Hexarelin: research, side effects and dosage in studies
In short
Hexarelin (also called examorelin) is a synthetic growth hormone releaser that was studied a lot in humans in the 1990s [2]A. It has no marketing authorisation in Finland, and two published findings limit its use as a treatment: the effect weakens over weeks [1]E, not peer-reviewed, and it raises cortisol and prolactin [2]A.
- There are many human studies, mostly from the 1990s. Most are short experiments that measured growth hormone secretion [2, 5]A [6]B.
- The effect weakened: given twice a day for 16 weeks, the growth hormone response fell from 19.1 at baseline to 10.5. After a four-week break it returned to baseline. The finding comes from a short report in a supplement issue of a journal [1]E, not peer-reviewed.
- It does not release growth hormone alone: prolactin rose by up to 180 per cent from baseline and cortisol by about 40 per cent [2]A. According to the researchers, the cortisol effect runs at least partly through vasopressin [3]A.
- In Finland, hexarelin is in Annex 1 A of Fimea's medicines list, so it is controlled as a medicine and always treated like a prescription-only medicine [13]regulator. In sport it is banned at all times (WADA S2.2.4) [12]regulator.
- There is no approved dosage. All figures on this page are doses used in studies.
What is hexarelin?
Hexarelin is a synthetic peptide of six amino acids that makes the pituitary gland release the body's own growth hormone [2]A. It is a modified derivative of GHRP-6 with the sequence His-2-Me-D-Trp-Ala-Trp-D-Phe-Lys-NH2 [8]A. On the WADA list and Fimea's medicines list its other name is examorelin [12, 13]regulator.
Hexarelin belongs to the growth hormone releasers together with GHRP-2, GHRP-6 and ipamorelin, among others [4].
Hexarelin is not growth hormone, nor an analogue of IGF-1 like IGF-1 LR3. It acts at the upper end of the system. Hexarelin is one of the substances acting on growth hormone in the Peptides A-Z list.
Evidence at a glance
Each cell gives the kind of study and its source. The letter is the evidence level, not the result.
| Claimed effect | Humans | Animals | Cells |
|---|---|---|---|
| Growth hormone release | Dose-related rise, plateau 140 mU/l, ED50 0.48 µg/kg [2]A | - | - |
| Whether the effect lasts | Weakened over 16 weeks, 12 older people, recovered after a break [1]E, not peer-reviewed | - | - |
| Prolactin rise | Up to 180% from baseline, ED50 0.39 µg/kg [2]A | - | - |
| Cortisol and ACTH rise | Significant rise, 15 men; mediated by vasopressin according to the authors [3]A | - | - |
| Effect in growth hormone deficiency | Growth hormone rose in idiopathic deficiency, not when the pituitary stalk was interrupted; 19 patients [6]B | - | - |
| Effect on the thyroid | No effect on the TSH response to TRH, 7 adults [7]B | - | - |
| Safety | Appetite rose slightly [3]A; harms of the group in a review [4] | - | - |
"-" = no such study is known.
What is hexarelin studied for?
Hexarelin was studied in the 1990s by Italian and British endocrinology groups, mainly as a tool for studying how growth hormone secretion is regulated [2, 3, 5]A and in research on growth hormone deficiency [6]B. None of these is an approved use in Finland.
- Growth hormone deficiency: in 15 children and 4 adults with growth hormone deficiency, hexarelin raised growth hormone in idiopathic deficiency but hardly at all when the connection between the pituitary and the brain was interrupted [6]B.
- Hormone regulation: in healthy adults, studies measured how hexarelin affects growth hormone, prolactin, cortisol and thyroid regulation [2, 3]A [7]B.
- Pituitary tumours: in patients with acromegaly or excess prolactin secretion, studies measured how prolactin and growth hormone respond [8]A.
Muscle growth, fat loss and performance have not been studied, and according to a review these substances have no regulatory approval for such uses [4].
How does hexarelin work?
Hexarelin makes the pituitary gland release growth hormone, and it works differently from growth hormone releasing hormone, GHRH. The two have also been studied together: a small hexarelin dose strengthened the growth hormone response to GHRH [5]A.
In the growth hormone deficiency study, hexarelin hardly raised growth hormone in patients whose pituitary was cut off from the brain. According to the authors, this supports the view that in humans the effect is mediated through the hypothalamus [6]B.
The rise in cortisol and ACTH runs, according to the researchers' conclusion, at least partly through arginine vasopressin, not through corticotropin-releasing hormone, CRH [3]A.
Has hexarelin been studied in humans?
Yes, and more than most research peptides. There are many human studies, mostly from the 1990s. Most are short experiments that measured growth hormone secretion after a single dose [2, 5]A [6]B.
Human studies
- Dose response in healthy men. Healthy adult men received hexarelin into a vein at doses of 0-1.0 micrograms per kilogram. The growth hormone response levelled off at 140 milliunits per litre at a dose of 1.0 micrograms per kilogram, and the dose giving half the maximum response, the ED50, was 0.48 ± 0.02 micrograms per kilogram [2]A.
- The effect weakened within 16 weeks. Twelve healthy older people received hexarelin under the skin twice a day for 16 weeks. The area under the growth hormone curve was 19.1 ± 2.4 at baseline, 13.1 ± 2.3 at week 1, 12.3 ± 2.4 at week 4 and 10.5 ± 1.8 µg·h/l at week 16. The change over the whole period was significant (p = 0.0003), and the falls at weeks 4 and 16 were significant compared with baseline. Four weeks after the study ended, hexarelin was given again, and the response rose to 19.4, no longer different from baseline [1]E, not peer-reviewed. The study had no control group and was published as a short report in a supplement issue of a journal.
- Pituitary-adrenal axis. Fifteen healthy young men received hexarelin, corticotropin-releasing hormone (CRH) or desmopressin, alone and in combinations. Hexarelin significantly raised ACTH and cortisol, and CRH strengthened the effect. The authors concluded that hexarelin stimulates the pituitary-adrenal axis at least partly through arginine vasopressin [3]A.
- Patients with growth hormone deficiency. In 15 children and 4 adults with growth hormone deficiency, 2 micrograms per kilogram into a vein raised growth hormone in idiopathic deficiency much as in short control children [6]B.
The single most important finding is both a limitation and an observation: the effect faded with continuous use but returned after a break [1]E, not peer-reviewed. It comes from only one small study that was not published as an ordinary peer-reviewed article.
Who studies hexarelin?
Hexarelin was studied in the 1990s by Italian and British endocrinology groups, for example in Cagliari and Milan [6, 7]B and in London and Manchester [2, 3]A [1]E, not peer-reviewed.
Newer review literature mainly deals with the group being sold and self-administered without regulatory approval [4].
Who wrote this page: the editorial team
This page was written by the Molecular Recovery editorial team. The draft was made with the help of AI, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.
What are the side effects of hexarelin?
The main drawback of hexarelin is not a single symptom but the fact that it releases other hormones as well as growth hormone. This has been measured as a dose response [2]A.
Measured in humans
The same dose-response study that measured growth hormone also measured two other hormones. The prolactin response levelled off at a 180 per cent rise from baseline at a dose of 1.0 micrograms per kilogram, ED50 0.39 ± 0.02. Cortisol rose in a step of about 40 per cent at a dose of 0.5 micrograms per kilogram [2]A.
The ED50 for prolactin was lower than for growth hormone, 0.39 against 0.48. With hexarelin alone, prolactin therefore responded to smaller doses than growth hormone [2]A. When a very small hexarelin dose (0.125 micrograms per kilogram) was given together with GHRH, growth hormone rose a lot, prolactin moderately (about 85 per cent) and cortisol not at all [2]A.
The rise in ACTH and cortisol was confirmed in a separate study, which also measured symptoms on a visual analogue scale (VAS): hexarelin briefly increased appetite slightly [3]A. The prolactin-raising effect was also seen in people with acromegaly [8]A, and in the growth hormone deficiency study cortisol rose slightly [6]B.
What it did not affect
Hexarelin did not affect the TSH response to TRH in seven healthy adults [7]B, so in these measurements it did not interfere with thyroid regulation.
What has not been studied
No study of use beyond 16 weeks in adults is known [1]E, not peer-reviewed. Short children have been given it as a nasal spray for up to 8-10 months [14, 15]B. Performance or physique use has not been studied, and according to a review these substances have no regulatory approval for such uses. Users of the substance group have reported hormonal and metabolic disturbances, fluid retention, muscle and joint pain and injection-site reactions [4]. Peptide harms in general: side effects in studies.
Interactions and who has no data
No studies of drug interactions are known. All that is known is that growth hormone given from outside reduced the growth hormone rise caused by hexarelin [9]A, and that pyridostigmine strengthened the effect of a very small hexarelin dose [5]A.
In people with excess prolactin secretion, hexarelin's effect on prolactin disappeared and its effect on growth hormone weakened [8]A. No data are known for pregnancy or breastfeeding.
Evidence against and what is unknown
The strongest evidence against is the development of tolerance, and the effect is not limited to growth hormone.
Evidence against
- Tolerance. The growth hormone response fell by about 45 per cent from baseline in 16 weeks, and the fall was statistically significant. The authors asked in the title whether desensitisation to hexarelin occurs, and answered: partly, and the effect recovers after a break. They noted that clear fading with long-term use would seriously limit therapeutic use [1]E, not peer-reviewed.
- Lack of selectivity. Prolactin responds to smaller doses than growth hormone (ED50 0.39 against 0.48 micrograms per kilogram), and cortisol rose by about 40 per cent at 0.5 micrograms per kilogram [2]A.
- Dependence on the body's own state. Growth hormone given from outside reduced the growth hormone rise caused by hexarelin [9]A.
What the evidence does not support
- "Hexarelin builds muscle, burns fat or improves performance": none of this has been studied [4].
- "It can be used continuously without breaks": the response weakened with continuous use [1]E, not peer-reviewed.
- "Hexarelin is an approved medicine": it has no marketing authorisation in Finland.
- "The dose is known": the published doses are single test doses or study designs, not treatment guidance [1]E, not peer-reviewed [2]A.
What is not known
- What use beyond 16 weeks does in adults. The longest known adult study lasted 16 weeks, was small and had no control group [1]E, not peer-reviewed. The nasal spray studies in children lasted up to 8-10 months, also without a control group [14, 15]B.
- Whether the tolerance finding repeats in other studies. Only this one report is known [1]E, not peer-reviewed.
Hexarelin dosage in studies
Hexarelin has no approved dosage. Below are the doses used in human studies. They are not recommendations.
| Study | Who | Dose and route | Duration |
|---|---|---|---|
| Massoud 1996 | healthy adult men | 0-1.0 µg/kg into a vein; also GHRH 1.0 µg/kg alone or together with a small hexarelin dose (0.125 µg/kg) | single doses [2]A |
| Rahim 1998 | 12 healthy older people; no control group | under the skin twice a day; dose not reported | 16 weeks, repeat dose after a 4-week break [1]E, not peer-reviewed |
| Korbonits 1999 | 15 healthy young men | hexarelin alone or with CRH or desmopressin; dose not reported | 2 hours of follow-up [3]A |
| Arvat 1997 | 6 healthy men | 0.25, 0.5 and 2.0 µg/kg into a vein, alone or with pyridostigmine (120 mg by mouth) or GHRH | single doses [5]A |
| Loche 1995 | 15 children and 4 adults with growth hormone deficiency | 2 µg/kg into a vein | single dose [6]B |
What the numbers do not tell you. The figures in the dose-response study are single test doses into a vein, not treatment doses. They do not show a safe repeated dose. In the tolerance study the dosing was twice a day under the skin, and that is what led to the weaker response [1]E, not peer-reviewed. The dose response also differs between hormones: with hexarelin alone, prolactin responds to a smaller dose than growth hormone [2]A. A fuller table with sources: hexarelin doses used in studies. Unit converter: hexarelin calculator.
Hexarelin and CJC-1295: combinations
Combining hexarelin with CJC-1295 has not been studied in published human studies, but the principle behind the combination has been studied with other substances.
The idea of combining a growth hormone releaser with GHRH is that they act in different ways and together do more than either alone. This has been shown for hexarelin with GHRH [5]A and, separately, for GHRP-2 with GHRH [10]A.
That does not mean this particular combination of hexarelin and CJC-1295 has been studied. It has not, and there are no data on its safety. CJC-1295 has its own page: CJC-1295.
Is hexarelin legal in Finland?
Hexarelin has no marketing authorisation in Finland, so it may not be sold or marketed as a medicine. It is in Annex 1 A of Fimea's medicines list, so in Finland it is controlled as a medicine and always treated like a prescription-only medicine [13]regulator.
- Medicines list. Annex 1 A of Fimea's decision 230/2025 names "Heksareliini" (hexarelin), and Annex 1 lists the same substance as examorelin. Substances in Annex 1 A are always treated, by their effect, like prescription-only medicines [13]regulator.
- Fimea's warning. Fimea has specifically warned against using injectable peptides bought online [11]regulator.
- The label "research use only" is a classification label, not a permit for human use. That the substance was studied a lot in humans in the 1990s does not make it an approved medicine.
Overview of the law: peptides and the law in Finland. Bringing them from abroad: Travelling with peptides.
This is not legal advice. Disclaimer.
Is hexarelin doping?
Yes. WADA's 2026 Prohibited List names hexarelin in the group of growth hormone releasing peptides as "examorelin (hexarelin)" (S2.2.4). Substances in class S2 are banned at all times, in and out of competition [12]regulator.
How to assess a hexarelin product
There is no certainty about the contents of a hexarelin product without analysis. On a certificate of analysis (COA), check the test method and that the batch number matches the vial.
Liquid chromatography (HPLC) shows purity; mass spectrometry (MS) shows whether the molecule is the right one. How to read one: how to read a COA.
Hexarelin is a short peptide of six amino acids. It is also sold as hexarelin acetate; acetate is a salt form, not a different active substance. The names of growth hormone releasers are easily mixed up, so check the label: GHRP-2, GHRP-6, hexarelin and ipamorelin are different molecules with different hormone effects.
What a certificate does not tell you: sterility, endotoxin content, or what happened to the product in transport. On handling: mixing and storage.
FAQ
What is hexarelin?
Hexarelin (examorelin) is a synthetic peptide of six amino acids that makes the pituitary gland release the body's own growth hormone [2]A [12]regulator. It was studied a lot in humans in the 1990s but has no marketing authorisation in Finland.
What is the hexarelin dosage per day?
There is no approved dosage. Published single doses into a vein were 0.125-2 micrograms per kilogram, given as a test stimulus [2, 5]A [6]B, and in the longest adult study it was given under the skin twice a day for 16 weeks [1]E, not peer-reviewed. In that study the response weakened significantly. In short children the dose was 60 micrograms per kilogram as a nasal spray three times a day for up to 8-10 months [14, 15]B.
What results has hexarelin shown?
Growth hormone rose with the dose, up to 140 milliunits per litre [2]A. With continuous use the response weakened [1]E, not peer-reviewed. Muscle growth or performance has not been studied.
Does hexarelin keep working, or does tolerance develop?
Tolerance developed in one small study: given twice a day for 16 weeks, the growth hormone response fell from 19.1 to 10.5 (p = 0.0003), and after a four-week break it returned to baseline [1]E, not peer-reviewed.
What is hexarelin acetate?
Acetate is a salt form used in making peptides. It is not a different active substance from hexarelin.
Can hexarelin be used together with CJC-1295?
This combination has not been studied in published human studies. The combined effect of hexarelin and GHRH has been shown [5]A, but that is not the same as this combination.
What side effects does hexarelin have?
It raises prolactin and cortisol as well as growth hormone: prolactin by up to 180 per cent from baseline and cortisol by about 40 per cent [2]A. The rise in ACTH and cortisol was confirmed in a separate study, in which appetite also rose slightly [3]A.
Hexarelin experiences: what do studies say?
User accounts of hexarelin have not been compiled on this site. In studies the growth hormone response weakened with continuous use [1]E, not peer-reviewed, and the substance also raised prolactin and cortisol [2]A.
Is hexarelin legal in Finland?
It has no marketing authorisation in Finland, and it is in Annex 1 A of Fimea's medicines list, so it is always treated like a prescription-only medicine [13]regulator. Fimea has warned against using injectable peptides bought online [11]regulator. This is not legal advice.
Is hexarelin doping?
Yes. Hexarelin (examorelin) is named in section S2.2.4 of WADA's 2026 Prohibited List and is banned at all times [12]regulator.
Read the research yourself: sources
Every source opens the original publication or the regulator's page. The level shows what the source itself reports.
- Rahim A, Shalet SM. Does desensitization to hexarelin occur? Growth Horm IGF Res. 1998;8 Suppl B:141-143. Short report in a supplement issue. PMID 10990150 E, not peer-reviewed
- Massoud AF, Hindmarsh PC, Brook CG. Hexarelin-induced growth hormone, cortisol, and prolactin release: a dose-response study. J Clin Endocrinol Metab. 1996;81:4338-4341. PMID 8954038 A
- Korbonits M, Kaltsas G, Perry LA, et al. The growth hormone secretagogue hexarelin stimulates the hypothalamo-pituitary-adrenal axis via arginine vasopressin. J Clin Endocrinol Metab. 1999;84:2489-2495. PMID 10404825 A
- Dominikowski A, Rękoś Z, Olejarz M, et al. 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 (review)
- Arvat E, Di Vito L, Ramunni J, et al. Low hexarelin dose and pyridostigmine have additive effect and potentiate to the same extent the GHRH-induced GH response in man. Clin Endocrinol (Oxf). 1997;47:495-500. PMID 9404449 A
- Loche S, Cambiaso P, Merola B, et al. The effect of hexarelin on growth hormone (GH) secretion in patients with GH deficiency. J Clin Endocrinol Metab. 1995;80:2692-2696. PMID 7673411 B
- Arosio M, Casati G, Biella O, et al. Lack of effect of hexarelin on TRH-induced TSH response in normal adult man. J Endocrinol Invest. 1998;21:239-244. PMID 9624598 B
- Ciccarelli E, Grottoli S, Razzore P, et al. Hexarelin, a synthetic growth hormone releasing peptide, stimulates prolactin secretion in acromegalic but not in hyperprolactinaemic patients. Clin Endocrinol (Oxf). 1996;44:67-71. PMID 8706295 A
- Massoud AF, Hindmarsh PC, Brook CG. Hexarelin induced growth hormone release is influenced by exogenous growth hormone. Clin Endocrinol (Oxf). 1995;43:617-621. PMID 8548947 A
- Veldhuis JD, Bowers CY. Determinants of GH-releasing hormone and GH-releasing peptide synergy in men. Am J Physiol Endocrinol Metab. 2009;296:E1085-E1092. PMID 19240251 A
- Fimea. Fimea warns: do not use injectable peptides purchased online (29 Jun 2026). Fimea regulator
- World Anti-Doping Agency. 2026 Prohibited List, section S2.2.4: "examorelin (hexarelin)". WADA regulator
- Finland. Lääkeluettelo (Fimea medicines list), 230/2025, section 2, annex 1 A ("Heksareliini") and annex 1 ("Eksamoreliini"). Finlex regulator
- Laron Z, Frenkel J, Deghenghi R, et al. Intranasal administration of the GHRP hexarelin accelerates growth in short children. Clin Endocrinol (Oxf). 1995;43:631-635. PMID 8548949 B
- Klinger B, Silbergeld A, Deghenghi R, et al. 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;134:716-719. PMID 8766941 B
Sources read 13 Oct 2026; PubMed records, the WADA Prohibited List and Fimea's medicines list checked 14 Oct 2026. Source 1 is a short report in a supplement issue whose peer review could not be confirmed, so its level is E. Dose details are as given in the study abstracts.
Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.