Skip to content
Educational information only. Not medical advice. We sell nothing and take no affiliate money.
By /
PeptideLimited humanNot FDA approved

Hexarelin

Hexarelin

Last reviewed October 27, 2026 · 25 sources · Written for general readers · Compare with another compound →

The bottom line

Hexarelin is a lab made peptide that causes a strong burst of growth hormone by acting on the ghrelin receptor. In small human studies its effect faded with steady use, it did not change muscle or fat over 16 weeks, and it raised stress hormones and reduced deep sleep. It briefly made the heart pump harder in tiny studies, and it protected the heart in rats and mice, but it was never approved, it is banned in sport, and products sold online are unregulated.

Where the evidence stands

What it is

Hexarelin is a synthetic peptide made of six building blocks (amino acids).[1] WADA groups it with the growth hormone releasing peptides, drugs that push the pituitary gland to release growth hormone.[2]

FDA's substance registry lists it under the name examorelin, with CAS number 140703-51-1.[3] We found no FDA approval for it as a medicine.

Researchers studied it mostly in the 1990s and early 2000s: as a test of the pituitary, as a possible growth treatment for short children, and for a possible direct effect on the heart.[4][5]

Name
Hexarelin (Hexarelin)
Other names
examorelin
Type
Peptide
CAS number
140703-51-1
Formula
C47H58N12O6
Molecular weight
About 887.0 g/mol

What it does in the body

Hexarelin is not made by the body. It copies the action of ghrelin, the body's hunger hormone, by switching on the growth hormone secretagogue receptor (the ghrelin receptor) in the brain and pituitary gland, which makes the pituitary release a burst of growth hormone.[10] It also binds a second receptor called CD36, found in heart tissue, which may explain heart effects that do not depend on growth hormone.[10][7]

This is the biology, area by area. A change measured in the body, like a higher blood level, does not always mean a person feels a benefit. The claims check below covers that.

Hormones

Measured in people

In healthy volunteers, hexarelin caused a fast rise in growth hormone by vein, shot, nasal spray and, weakly, by mouth, and the rise was about twice that from the body's own releasing hormone, GHRH.[1] The response grew with the amount given until it leveled off.[6] In 6 healthy men, a second dose given two hours after the first produced a smaller peak, while the drop with a one hour gap was not statistically significant.[11] Over 16 weeks of repeated shots, the response fell by about 45 percent and returned 4 weeks after stopping, and IGF-1, the growth factor that growth hormone raises, did not change significantly.[8]

Stress hormones and prolactin

Measured in people

Hexarelin is less selective than the body's own growth hormone signal. In healthy men it raised prolactin, the milk hormone, by up to about 180 percent and cortisol, the main stress hormone, by about 40 percent.[6] During sleep it also raised ACTH, the brain signal that drives cortisol.[12]

Heart and blood vessels

Measured in people

Receptors for hexarelin are found in the heart and blood vessels, not just the brain.[10] In 7 men with growth hormone deficiency and 9 healthy men, one IV dose raised the share of blood pumped with each beat by about 7 points for a short time, even though growth hormone barely rose in the deficient men.[5] In 24 men having bypass surgery, it raised heart output for up to 90 minutes while growth hormone itself did not.[13] These were one time measurements, not proof of lasting benefit.

Heart repair in animals

Seen in animals

In mice given a heart attack, 21 days of hexarelin preserved pumping, reduced scarring and lowered blood markers of heart damage and inflammation.[14][15] In rats with high blood pressure, 5 weeks of treatment reduced scar tissue in the heart, heart thickening and blood pressure, and these effects disappeared when the ghrelin receptor was blocked.[16] In rats without a pituitary gland, it still protected the heart, so this effect does not need growth hormone.[7]

Sleep

Measured in people

In a placebo controlled study of 7 young healthy volunteers, hexarelin given at night reduced the deepest stage of sleep in the first half of the night and lowered deep sleep brain waves through the night.[12]

Fat and blood sugar

Seen in animals

In mouse fat cells, hexarelin acting through CD36 switched on genes for burning fat and building mitochondria, and this effect was lost in mice lacking CD36.[17] In insulin resistant mice, 12 days of shots improved blood sugar handling, lowered blood and liver fats and shifted body makeup toward less fat and more lean mass, though the mice ate more.[18] In people, 16 weeks of shots did not change body fat significantly.[8]

Muscle

Seen in animals

In rats given the cancer drug cisplatin, which wastes muscle, hexarelin protected the mitochondria (the cell's power plants) in leg muscle.[19] In people, lean mass did not change significantly over 16 weeks of shots.[8]

How it works

Hexarelin triggers growth hormone release from the pituitary gland, and it reaches the blood when given by vein, by shot, by nasal spray and, poorly, by mouth.[1]

  • In 12 healthy volunteers, it released about twice as much growth hormone as the same amount of GHRH, the body's own growth hormone releasing hormone, given by vein.[1]
  • A small amount combined with GHRH produced a large growth hormone release with little effect on other hormones, so the two work together.[6]
  • At higher amounts it also raised the stress hormone cortisol and the milk hormone prolactin.[6]
  • It also seems to act on the heart directly. In rats, its heart protection did not depend on growth hormone,[7] and in people whose pituitary could barely make growth hormone, it still made the heart pump harder for a short time.[5]
  • With repeated use, the pituitary responds less, a process called desensitization.[8][9]

The hormone effects are well measured in people. The heart effects are short term in people and longer term only in animals.

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Heart protection and metabolic effects in rats and mice

  • In rats without pituitary glands, a week of hexarelin shots limited heart damage after blood flow was cut off and restored. A related peptide that does not bind the heart had no such effect.[7]
  • In mice given a heart attack, a single dose by mouth improved heart pumping in the following weeks and lowered stress hormones such as epinephrine, though survival over 14 days did not differ.[21]
  • In mice with a heart attack, 21 days of hexarelin (11 treated, 10 untreated) improved pumping at 14 days and reduced heart scar tissue and blood markers of inflammation. A second study in 38 mice whose blocked artery was reopened found similar protection.[14][15]
  • In rats with high blood pressure, 5 weeks of treatment reduced heart scarring, heart thickening, stiffness and blood pressure. Blocking the ghrelin receptor cancelled these effects.[16]
  • In rats with heart failure caused by a narrowed aorta, three weeks of shots of hexarelin or related peptides improved pumping, reduced body wasting, lowered stress hormones and reduced heart cell death.[22]
  • In insulin resistant mice, 12 days of shots improved blood sugar handling and lowered blood and liver fats. In rats treated with cisplatin, it protected muscle mitochondria.[18][19]

Limit: These results are from animals with surgically or chemically induced disease and have not been tested in human trials.

Human studies

Small short studies of hormones, growth and the heart

  • In 12 healthy young volunteers, hexarelin raised growth hormone by IV, shot, nasal spray and pill. Most of a shot reached the blood, but very little of a pill did.[1]
  • In healthy men given IV hexarelin, growth hormone rose with the amount given until it leveled off. Prolactin rose by up to about 180 percent and cortisol by about 40 percent.[6]
  • In 6 healthy men aged 25 to 34, a repeat IV dose given two hours after the first produced a smaller growth hormone peak, while the fall when the gap was one hour was not statistically significant, and the extra boost seen when it was combined with GHRH disappeared with repeat dosing.[11]
  • In a 16 week study of repeated shots under the skin, the growth hormone response fell by about 45 percent and recovered 4 weeks after stopping. IGF-1, body fat, lean mass and bone density did not change significantly, and only one bone building marker rose.[8]
  • In an open study of 8 short children aged 4 to 11, a nasal spray used for up to 8 months raised IGF-1 and growth speed from 5.3 to 8.3 centimeters per year. The authors reported no side effects.[4]
  • In 7 more short children treated for 6 to 10 months, the growth hormone response to a test dose fell by about half within 7 days, yet growth speed still rose from 5.3 to 7.4 centimeters per year. The response partly recovered 3 months after stopping.[9]
  • In a placebo controlled sleep study of 7 young healthy volunteers, hexarelin reduced deep sleep and raised growth hormone, prolactin, ACTH and cortisol during the night. Leptin and immune markers did not change.[12]
  • In 7 men with growth hormone deficiency and 9 healthy men, one IV dose briefly raised heart pumping (ejection fraction) by about 7 points in both groups, even though growth hormone barely rose in the deficient men. Blood pressure and cardiac output did not change.[5]
  • In 13 adults with severe heart failure, one IV dose raised ejection fraction from about 23 to 26 percent in 5 with heart disease from blocked arteries, but not in 8 with dilated heart muscle disease.[20]
  • In 24 men during heart bypass surgery, hexarelin raised ejection fraction and cardiac output and lowered pressure in the lungs' blood vessels for up to 90 minutes. GHRH, growth hormone and placebo had no such effect.[13]
  • A 2026 review of growth hormone boosting peptides used without a prescription, including hexarelin, found no human trials of performance or body shaping benefits and listed raised prolactin and cortisol, appetite changes, blood sugar problems and fluid retention among the reported side effects of this drug group.[23]

Limit: Every study was small and short, most had no placebo group, and none tracked strength, heart attacks, survival or long term safety.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Raises growth hormone

Shown in people

In healthy volunteers, hexarelin caused a strong growth hormone release when given by vein, shot, nasal spray or pill, and the rise grew with the amount given until it leveled off.[1][6] But the effect fades. In a 16 week study of repeated shots, the growth hormone response fell by about 45 percent, then returned to normal 4 weeks after stopping.[8]

Builds muscle

No benefit in trials so far

In the 16 week study of repeated shots, lean mass did not change significantly, and neither did IGF-1, the growth factor that carries out many of growth hormone's effects.[8] The study was small and had no placebo group. No other trial has measured muscle or strength.

Burns fat

No benefit in trials so far

In the same 16 week study, body fat did not change significantly.[8] In short children, skinfold thickness fell during treatment, but there was no comparison group.[4]

Prevents muscle wasting

Only in animals

In rats with muscle wasting caused by the chemotherapy drug cisplatin, hexarelin protected muscle mitochondria from damage.[19] No human study has tested hexarelin for muscle wasting, and in a 16 week study of repeated shots in people, lean mass did not change significantly.[8]

Improves sleep

No benefit in trials so far

In a placebo controlled study of 7 young healthy volunteers, hexarelin given during the night reduced the deepest stage of sleep in the first half of the night and lowered deep sleep brain waves all night. It also raised cortisol and ACTH, two stress hormones.[12]

Makes the heart pump stronger

Mixed results

In 7 men with growth hormone deficiency and 9 healthy men, one IV dose raised the share of blood the heart pumps out with each beat (ejection fraction) from 50 to 57 percent and from 63 to 70 percent, for a short time.[5] In 24 men having heart bypass surgery, it raised ejection fraction and cardiac output within 10 minutes, lasting up to 90 minutes, while GHRH, growth hormone and placebo did not.[13] In 13 people with severe heart failure, it raised ejection fraction in the 5 whose failure came from blocked arteries but not in the 8 with dilated heart muscle disease.[20] No study tested lasting benefit.

Protects the heart after a heart attack

Only in animals

In mice, one dose by mouth after a heart attack improved heart pumping weeks later.[21] In rats with heart failure, three weeks of shots improved pumping and reduced body wasting.[22] No human trial has tested this.

Helps short children grow

Mixed results

In two open studies from one Israeli group, 8 and then 7 short children used a nasal spray for up to 10 months. Growth speed rose from about 5.3 to 8.3 centimeters per year in the first study and to 7.4 in the second.[4][9] Neither study had a control group, and the pituitary's response fell by about half within a week.[9]

Known risks and side effects

  • Raises stress hormones and prolactin. In healthy men, hexarelin raised prolactin by up to about 180 percent and cortisol by about 40 percent.[6] It also raised ACTH and cortisol during sleep.[12]
  • Less deep sleep. In 7 healthy volunteers, it reduced the deepest stage of sleep compared with placebo nights.[12]
  • Effect fades and long term safety is unknown. The growth hormone response dropped by about half with steady use in adults and children, and a second dose given soon after the first gave a smaller response.[8][9][11] No large or long trials exist, and most studies did not report side effects in detail.
  • Side effects seen with this drug group. A 2026 review lists raised prolactin and cortisol, appetite changes, blood sugar problems, fluid retention, muscle and joint aches and injection site reactions as side effects reported with growth hormone boosting peptides.[23]
  • Unregulated products and sport bans. Hexarelin is not an approved drug and is not on FDA's 503A compounding category lists,[24] so vials sold online have unknown purity, strength and sterility. WADA lists examorelin (hexarelin) as a prohibited growth hormone releasing peptide in 2026 and again in its 2027 list.[2][25]

Regulatory status

Today: Hexarelin is not FDA approved for any use, and it does not appear in any category of FDA's 503A compounding nomination list updated May 14, 2026.[24] WADA bans it at all times under the 2026 list, and the 2027 list that takes effect January 1, 2027 still names examorelin (hexarelin).[2][25]

  1. The 2026 WADA Prohibited List took effect and names examorelin (hexarelin).[2]
  2. FDA's updated 503A nomination list does not include hexarelin in any category.[24]
  3. WADA published its 2027 Prohibited List, which again names examorelin (hexarelin) among banned growth hormone releasing peptides.[25]
  4. The 2027 WADA Prohibited List takes effect.[25]

Sources

  1. Ghigo E, Arvat E, Gianotti L, Imbimbo BP, Lenaerts V, Deghenghi R, Camanni F. Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man. J Clin Endocrinol Metab. 1994;78(3):693-698. PMID 8126144
  2. World Anti-Doping Agency. World Anti-Doping Code: 2026 Prohibited List, section S2.2.4 (growth hormone releasing peptides). In force January 1, 2026. WADA 2026
  3. U.S. FDA and NCATS Global Substance Registration System (GSRS). Examorelin (hexarelin), UNII 09QF37C617. FDA GSRS
  4. Laron Z, Frenkel J, Deghenghi R, Anin S, Klinger B, Silbergeld A. Intranasal administration of the GHRP hexarelin accelerates growth in short children. Clin Endocrinol (Oxf). 1995;43(5):631-635. PMID 8548949
  5. Bisi G, Podio V, Valetto MR, Broglio F, Bertuccio G, Aimaretti G, et al. Cardiac effects of hexarelin in hypopituitary adults. Eur J Pharmacol. 1999;381(1):31-38. PMID 10528131
  6. Massoud AF, Hindmarsh PC, Brook CG. Hexarelin-induced growth hormone, cortisol, and prolactin release: a dose-response study. J Clin Endocrinol Metab. 1996;81(12):4338-4341. PMID 8954038
  7. Locatelli V, Rossoni G, Schweiger F, Torsello A, De Gennaro Colonna V, Bernareggi M, Deghenghi R, Müller EE, Berti F. Growth hormone-independent cardioprotective effects of hexarelin in the rat. Endocrinology. 1999;140(9):4024-4031. PMID 10465272
  8. Rahim A, O'Neill PA, Shalet SM. Growth hormone status during long-term hexarelin therapy. J Clin Endocrinol Metab. 1998;83(5):1644-1649. PMID 9589671
  9. Klinger B, Silbergeld A, Deghenghi R, Frenkel J, Laron Z. Desensitization from long-term intranasal treatment with hexarelin does not interfere with the biological effects of this growth hormone-releasing peptide in short children. Eur J Endocrinol. 1996;134(6):716-719. PMID 8766941
  10. Mao Y, Tokudome T, Kishimoto I. The cardiovascular action of hexarelin. J Geriatr Cardiol. 2014;11(3):253-258. PMID 25278975
  11. Massoud AF, Hindmarsh PC, Matthews DR, Brook CG. The effect of repeated administration of hexarelin, a growth hormone releasing peptide, and growth hormone releasing hormone on growth hormone responsivity. Clin Endocrinol (Oxf). 1996;44(5):555-562. PMID 8762732
  12. Frieboes RM, Antonijevic IA, Held K, Murck H, Pollmächer T, Uhr M, Steiger A. Hexarelin decreases slow-wave sleep and stimulates the secretion of GH, ACTH, cortisol and prolactin during sleep in healthy volunteers. Psychoneuroendocrinology. 2004;29(7):851-860. PMID 15177700
  13. Broglio F, Guarracino F, Benso A, Gottero C, Prodam F, Granata R, et al. Effects of acute hexarelin administration on cardiac performance in patients with coronary artery disease during by-pass surgery. Eur J Pharmacol. 2002;448(2-3):193-200. PMID 12144941
  14. McDonald H, Peart JN, Kurniawan ND, Galloway GJ, Royce SG, Samuel CS, Chen C. Hexarelin treatment preserves myocardial function and reduces cardiac fibrosis in a mouse model of acute myocardial infarction. Physiol Rep. 2018;6(9):e13699. PMID 29756411
  15. McDonald H, Peart JN, Kurniawan ND, Galloway G, Royce SG, Samuel CS, Chen C. Hexarelin targets neuroinflammatory pathways to preserve cardiac morphology and function in a mouse model of myocardial ischemia-reperfusion. Biomed Pharmacother. 2020;127:110165. PMID 32403043
  16. Xu X, Ding F, Pang J, Gao XJ, Xu RK, Hao W, Cao JM, Chen C. Chronic administration of hexarelin attenuates cardiac fibrosis in the spontaneously hypertensive rat. Am J Physiol Heart Circ Physiol. 2012;303(6):H703-H711. PMID 22842067
  17. Rodrigue-Way A, Demers A, Ong H, Tremblay A. A growth hormone-releasing peptide promotes mitochondrial biogenesis and a fat burning-like phenotype through scavenger receptor CD36 in white adipocytes. Endocrinology. 2007;148(3):1009-1018. PMID 17138655
  18. Mosa R, Huang L, Wu Y, Fung C, Mallawakankanamalage O, LeRoith D, Chen C. Hexarelin, a Growth Hormone Secretagogue, Improves Lipid Metabolic Aberrations in Nonobese Insulin-Resistant Male MKR Mice. Endocrinology. 2017;158(10):3174-3187. PMID 28977588
  19. Sirago G, Conte E, Fracasso F, Cormio A, Fehrentz JA, Martinez J, et al. Growth hormone secretagogues hexarelin and JMV2894 protect skeletal muscle from mitochondrial damages in a rat model of cisplatin-induced cachexia. Sci Rep. 2017;7(1):13017. PMID 29026190
  20. Imazio M, Bobbio M, Broglio F, Benso A, Podio V, Valetto MR, Bisi G, Ghigo E, Trevi GP. GH-independent cardiotropic activities of hexarelin in patients with severe left ventricular dysfunction due to dilated and ischemic cardiomyopathy. Eur J Heart Fail. 2002;4(2):185-191. PMID 11959048
  21. Mao Y, Tokudome T, Kishimoto I, Otani K, Miyazato M, Kangawa K. One dose of oral hexarelin protects chronic cardiac function after myocardial infarction. Peptides. 2014;56:156-162. PMID 24747279
  22. Xu XB, Pang JJ, Cao JM, Ni C, Xu RK, Peng XZ, et al. GH-releasing peptides improve cardiac dysfunction and cachexia and suppress stress-related hormones and cardiomyocyte apoptosis in rats with heart failure. Am J Physiol Heart Circ Physiol. 2005;289(4):H1643-H1651. PMID 15951341
  23. Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026;17:1822475. PMID 42395176
  24. U.S. Food and Drug Administration. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act. Updated May 14, 2026. FDA 503A categories
  25. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2027, sections S2 and S4.3. Published September 2026; in force January 1, 2027. WADA 2027
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

Found an error or a newer study? We correct pages fast.

Report a correction →
Scroll to Top