Not approved, and not even on a listHexarelin has no FDA approval and does not appear on any 503A or 503B category list, so no pharmacy nomination has been evaluated.[1][4][5] This page does arithmetic and reports the published record; it does not suggest amounts.
What is hexarelin?
Hexarelin is a synthetic hexapeptide growth hormone secretagogue, structurally GHRP-6 with a 2-methyl group added to its D-tryptophan.[21][22]
- Sequence
- His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, 6 residues, amide end[21]
- Formula and weight
- C47H58N12O6, 887.0 g/mol; CAS 140703-51-1[21]
- Difference from GHRP-6
- One CH2 group, 14 g/mol: 873.0 becomes 887.0[22][21]
- Other names
- Examorelin (its INN), EP-23905, MF-6003[21]
The methylated tryptophan is not one of the 20 standard amino acids, so the sequence molecular weight calculator cannot model hexarelin directly; it gives GHRP-6's weight, to which the extra CH2 is added.
Hexarelin's regulatory status
Hexarelin occupies an unusual position: it is absent from every FDA compounding category list and from the FDA's safety page, because no one nominated it.[4][5][3]
| Question | Answer |
|---|---|
| Approved in the U.S.? | No application found in Drugs@FDA[1] |
| Orphan designation? | None for hexarelin or examorelin[2] |
| On a 503A or 503B category list? | No, on none of them[4][5] |
| Reviewed by the advisory committee? | No review found |
| In the HHS October 2026 policy? | No; that policy lists six peptides, not including hexarelin[6] |
| Enforcement action? | Yes: a December 2025 warning letter to an active-ingredient distributor[7] |
The 2025 letter is worth reading carefully, because it is narrower than it looks. The FDA wrote that the firm's drug listing for "Hexarelin Acetate" named the active ingredient as "peptide B27PD", so the product was not properly listed under section 510(j)(1)(C) and was misbranded under section 502(o).[7] The letter is about how the substance was listed, not a finding that hexarelin itself is an unapproved drug. Being absent from the lists is not permission either, as are peptides legal? explains.
What the hexarelin studies found
Hexarelin was studied seriously in the 1990s as a growth hormone stimulus and later for heart function; its most important finding for anyone considering repeated use is that the response weakened over 16 weeks.[12]
| Study | Design and people | Route | Reported |
|---|---|---|---|
| Ghigo 1994[9] | 12 healthy young volunteers | Intravenous, under the skin, intranasal and oral compared | Growth hormone response about twice that of GHRH. Bioavailability by response: 77% under the skin, 4.8% intranasal, 0.3% oral |
| Imbimbo 1994[10] | Double-blind, placebo-controlled rising dose, 12 healthy men | Intravenous | Response near its maximum at the top of the range tested |
| Laron 1994[11] | 10 children with familial short stature plus 2 GH-deficient adults | Intravenous vs intranasal | Similar peaks by both routes; the GH-deficient patients did not respond |
| Rahim 1998[12] | Adults, 16 weeks of twice-daily use | Under the skin | The growth hormone response fell by about half and recovered 4 weeks after stopping. IGF-I, body composition and bone density unchanged |
| Rahim 1999[13] | Same 16-week regimen | Under the skin | The cortisol response fell by week 16, then recovered; prolactin unchanged |
| Frieboes 2004[14] | 7 healthy young volunteers, placebo-controlled | Overnight | Less slow-wave sleep; growth hormone, prolactin, ACTH and cortisol rose |
| Broglio 2002[15] | 24 patients having coronary bypass surgery | Intravenous, single use | Ejection fraction and cardiac output rose within 10 minutes, by a mechanism not mediated by growth hormone |
| Imazio 2002[16] | 13 patients with severe cardiomyopathy | Intravenous, single use | Ejection fraction rose in ischemic but not dilated cardiomyopathy |
- The 16-week finding. Growth hormone rose less by week 16 while IGF-I, body composition and bone density were unchanged: a measurable hormone response without a measurable body change.[12]
- Not selective. Like GHRP-6, hexarelin moves cortisol, prolactin and ACTH as well as growth hormone, and it reduced deep sleep in the one sleep study.[13][14]
- No registered trials. ClinicalTrials.gov lists no study with hexarelin as an intervention.[8]
Amounts above are what researchers used under medical supervision, not doses for anyone. The HGH peptides page compares this record with sermorelin, tesamorelin and ipamorelin.
Hexarelin vs ipamorelin
Both act on the ghrelin receptor and neither is approved, but they differ in two ways that matter: ipamorelin is the more selective of the two by the FDA's own account, and only ipamorelin has been formally reviewed, and rejected, for compounding.[17][18]
| Hexarelin | Ipamorelin | |
|---|---|---|
| Size | 6 amino acids, 887.0 g/mol | 5 amino acids, 711.85 g/mol[23] |
| Selectivity | Raised prolactin, ACTH and cortisol alongside GH[14][13] | The FDA describes it as more selective for growth hormone[17] |
| FDA compounding lists | On none[4][5] | 503B Category 2[5] |
| Advisory committee | Never reviewed | Voted against, October 2024[18] |
| Longest human study | 16 weeks, twice daily, under the skin[12] | Intravenous only; a phase 2 after bowel surgery[17] |
| Response over time | Weakened by week 16, recovered after stopping[12] | Not studied beyond short courses |
| WADA 2026 | S2.2.4, named as examorelin[19] | S2.2.4, named[19] |
Hexarelin is the only one of the two with a multi-week study in people, and that study is the reason to be careful rather than reassured: the hormone response faded while nothing measurable changed in the body.[12] See GHRP-6 for the closest relative and HGH peptides for the whole family.
Hexarelin and sport
Hexarelin is prohibited at all times: WADA's 2026 list names "examorelin (hexarelin)" in the S2.2.4 list of growth hormone-releasing peptides.[19] S2 substances are non-Specified, and USADA keeps GHRPs under S2 for the 2027 list.[20] Details on are peptides banned in sports?
Hexarelin weight math
At 887.0 g/mol, 1 mg of hexarelin is 1,127 nmol, slightly fewer molecules than the same weight of GHRP-6 (1,145 nmol) because hexarelin is 14 g/mol heavier.
| Vial + liquid | mg/mL | mcg per unit | nmol per unit | Units per 100 mcg |
|---|---|---|---|---|
| 2 mg + 1 mL | 2 | 20 | 22.55 | 5 |
| 2 mg + 2 mL | 1 | 10 | 11.27 | 10 |
| 5 mg + 1 mL | 5 | 50 | 56.37 | 2 |
| 5 mg + 2 mL | 2.5 | 25 | 28.18 | 4 |
| 10 mg + 1 mL | 10 | 100 | 112.74 | 1 |
| 10 mg + 2 mL | 5 | 50 | 56.37 | 2 |
For the arithmetic behind the table, see the peptide dosage calculator.
Other peptide pages
The peptides most often looked up alongside this one. Each page gives that peptide's FDA status, compounding status and published human evidence, with sources; the status table has all 23 in one place.
- TesamorelinFDA-approved Egrifta SV and Egrifta WR. Labeled doses, diluents and volumes.
- CJC-1295 / ipamorelinNot approved Two growth-hormone secretagogues, often sold together. Both rejected for compounding in 2024.
- SermorelinDiscontinued Once sold as Geref. Discontinued in 2008, not for safety reasons.
- AOD-9604Not approved Growth hormone fragment. Obesity trials failed; committee voted 0–12.
- GHRP-6Not approved Growth hormone-releasing hexapeptide. On FDA 503B Category 2.
- BPC-157Not approved 15-amino-acid peptide. Human data: a few tiny, uncontrolled studies.
Frequently asked questions
Is hexarelin FDA-approved?
What is the difference between hexarelin and GHRP-6?
Does hexarelin stop working over time?
The growth hormone response weakened over 16 weeks of twice-daily use in the one study that ran that long, and recovered four weeks after stopping.[12]
Is hexarelin banned in sport?
Yes. WADA's 2026 list names "examorelin (hexarelin)" under S2.2.4, prohibited at all times, in and out of competition.[19]
Sources
- openFDA Drugs@FDA searches for thymalfasin, thymosin, kisspeptin, emideltide, hexarelin, examorelin, GHRP, cathelicidin and Zadaxin (no match)
- Search orphan drug designations and approvals (thymalfasin: 4 designations; kisspeptin, hexarelin, emideltide, cathelicidin: none)
- Certain bulk drug substances for use in compounding that may present significant safety risks
- Bulk drug substances nominated for use in compounding under section 503A (category lists)
- Bulk drug substances nominated for use in compounding under section 503B (category lists)
- Enforcement discretion policy regarding 503A compounding using certain peptide bulk drug substances (91 FR 68526)
- Warning letter: Darmerica, LLC (API distributor)
- ClinicalTrials.gov searches: hexarelin, GHRP-6, emideltide and DSIP as interventions (0 studies)
- Ghigo E et al. Hexarelin by intravenous, subcutaneous, intranasal and oral routes in humans (J Clin Endocrinol Metab 1994;78:693–698)
- Imbimbo BP et al. Hexarelin: rising-dose, placebo-controlled study in healthy men (Eur J Clin Pharmacol 1994;46:421–425)
- Laron Z et al. Intranasal vs intravenous hexarelin in children with short stature (Clin Endocrinol 1994;41:539–541)
- Rahim A et al. Partial, reversible attenuation of GH response after 16 weeks of hexarelin (J Clin Endocrinol Metab 1998;83:1644–1649)
- Rahim A et al. Adrenal and prolactin responses during 16 weeks of hexarelin (Clin Endocrinol 1999;50:77–84)
- Frieboes RM et al. Hexarelin and sleep EEG in healthy volunteers (Psychoneuroendocrinology 2004;29:851–860)
- Broglio F et al. Hexarelin and cardiac function after coronary bypass surgery (Eur J Pharmacol 2002;448:193–200)
- Imazio M et al. Hexarelin in severe ischemic vs dilated cardiomyopathy (Eur J Heart Fail 2002;4:185–191)
- FDA briefing document: ipamorelin-related bulk drug substances
- Pharmacy Compounding Advisory Committee, October 29, 2024: transcript (ipamorelin and kisspeptin-10)
- World Anti-Doping Code: Prohibited List 2026
- Athlete advisory: what's new on the 2027 WADA Prohibited List
- PubChem CID 6918297: examorelin (hexarelin)
- PubChem CID 9919153: growth hormone releasing hexapeptide (GHRP-6)
- PubChem CID 9831659: ipamorelin