study in Clinical Endocrinology giving hexarelin together with GHRH produced a peak growth hormone secretion rate greater than the sum of the two alone. The same study found that a second dose two hours later produced a smaller peak, and that the synergy was lost on repeat dosing. That is the logic behind pairing a ghrelin-type peptide with a GHRH analogue, and it is also the first appearance in the human literature of the desensitisation theme that runs through everything else on this page.

Unlike the later, selective secretagogues, hexarelin also stimulates the pituitary cells that make ACTH and prolactin. A 1997 study in Peptides compared hexarelin and GHRP-2 in young adults and reported that both raised prolactin, ACTH and cortisol; the ACTH and cortisol response was similar in size to that from corticotropin-releasing hormone, while the prolactin response was smaller than that from TRH. The 1997 work in the Journal of Clinical Endocrinology and Metabolism characterised the ACTH- and cortisol-releasing effect in normal subjects and in Cushing's patients. This is the pharmacological reason hexarelin is described as "stronger" and "less clean" in the same breath.

Ghrelin receptors sit on heart muscle and blood vessels as well as in the pituitary, and hexarelin also binds a second, unrelated receptor called CD36 that is expressed on cardiomyocytes. A 2002 paper in Circulation Research reported that CD36 mediates the cardiovascular action of growth hormone-releasing peptides in the isolated heart. Together these are the proposed basis for the cardiac effects described below being independent of growth hormone: in the rat work, a GHRP that does not bind the heart had no cardiac effect, and in humans recombinant growth hormone itself did not reproduce hexarelin's effect on ejection fraction.

A 2008 review in PPAR Research described hexarelin binding CD36 on macrophages and activating PPARγ, a nuclear receptor involved in lipid handling, and a 2017 paper in Endocrinology reported that hexarelin improved lipid metabolic abnormalities in a non-obese insulin-resistant mouse. This is cell and mouse work, and it does not describe fat loss in people; it is the mechanistic thread behind the older rat work in obese Zucker rats and against atherosclerosis in a cholesterol-fed model.

This is the most solidly established finding, replicated across dozens of studies from 1994 onward. In healthy young adults a single dose reliably produces a large growth hormone pulse, larger than GHRH, by every route tested. The response is smaller in older adults — a 1994 paper reported it blunted in the elderly and restored by arginine or GHRH, and a 1997 paper in the European Journal of Endocrinology described the growth hormone, prolactin, ACTH and cortisol responses each changing differently with age. It is also blunted in obesity, and a 2000 paper in Hormone and Metabolic Research described food intake modulating the response. A 2002 study in the European Journal of Endocrinology gave six young men two or three subcutaneous injections across a day and reported that either schedule raised 24-hour growth hormone secretion by enlarging each pulse without changing pulse frequency, and did not alter 24-hour prolactin, ACTH or cortisol.

Much of the 1990s literature examines hexarelin as a stimulation test. A 1999 study in the Journal of Clinical Endocrinology and Metabolism compared low-dose hexarelin plus GHRH against the insulin tolerance test in adults with suspected growth hormone deficiency, and a 1999 paper in Clinical Endocrinology examined it as a test of pituitary reserve in patients with pituitary disease. Patients with a defective GHRH receptor were reported to show a selective lack of response. This is diagnostic pharmacology, not treatment, but it is the reason the human safety record of single doses is unusually deep.

Two small open-label studies from the same Israeli group are the only sustained treatment courses in the literature. In Clinical Endocrinology in 1995, eight prepubertal short children were given intranasal hexarelin three times daily for up to eight months; IGF-1 rose and mean growth velocity was reported to increase from 5.3 to 8.3 cm per year, with a fall in skinfold thickness. The 1996 companion paper in the European Journal of Endocrinology, in seven children treated for six to ten months, reported that the growth hormone response to a test dose fell by about half within seven days and stayed at that level for the rest of treatment, recovering partly three months after stopping — while growth velocity still increased, from 5.3 to 7.4 cm per year. Eight and seven children, no control group, intranasal route, 30 years ago: those are the limits.

The single most important paper for anyone considering a course is in the Journal of Clinical Endocrinology and Metabolism in 1998. Healthy elderly volunteers were given twice-daily subcutaneous hexarelin for sixteen weeks. The growth hormone response to a test dose fell steadily: the area under the curve dropped by about a third by week one, by more than a third by week four, and by nearly half by week sixteen. Four weeks after stopping, the response had returned to baseline. Over the same sixteen weeks, IGF-1, IGF-binding protein 3, total body fat, lean body mass and bone mineral density did not change significantly; one marker of collagen formation rose. The authors' summary was that chronic hexarelin produces "a partial and reversible attenuation of the GH response" and that the biological impact of that schedule on the growth hormone–IGF-1 axis "seems to be minimal."

Two shorter studies in older adults, in the European Journal of Endocrinology in 1996, used intermittent intranasal or oral dosing for eight and fifteen days and found no desensitisation, with a small rise in IGF-binding protein 3 and, on the oral schedule, in IGF-1. And a 2003 paper in the Journal of Endocrinological Investigation reported rapid desensitisation of the ghrelin receptor to hexarelin in cell culture. The picture across all of it is consistent: continuous exposure turns the receptor down, the turn-down is partial and reverses within weeks of stopping, and it is much less pronounced with intermittent dosing. That is the entire rationale for the five-nights-on, two-off schedule.

Three small studies from Turin, all single intravenous doses, all measuring the heart directly. In the Journal of Endocrinological Investigation in 1999, seven male volunteers had left ventricular ejection fraction measured by radionuclide angiography after hexarelin and, separately, after recombinant growth hormone; hexarelin raised ejection fraction from 64 to about 71 per cent for roughly an hour, with no change in blood pressure or heart rate, and growth hormone did not. In the European Journal of Pharmacology in 2002, twenty-four men with coronary artery disease received hexarelin, GHRH, growth hormone or placebo during bypass surgery under anaesthesia; only hexarelin produced a rise in ejection fraction, cardiac index and cardiac output from ten minutes to ninety minutes, with a fall in wedge pressure and no change in systemic vascular resistance. In the European Journal of Heart Failure in 2002, a dose raised ejection fraction in five patients with ischaemic cardiomyopathy but not in eight with dilated cardiomyopathy, despite the same growth hormone release in both.

Read those for what they are: a short-lived, growth hormone-independent inotropic effect of a single intravenous dose. None of them dosed anyone for more than one session, none used the subcutaneous route, and none measured a clinical outcome.

The animal literature is larger and runs from 1997 to the present. In Endocrinology in 1999, seven days of subcutaneous hexarelin in rats whose pituitaries had been removed prevented the worsening of ischaemia-reperfusion injury that hypophysectomy causes, and a related peptide that does not bind heart tissue did not, which is the origin of the "growth hormone-independent" description. A 2000 paper in Endocrinology reported improved cardiac function in rats after experimental myocardial infarction. Rat and mouse work through the 2000s and 2010s in the American Journal of Physiology – Heart and Circulatory Physiology, Endocrinology and Physiological Reports describes reduced cardiac fibroblast proliferation and collagen synthesis, attenuated fibrosis in spontaneously hypertensive rats, preserved myocardial function and reduced fibrosis after infarction in mice, and protection of cultured cardiomyocytes from angiotensin II- and doxorubicin-induced death. A 2014 review in the Journal of Geriatric Cardiology gathers it. All of it is preclinical.

A 2000 paper in the Journal of Endocrinology reported endocrine, metabolic and cardioprotective effects in obese Zucker rats, a 2010 paper in Peptides described suppression of diet-induced atherosclerosis in rats, and the 2017 mouse work above described improved lipid handling in an insulin-resistant model. There is no human study of hexarelin on body composition that found a change; the one that measured it, the sixteen-week study, found none.

Stated precisely: hexarelin has a large body of human pharmacology — single-dose studies in hundreds of healthy adults, elderly subjects, children and patients with pituitary, adrenal and cardiac disease, almost all from 1994 to 2003 — plus two small open-label paediatric treatment courses of up to eight months, one sixteen-week subcutaneous study in healthy elderly adults, and three single-dose cardiac studies. There are no randomised controlled trials of hexarelin for sleep, recovery, body composition, ageing or any wellness use, and the only sustained subcutaneous course ever published measured body composition and found no change. No pharmaceutical development programme has taken it forward, so there is no phase 2 or phase 3 data of the kind that exists for tesamorelin or the GLP-1 medications.

That is a more substantial human record than most compounded peptides have, and it is what makes the pharmacology on this page reliable. It is not evidence that the use it is prescribed for works, and any source telling you otherwise is overselling it.

• It does not establish that nightly subcutaneous hexarelin changes body composition, recovery or sleep in adults. The one study that measured body composition over sixteen weeks found no change, and no study has measured sleep or recovery.
• It does not establish any cardiac benefit from ongoing subcutaneous use in people. The human cardiac data are single intravenous doses; the sustained data are in rodents.
• It does not establish long-term safety. The longest adult exposure on record is sixteen weeks, in a small study.
• It does not establish efficacy for any condition as an approved treatment. It is not approved for anything.

The pharmacology says what happens on night one: a growth hormone pulse within the hour, with a smaller and shorter rise in cortisol and prolactin alongside it, gone by morning. What people report early is mostly about sleep depth and a feeling of warmth, flushing or hunger shortly after the injection. Some report nothing. None of this signals whether the course is working.

This is where the desensitisation data matter. The sixteen-week study saw the growth hormone response to each dose fall by about a third within the first week of twice-daily dosing and then decline more slowly. The reviewed schedule — one dose a night, five nights a week — is designed to stay closer to the intermittent regimens that did not show desensitisation than to the continuous one that did. Prescribers describe the early sleep reports settling into a steady state in this window rather than building.

If a secretagogue is going to change anything measurable, prescribers describe it as the second or third refill rather than the first, which is why some physicians want a baseline IGF-1 to compare against even though bloodwork is not routinely required for this medication. Reports in this period concern recovery and body composition, and they are reports: the only adult study that measured body composition on hexarelin found no change.

There is no withdrawal and no rebound described in the literature. Because hexarelin asks the pituitary for a pulse rather than replacing growth hormone, the gland's own output is not suppressed, and the human data show the receptor's responsiveness returning to baseline within four weeks of stopping. Some prescribers build that recovery into a course deliberately.

The directions are written in millilitres and insulin-syringe units because that is what you can read off the barrel. 0.25 mL is 25 units on a U-100 syringe. You are not calculating anything — the number is printed on your medication.

Subcutaneous means into the fat layer, not the muscle; the 1994 volunteer work established that this route delivers most of the intravenous response. Abdomen and thigh are the usual sites, rotated. Bedtime lands the pulse on top of the natural nocturnal release rather than after a meal, and food intake was reported in 2000 to modulate the response. Monday through Friday with weekends off is the reviewed schedule; the two nights off are the practical answer to the desensitisation data, because intermittent exposure was the pattern that kept the receptor responsive. Your directions will say.

20 doses at five nights a week is four weeks, which is why refills run on a 28-day cycle. One vial per fill, always — not a stockpile.

Refrigerated, and it ships that way in insulated packaging with ice packs. Beyond-use dating runs from first puncture and is on the label.

Same receptor, different generation. Hexarelin is the older, more potent, less selective compound: in the head-to-head literature it releases more growth hormone per dose than the later peptides, and it releases cortisol and prolactin with it. Ipamorelin was designed to keep the growth hormone pulse and drop the rest. Hexarelin is a physician's choice when a stronger pulse is the priority and the course is structured with breaks; ipamorelin is the default for longer courses.

Different receptors, same gland. Sermorelin and tesamorelin supply the GHRH signal and have controlled human trial data and regulatory history hexarelin lacks; hexarelin supplies the ghrelin signal and, in the human data, produced a larger single-dose response than GHRH. Because the two signals are additive, they are more often combined than chosen between.

The combination pairs a GHRH analogue with the selective GHRP in one vial. Prescribers who want the additive effect and a course that runs uninterrupted start with CJC-1295 / Ipamorelin; those who want the strongest single-agent ghrelin-receptor pulse, and are prepared to schedule around desensitisation, consider hexarelin. Neither has human trial evidence for the uses either is prescribed for.