Hexarelin: Potent GH Secretagogue - Evidence, Dosage, Downsides

Key takeaways

Hexarelin is a synthetic six-amino-acid growth hormone-releasing peptide (GHRP) from the early 1990s. It activates the ghrelin receptor, the same target as ipamorelin, and also binds a second receptor in the heart, CD36. It is not growth hormone, and it has never been an approved drug.
It is a potent growth hormone (GH) releaser in people: 1 to 2 mcg/kg intravenously (about 70 to 140 mcg for a 70 kg adult) produced a near-maximal GH pulse, about twice the response to the same dose of GHRH. The same doses raise prolactin and cortisol.
The effect fades with regular use. In healthy older adults injecting 1.5 mcg/kg twice daily for 16 weeks, the GH response fell by about 45%, while IGF-1, body fat, lean mass and bone density did not change. The response recovered within four weeks of stopping.
Seller charts of 100 to 200 mcg once or twice a day sit close to the doses that were studied. The gap is not the dose but the outcome: no study shows a benefit in adults for muscle, fat, recovery or long-term heart health, and at night it reduced deep sleep.
No US pharmacy may compound hexarelin in October 2026. It fails all three tests in section 503A and appears in none of FDA's compounding categories. It is absent from the Category 2 safety list only because it has never been through FDA's review.

Hexarelin at a glance

Also called: examorelin (international name), HEX, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2
Class: Synthetic growth hormone-releasing peptide (GHRP): a six-amino-acid ghrelin-receptor (GHS-R1a) agonist that also binds the cardiac receptor CD36
Route: Studied intravenously, under the skin, in the nose and by mouth; sold as research vials for injection under the skin
FDA status: Never FDA-approved and never part of an approved drug. Not on the 503A bulks list, in none of FDA's 503A categories (list updated May 14, 2026) and not on FDA's Category 2 page. Not legally compoundable as of October 2026.
FDA Category 2 (compounding restricted): No
Available by prescription (US): No legal US source: no 503A pharmacy or 503B outsourcing facility may compound it; sold only as research-use vials
Best-studied use: 1990s hormone studies in healthy adults, older adults and short children; testing of pituitary GH reserve; single-dose heart studies
Typical monthly cost (telehealth, 2026): No legitimate price, because no legal product exists; the prescribable secretagogue, sermorelin, runs $150 to $400 a month

What hexarelin is and how it works

Hexarelin, international name examorelin, is a six-amino-acid synthetic peptide, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 (Imbimbo 1994). It belongs to the family of growth hormone-releasing peptides (GHRPs) that began with GHRP-6, and its first human dose-response study came from the medical department of Mediolanum Farmaceutici, the Italian company developing it. Most of the human research that followed was done by endocrinology groups in Turin, Manchester, London and Tel Aviv between 1994 and 2004. If peptides are new to you, start with what peptides are.

It works on two receptors.

The ghrelin receptor (GHS-R1a) on the pituitary and hypothalamus. This is the same receptor ghrelin, ipamorelin, GHRP-2, GHRP-6 and the oral drug MK-677 act on. It is a different pathway from growth hormone-releasing hormone (GHRH), the target of sermorelin, which is why a low dose of hexarelin given with GHRH acted synergistically, releasing a large GH pulse without raising cortisol (Massoud 1996).
CD36, a scavenger receptor on heart muscle cells and small blood vessels. Researchers in Montreal identified it as hexarelin's binding protein in rat hearts. In isolated perfused hearts, hexarelin raised coronary perfusion pressure, meaning the coronary vessels narrowed, in a dose-dependent way, and the effect was absent in hearts from mice lacking CD36 (Bodart 2002). The heart claims made for hexarelin trace back to this receptor.

After an intravenous dose, GH peaks at about 30 minutes and returns to baseline within four hours (Imbimbo 1994). The response depends on age: older men released less than half as much GH as young men after the same 2 mcg/kg dose (Arvat 1994). And unlike most peptides, hexarelin works, inefficiently, through the nose and by mouth as well as by injection (Ghigo 1994).

What the evidence actually shows

Hexarelin has more human data than most peptides sold as research chemicals: dozens of small studies from the 1990s. Almost all of them measured hormones after a single dose. Here is how the marketed claims hold up.

Hexarelin claims, graded by the evidence behind them
Claim	Grade	What the evidence shows	Sources
Releases growth hormone in healthy adults	B	In 12 healthy men (double-blind, placebo-controlled, rising doses), single intravenous doses of 0.5, 1 and 2 mcg/kg raised peak GH to 26.9, 52.3 and 55.0 ng/mL versus 3.9 on placebo; 2 mcg/kg was close to the maximum. In 12 young volunteers, 1 mcg/kg released about twice as much GH as the same dose of GHRH.	Imbimbo 1994; Ghigo 1994
Works without an injection	B	GH rose after doses under the skin, in the nose and by mouth. Estimated bioavailability was 77% under the skin, 4.8% nasal and 0.3% oral, so oral doses had to be 20 to 40 mg.	Ghigo 1994
Raises only growth hormone	B	No. In healthy men, intravenous doses raised prolactin by up to 180% and cortisol by about 40% from 0.5 mcg/kg upward. At night, four 50 mcg doses raised GH, prolactin, ACTH and cortisol.	Massoud 1996; Frieboes 2004
Keeps working with regular use	B	Partly. In 12 healthy older adults on 1.5 mcg/kg under the skin twice daily, the GH response to a test dose was lower from week 1, significantly so by week 4, and 45% lower at 16 weeks, then back to baseline four weeks after stopping. In 7 short children on nasal hexarelin, the response halved within a week and stayed low for six months.	Rahim 1998; Rahim and Shalet 1998; Klinger 1996
Raises IGF-1, builds muscle or reduces fat in adults	B	Not shown. In the 16-week study, IGF-1, IGF binding protein-3, total body fat, lean body mass and bone density did not change significantly. No adult study has measured strength or performance.	Rahim 1998
Restores youthful GH output in older adults	B	Older men aged 65 to 84 released less than half as much GH as men aged 24 to 30 after 2 mcg/kg intravenously; adding arginine restored their response. No study has measured an aging outcome.	Arvat 1994
Speeds growth in short children	B	In 7 prepubertal short children, nasal hexarelin 60 mcg/kg three times daily for 6 to 10 months raised growth velocity from 5.3 to 7.4 cm a year despite the fading GH response. Small and uncontrolled; never developed into an approved treatment.	Klinger 1996
Strengthens the heart's pumping	C	One intravenous dose of 2 mcg/kg raised ejection fraction, cardiac index and cardiac output within 10 minutes, lasting up to 90 minutes, in men with coronary disease during bypass surgery; GHRH, growth hormone and placebo did not. In severe heart failure it raised ejection fraction in ischemic but not dilated cardiomyopathy. Single doses only.	Broglio 2002; Imazio 2002
Protects the heart over time	D	Animal and cell data only. In rat and mouse hearts the receptor is CD36, through which hexarelin also narrowed coronary vessels in isolated hearts.	Bodart 2002
Improves sleep	B	No. In 7 young healthy volunteers, four 50 mcg doses given hourly from 10 p.m. reduced stage 4 (deepest) sleep in the first half of the night and deep-sleep EEG power across the night, compared with placebo.	Frieboes 2004

A = strong human trials or meta-analyses · B = small or short human trials · C = observational, mechanistic or indirect human data · D = animal/in-vitro only, or no evidence. Grades describe the evidence, not whether we recommend the use.

Three things stand out.

It is potent, and potency is not the problem. Hexarelin reliably produces a large GH pulse at microgram doses. What it has never done in an adult study is turn that pulse into a higher IGF-1, a change in body composition or any clinical benefit (Rahim 1998).

It is not a clean GH signal. The same doses that release GH raise prolactin and cortisol (Massoud 1996), and given at night they made sleep shallower rather than deeper (Frieboes 2004). That is the main pharmacological difference between hexarelin and ipamorelin, which was selected because it did not raise cortisol in animals.

The body adapts. Regular dosing blunted the GH response within weeks in older adults and within a week in children (Rahim and Shalet 1998) (Klinger 1996). The blunting was partial and reversible, which is the honest version of the "cycling" advice that circulates online.

What you are promised versus what is documented

Online hexarelin pages describe it as the "strongest GHRP" and list lean muscle, fat loss, faster recovery, tendon and joint repair, heart protection and anti-aging. The evidence sorts those into four bins.

Documented in humans: a large, short GH pulse after injection, nasal or oral dosing; rises in prolactin, ACTH and cortisol; a short-lived increase in the heart's pumping after one intravenous dose; faster growth in a handful of short children.
Tested and not found: higher IGF-1, more lean mass, less fat or denser bone after 16 weeks of twice-daily injections in older adults; better sleep.
Never tested in humans: muscle or strength in young adults, fat loss, recovery, tendon or joint healing, long-term heart protection, longevity.
Contradicted by the data: "pure GH release" (cortisol and prolactin rise too) and "keeps working at full strength" (the response fades within weeks).

"Strongest" is roughly fair as a description of the acute GH pulse. It is not a description of a result.

Hexarelin vs ipamorelin, MK-677 and sermorelin

	Hexarelin	Ipamorelin	MK-677 (ibutamoren)	Sermorelin
What it is	Six-amino-acid GHRP; ghrelin receptor plus CD36	Five-amino-acid ghrelin-receptor agonist	Oral non-peptide ghrelin-receptor agonist	GHRH(1-29); acts on the GHRH receptor
GH release in humans	Near-maximal at 1 to 2 mcg/kg intravenously; about twice GHRH	One GH pulse per dose in a pharmacokinetic study of 40 men	Raised GH and IGF-1 with daily oral dosing	GH up at 1 to 2 mg a day; IGF-1 rise inconsistent
Cortisol and prolactin	Both rise	Not raised in animals; not measured in humans at clinic doses	Cortisol modestly raised over a year	Not a known effect
Outcome data	No adult benefit in 16 weeks; faster growth in a few short children	One failed trial in bowel recovery after surgery	Two-year trial in older adults: about 1 kg more fat-free mass, no strength gain, glucose up	Small trials in older adults; pediatric approval history
FDA status, October 2026	Never approved; in no FDA compounding category	Never approved; nominated but withdrawn for 503A, still Category 2 under the 503B policy; committee voted 0 yes, 12 no, 1 abstention in 2024	Never approved; Category 2; committee voted against in 2024	Formerly approved (Geref); compoundable on prescription
Typical monthly cost	No legitimate price	No legitimate price	No legitimate price	$150 to $400 (cost guide)

Hexarelin and ipamorelin are the pair people most often weigh against each other; our hexarelin vs ipamorelin comparison covers potency, side effects and desensitization side by side. The rest of the table is detailed in the CJC-1295 and ipamorelin profile, the best HGH peptides ranking and the HGH peptides guide. The practical point is the bottom two rows: of the four, only sermorelin can be prescribed and filled by a licensed pharmacy.

Dosage: what was studied versus what sellers circulate

Study	Dose and route	People	Result
Imbimbo 1994	0.5, 1 and 2 mcg/kg intravenously, single doses (about 35 to 140 mcg for a 70 kg adult)	12 healthy men	Dose-dependent GH rise; 2 mcg/kg near the maximum
Ghigo 1994	1.5 and 3 mcg/kg under the skin; 20 mcg/kg nasal; 20 and 40 mg by mouth	12 healthy young volunteers	All routes raised GH; the oral doses were 20 to 40 mg against 0.1 to 0.2 mg injected
Massoud 1996	0 to 1 mcg/kg intravenously	Healthy men	GH plateau at 1 mcg/kg; cortisol rose from 0.5 mcg/kg
Rahim 1998	1.5 mcg/kg under the skin twice daily for 16 weeks (about 105 mcg per injection at 70 kg)	12 healthy older adults	GH response down 45%; IGF-1 and body composition unchanged
Klinger 1996	60 mcg/kg nasal, three times daily, 6 to 10 months	7 short children	Growth velocity up; GH response halved
Frieboes 2004	50 mcg four times, hourly from 10 p.m.	7 young volunteers	Less deep sleep; GH, prolactin, ACTH and cortisol up
Seller and forum charts	100 to 200 mcg under the skin, once or twice daily, '8 to 12 weeks on, 4 off'	Self-experimenters	No controlled data on this schedule

The seller figures come from forum and seller dosing guides summarized in a 2026 review of self-administered GH-axis peptides (Dominikowski 2026). They are unusual among research-peptide charts in one respect: they are close to what was studied. A 70 kg adult injecting 1.5 to 3 mcg/kg under the skin takes 105 to 210 mcg, inside the seller range.

That makes the honest conclusion sharper, not softer. The schedule closest to the seller protocol, 1.5 mcg/kg twice daily, was tested for 16 weeks and produced a fading GH response with no change in IGF-1, fat, lean mass or bone (Rahim 1998). The "4 weeks off" in seller cycles happens to match the four weeks it took that response to recover, but recovering the pulse does not create the benefit the study never found.

We give no reconstitution example or units table for hexarelin, because there is no legal product to reconstitute: every vial for sale is a research product of unverified content. Our reconstitution calculator is built for medications a pharmacy has dispensed with a labeled concentration. The full breakdown of every studied dose, including the oral and nasal studies, is in our hexarelin dosage article.

Side effects and who should not use it

What the studies recorded. The documented effects are hormonal: prolactin rises of up to 180% and cortisol rises of about 40% after a single intravenous dose (Massoud 1996), and less deep sleep with higher ACTH and cortisol when dosed at night (Frieboes 2004). The published studies were single doses or a few weeks to months long in small groups, which is not enough to detect uncommon or long-term harms.

What users report. A 2026 review of people self-administering GH-axis peptides lists prolactin and cortisol elevations, appetite changes, blood sugar disturbances, fluid retention, muscle and joint aches and injection-site reactions, and notes that cortisol and prolactin effects are a feature of the older GHRPs, including hexarelin (Dominikowski 2026). The same review flags the unverified composition and dosing of products from unregulated supply chains.

The heart question. Hexarelin's acute effect on heart pumping is real in short human experiments (Broglio 2002), but it did not appear in dilated cardiomyopathy (Imazio 2002), and the receptor behind it also narrowed coronary vessels in animal hearts (Bodart 2002). Nobody has studied repeated doses in people with heart disease. That is not a profile anyone with heart disease should self-test.

Do not use hexarelin, and do not let anyone sell it to you, if you have:

an active cancer or a recent cancer history (GH and IGF-1 are growth signals);
diabetes, prediabetes or a strong family history of either;
coronary disease, heart failure or an arrhythmia;
a pituitary or adrenal disorder, including a prolactinoma or Cushing's disease, or are taking medication that affects prolactin or cortisol;
a sleep disorder, given the reduction in deep sleep;
pregnancy or breastfeeding.

Athletes subject to testing should treat it as prohibited: the World Anti-Doping Agency lists hexarelin by name among the growth hormone-releasing peptides banned at all times. For the broader picture of peptide risks, see peptide side effects.

Legal status in the United States

Our legal tracker explains the three tests a bulk ingredient must pass before a 503A pharmacy may compound it. Here is how hexarelin fares against each, as of October 2026.

A USP or NF monograph? None that we could find. Hexarelin was never an approved drug, which is how most substances acquire one.
A component of an FDA-approved drug? No. No hexarelin or examorelin product appears in FDA's approval database or on DailyMed, and as far as we could find it has never been approved anywhere.
On FDA's 503A bulks list? No. The list in federal regulations has six substances, none of them a peptide (21 CFR 216.23).
Covered by the interim policy for Category 1? No. Hexarelin is not in Category 1, 2 or 3 of FDA's nominations list updated May 14, 2026 (FDA categories 2026), and it is not on FDA's Category 2 page, either as a current entry or among the nominated-but-withdrawn substances (FDA Category 2 page).
The biologics exclusion does not apply, because hexarelin has six amino acids, not more than 40. It does not need to: it already fails every test.

What follows is simple. No state-licensed 503A pharmacy may legally compound hexarelin, and outsourcing facilities have no route either, since hexarelin is not a drug in shortage and FDA has never evaluated it for the 503B list. A prescription cannot make a non-compoundable substance compoundable.

Two misreadings are common. Hexarelin's absence from Category 2 does not mean FDA considers it safe; it means FDA has never evaluated it, because it is not on the nominations list at all. GHRP-2 and GHRP-6, its closest relatives, were nominated and sit in Category 3 for 503A and in Category 2 under FDA's 503B policy, as the tracker records. And a vial labeled "research use only" is not a legal workaround: FDA's 2026 warning letters treated research-labeled peptides sold with dosing guides and bacteriostatic water as unapproved drugs for human use, as the tracker documents.

Cost and the legal alternatives

There is no legitimate price for hexarelin, because there is no legitimate product. Anything sold as hexarelin in the United States in 2026 is a research vial or a clinic reselling one.

If the underlying goal is a clinician-supervised way to raise GH, the secretagogue a licensed pharmacy can dispense is sermorelin, at roughly $150 to $400 a month through telehealth; tesamorelin is available only as the brand Egrifta, at about $2,400 to $2,800 a month, and only makes sense for measured visceral fat (peptide therapy cost has the detail). Our complete guide to peptide therapy walks through the evaluation, labs and monitoring a legitimate prescription involves. If a clinic lists hexarelin on its menu, ask which pharmacy makes it and under what authority; our comparison of online clinics shows what each provider actually offers.

Older adults and women

Older adults were studied repeatedly, and the results cut against the anti-aging pitch. Their GH response to the peptide is less than half that of young adults (Arvat 1994), and the one long study, in healthy older adults, found the response fading with no change in IGF-1 or body composition after 16 weeks (Rahim 1998).

Most hexarelin studies enrolled men. We found no study of hexarelin in menopause and none designed to look at outcomes in women. It should not be used in pregnancy or while breastfeeding.

Bottom line

Hexarelin is a well-characterized 1990s research tool: a six-amino-acid peptide that releases a large pulse of growth hormone at microgram doses, raises prolactin and cortisol at the same time, loses part of its effect within weeks of regular use, and briefly strengthens heart contraction after an intravenous dose. What it has not done, in the one adult study long enough to look, is raise IGF-1 or change body composition. Its reputation as the strongest GHRP is about the size of the hormone pulse, not about anything a user would notice.

It also has no legal path to a patient in the United States. It was never approved, fails every 503A test and appears in none of FDA's compounding categories. If you want a GH secretagogue under medical supervision, the one a licensed pharmacy can dispense is sermorelin; if you want hexarelin, what you can buy is an unlabeled research vial.

Frequently asked questions

+What is hexarelin used for?

Nothing, officially: it has never been approved as a medicine anywhere we could find. In the 1990s researchers used it to study the growth hormone system, to test how much growth hormone a pituitary can release, and in a few small trials in short children and people with heart disease. Today it is sold as a research chemical and marketed online for muscle, fat loss, recovery and heart health, none of which has been shown in a human trial.

+Is hexarelin legal in the US?

Possessing it is not a crime, but no licensed US pharmacy may make it. Hexarelin is not FDA-approved, has no USP monograph we could find, is not on FDA's list of bulk substances pharmacies may use, and does not appear in any of FDA's compounding categories, so it fails every test in section 503A. Vials sold online as research chemicals are unapproved drugs when they are marketed for human use, and a prescription does not change that.

+What are the side effects of hexarelin?

The documented ones are hormonal. Single doses raise prolactin and cortisol along with growth hormone, and four doses at night reduced deep sleep while raising ACTH and cortisol. Reviews of people using growth hormone-releasing peptides on their own also list appetite changes, fluid retention, muscle and joint aches, blood sugar disturbances and injection-site reactions. Long-term safety has never been studied, and research vials add unknown content and sterility.

+Does hexarelin stop working over time?

Partly. In healthy older adults injecting it twice daily, the growth hormone response to a test dose was already lower after one week, significantly lower by week 4 and 45 percent lower at 16 weeks, and it returned to normal four weeks after stopping. In short children on nasal hexarelin the response halved within a week. The fade is real but partial and reversible; the bigger problem is that IGF-1 and body composition did not change in the 16-week adult study.

+Is hexarelin good for the heart?

It has an unusual acute effect: a single intravenous dose increased the heart's pumping fraction within minutes in healthy volunteers and in men with coronary disease during bypass surgery, which growth hormone itself did not do. In severe heart failure it worked in ischemic but not in dilated cardiomyopathy. There is no human study of repeated dosing for the heart, and in animal hearts the receptor behind the effect, CD36, also mediated narrowing of the coronary arteries.

+Is hexarelin stronger than ipamorelin?

Per dose it is probably the stronger growth hormone releaser, but the two have never been compared in the same study, so nobody can put a number on it. Hexarelin's extra strength comes with prolactin and cortisol rises that ipamorelin did not cause in animals. Neither can be legally compounded in the United States. Our hexarelin vs ipamorelin article compares them in detail.

+Can hexarelin be taken orally or as a nasal spray?

Both routes raised growth hormone in the 1990s studies, but very inefficiently. Compared with an intravenous dose, about 4.8 percent of a nasal dose and 0.3 percent of an oral dose was effectively available, so the oral doses tested were 20 to 40 milligrams, against roughly a tenth to a fifth of a milligram by injection. Capsules or sprays sold today have no verified content.

+Does hexarelin build muscle?

No study shows it. The only adult study that measured body composition gave 1.5 mcg/kg twice daily for 16 weeks to healthy older adults and found no significant change in lean mass, fat mass, bone density or IGF-1. No trial has measured strength or muscle growth in young adults or athletes.

+Is hexarelin banned in sports?

Yes. The World Anti-Doping Agency lists hexarelin, under its international name examorelin, among the growth hormone-releasing peptides in class S2, prohibited at all times, and anti-doping laboratories can detect it and its breakdown products in urine.