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Hexarelin

Hexarelin is a synthetic six-amino-acid growth hormone-releasing peptide (GHRP) that acts on the ghrelin receptor. In human studies from the 1990s and 2000s it was among the most potent GH releasers in its class, but its effect weakened with repeated use and it also raised cortisol and prolactin. It was never approved as a medicine.

By the PepFinder editorial team · Reviewed 23 Sept 2026 · Editorial independence

Hexarelin suppliers and prices

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28 suppliers in our directory list Hexarelin. Median price per mg: US$9.26 (11 suppliers pricing in USD), £6.00 (7 suppliers pricing in GBP), CA$10.80 (3 suppliers pricing in CAD), A$18.00 (1 supplier pricing in AUD). Prices are compared only within the same currency.

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What it is

Hexarelin is a synthetic hexapeptide from the same family as GHRP-6, to which it is structurally very close, and GHRP-2. It was developed in the early 1990s and studied extensively by endocrinologists at the University of Turin, whose 1994 paper showed that it released GH in healthy volunteers by intravenous, subcutaneous, nasal and oral routes [1].

Like other GHRPs, hexarelin mimics ghrelin at the growth hormone secretagogue receptor. It differs from ipamorelin, a later and more selective member of the family, in that it also stimulates ACTH, cortisol and prolactin.

How it is thought to work

Hexarelin binds the GHS-R1a (ghrelin) receptor on the pituitary and hypothalamus and triggers GH release. In young men, the maximally effective dose of hexarelin released more GH than the maximally effective dose of GHRH, and giving the two together amplified the response further [2]. The GH response was clearly smaller in men aged 65 to 84 than in young men [2].

Hexarelin also appears to have effects on the heart that do not depend on GH. In patients undergoing heart bypass surgery, it improved cardiac performance, while GHRH and recombinant GH given for comparison did not, suggesting a direct action on receptors in heart or blood-vessel tissue [3].

What the research shows

In healthy young volunteers, hexarelin produced dose-dependent GH release. An intravenous dose of 1 µg/kg released about twice as much GH as the same dose of GHRH. Bioavailability relative to intravenous dosing was about 77% under the skin, 5% by nasal spray and 0.3% by mouth [1].

Repeated dosing blunts the response. In a Manchester study, 12 healthy older adults injected hexarelin twice daily for 16 weeks. The GH response fell significantly by week 4 and was about 45% lower than baseline by week 16; four weeks after stopping it had returned to baseline. The authors concluded the attenuation was partial and reversible [4]. In the same regimen, the cortisol response was modestly but significantly lower after 16 weeks, prolactin responses did not change, and there was no change in 24-hour urinary cortisol [5].

In healthy young men given two or three daily injections for one day, 24-hour GH secretion rose through larger pulses, not more frequent ones. A test dose given afterwards produced a smaller GH response, while its ACTH and cortisol responses were abolished [6]. Given at night, hexarelin reduced deep (stage 4) sleep and raised GH, prolactin, ACTH and cortisol in seven healthy volunteers [7].

Research: heart

Hexarelin’s possible cardiac effects became a major focus of later research. In 13 patients with severe left ventricular dysfunction, a single intravenous dose increased ejection fraction in those with ischaemic cardiomyopathy but not in those with dilated cardiomyopathy [8]. During bypass surgery, a single 2 µg/kg dose raised ejection fraction, cardiac index and cardiac output within 10 minutes, lasting up to 90 minutes [3]. Both were small, acute studies.

Most of the rest of the cardiac evidence is from animals. In mice with an experimental heart attack, 0.3 mg/kg per day for 21 days preserved left ventricular function and reduced fibrosis compared with vehicle [9]. There are no long-term human trials of hexarelin for heart disease.

Doses used in published research

Human studies used single intravenous doses of 1 or 2 µg/kg, subcutaneous doses of 1.5 or 3 µg/kg, 20 µg/kg nasally and 20 or 40 mg by mouth [1][2][3]. Repeated-dosing studies used 1.5 µg/kg under the skin twice daily for 16 weeks [5] or two to three times in one day [6], and the sleep study gave four 50 µg intravenous doses an hour apart [7]. The mouse heart study used 0.3 mg/kg per day [9]. These are the doses researchers used, not recommendations; animal doses should not be converted to human ones.

Safety and side effects reported

The published studies were short and small, and their abstracts focus on hormone responses rather than side effects. The effects that are documented are hormonal: acute rises in ACTH, cortisol and prolactin with single doses [6][7], loss of GH response with continued use [4], and reduced deep sleep when given at night [7]. Long-term safety has not been studied. Research-grade products are not made to medicine standards.

Regulatory status

Hexarelin is not an approved medicine in the UK, US, Canada, Australia or New Zealand. It is listed by WADA as examorelin (hexarelin) among the GH-releasing peptides in section S2 and is banned at all times [10]. For the rules on buying research peptides in each country, see our legal status overview.

Storage and handling

Research-grade hexarelin is supplied as freeze-dried powder with no published stability data. See our guides to storing peptides and bacteriostatic water for general practice.

Buying and testing

Compare prices, check the COA with our guide on how to read a COA, and prefer third-party tested suppliers.

References

  1. [1] Ghigo E, Arvat E, Gianotti L, Imbimbo BP, et al. Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man J Clin Endocrinol Metab. 1994. PubMed 8126144
  2. [2] Arvat E, Gianotti L, Grottoli S, Imbimbo BP, et al. Arginine and growth hormone-releasing hormone restore the blunted growth hormone-releasing activity of hexarelin in elderly subjects J Clin Endocrinol Metab. 1994. PubMed 7962341
  3. [3] Broglio F, Guarracino F, Benso A, Gottero C, et al. Effects of acute hexarelin administration on cardiac performance in patients with coronary artery disease during by-pass surgery Eur J Pharmacol. 2002. PubMed 12144941
  4. [4] Rahim A, Shalet SM Does desensitization to hexarelin occur? Growth Horm IGF Res. 1998. PubMed 10990150
  5. [5] Rahim A, O'Neill PA, Shalet SM The effect of chronic hexarelin administration on the pituitary-adrenal axis and prolactin Clin Endocrinol (Oxf). 1999. PubMed 10341859
  6. [6] Maccario M, Veldhuis JD, Broglio F, Di Vito L, et al. Impact of two or three daily subcutaneous injections of hexarelin, a synthetic growth hormone (GH) secretagogue, on 24-h GH, prolactin, adrenocorticotropin and cortisol secretion in humans Eur J Endocrinol. 2002. PubMed 11888836
  7. [7] Frieboes RM, Antonijevic IA, Held K, Murck H, et al. Hexarelin decreases slow-wave sleep and stimulates the secretion of GH, ACTH, cortisol and prolactin during sleep in healthy volunteers Psychoneuroendocrinology. 2004. PubMed 15177700
  8. [8] Imazio M, Bobbio M, Broglio F, Benso A, et al. GH-independent cardiotropic activities of hexarelin in patients with severe left ventricular dysfunction due to dilated and ischemic cardiomyopathy Eur J Heart Fail. 2002. PubMed 11959048
  9. [9] McDonald H, Peart J, Kurniawan N, Galloway G, et al. Hexarelin treatment preserves myocardial function and reduces cardiac fibrosis in a mouse model of acute myocardial infarction Physiol Rep. 2018. PubMed 29756411
  10. [10] World Anti-Doping Agency The Prohibited List (2026): S2.2.4 Growth hormone releasing factors wada-ama.org. 2026. Source

Frequently asked questions

What is hexarelin?

Hexarelin is a synthetic six-amino-acid peptide that stimulates growth hormone release through the ghrelin receptor. It belongs to the GHRP family alongside GHRP-2 and GHRP-6.

Does hexarelin stop working over time?

In a 16-week study in older adults, the GH response to twice-daily hexarelin fell by about 45%, but it recovered within four weeks of stopping. The authors described the attenuation as partial and reversible.

Does hexarelin raise cortisol?

Single doses of hexarelin raised ACTH, cortisol and prolactin in human studies. With 16 weeks of twice-daily use, cortisol responses did not increase and prolactin responses were unchanged.

What is hexarelin’s link to the heart?

In small studies, a single intravenous dose improved heart pumping in some patients with heart disease, an effect GHRH and GH did not share. Longer-term evidence comes only from animal studies.

Is hexarelin banned in sport?

Yes. WADA lists examorelin (hexarelin) among the GH-releasing peptides that are prohibited at all times.

Related

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