The potent older-generation GHRP — bigger GH pulse than ipamorelin, but with cortisol and prolactin elevations that have pushed most users to cleaner alternatives.
Hexarelin is a synthetic hexapeptide of the GHRP family (growth hormone releasing peptides). It activates the ghrelin receptor to trigger GH release, with higher potency than ipamorelin — but with the trade-off of meaningful cortisol and prolactin elevation at clinical doses.
Developed in the 1990s and extensively studied through the early 2000s. The clinical program was shelved largely because selective GHRPs (especially ipamorelin) offered most of the GH-pulse benefit with a much cleaner side effect profile.
Not FDA approved. WADA prohibited (S2). Available as a research chemical.
Hexarelin binds the GHS receptor more strongly than ipamorelin, producing a larger GH pulse per dose. The raw GH/IGF-1 numbers in early human trials were impressive.
Unlike ipamorelin, hexarelin activates the HPA axis enough to raise cortisol and prolactin at clinical doses. This is the main reason it fell out of favor for chronic use.
Separately from GH pulse, hexarelin has been studied for direct cardioprotective effects in animal models of ischemia. Independent of GH, not relevant to typical body-composition use.
Hexarelin’s higher potency comes with receptor tachyphylaxis. The 6-week dog study (PMID 10474131) showed the GH response actually primes up through week 3 before declining by week 6, with the downregulation being specific to hexarelin while GHRH response was largely preserved. The popular “4 weeks on” cycle is a reasonable middle ground, but the mechanism is more nuanced than a simple rapid shutdown at 4 weeks.
| Benefit | Evidence |
|---|---|
| GH elevation | Larger GH pulse than ipamorelin at equivalent doses in clinical trials |
| Cardioprotection (animal) | Reduced infarct size and improved ventricular function in rodent ischemia models — independent of GH pathway |
| Body composition | Lean mass gains + fat loss in short-term trials — similar magnitude to other GHRPs, not superior despite higher potency |
| Sleep quality | Pre-bed dose can improve slow-wave sleep, but the cortisol component may blunt the benefit for stress-sensitive users |
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Start Tracking Free“You have to cycle hexarelin” is repeated everywhere in this category, usually without a source. Here it has one, and the numbers are worth seeing.
Rahim et al. (Growth Hormone & IGF Research 1998, PMID 10990150) gave twice-daily subcutaneous hexarelin to 12 healthy elderly participants for 16 weeks and measured the GH response repeatedly. The area under the GH curve fell steadily:
| Week 0 | 19.1 mcg/L/hour |
| Week 1 | 13.1 |
| Week 4 | 12.3 (significant vs baseline) |
| Week 16 | 10.5 (significant vs baseline) |
By sixteen weeks the response had roughly halved (P = 0.0003 across the study).
Then the useful part. Four weeks after stopping, they dosed again. The GH response came back to 19.4 mcg/L/hour — statistically indistinguishable from where it started. The authors concluded the attenuation is partial and reversible.
That is unusually good news for a practice recommendation. The common protocol — run it for weeks, then take about four weeks off — matches what this study actually measured. It is one of the few places in this whole category where community practice and published data line up, and it is worth noticing precisely because it so often does not.
A companion paper from the same group (JCEM 1998, PMID 9589671) examined GH status during long-term hexarelin therapy.
Hexarelin raising cortisol and prolactin, unlike ipamorelin, is also a measured finding rather than an assumption. Arvat et al. (Peptides 1997, PMID 9285939) compared hexarelin and GHRP-2 head to head against GHRH and against a combined TRH/hCRH challenge in normal adults, tracking GH, prolactin, ACTH and cortisol together. Both peptides produced a stronger GH response than GHRH — and the same study is where the prolactin and ACTH/cortisol comparisons come from.
Hexarelin’s cardiac effects are not a downstream consequence of growth hormone. Bodart et al. identified a distinct GHRP binding site in heart tissue (Circulation Research 1999, PMID 10532947) and later showed that CD36 mediates the cardiovascular action (2002, PMID 11988484). Locatelli et al. (Endocrinology 1999, PMID 10465272) demonstrated cardioprotective effects in rats that were growth-hormone-independent — the protection persisted without the GH axis being responsible. Mao et al. reviewed the area (2014, PMID 25278975).
This is genuinely distinctive: most compounds in this section do one thing through one receptor. Hexarelin appears to act on the heart through a separate pathway entirely, which is interesting and also a reason its risk profile cannot be assumed to match the other GHRPs.
Not medical advice. These figures describe what is reported in the literature and what practitioners and communities do — not a recommendation, and for most compounds here no human dose-finding study exists. Talk to a qualified healthcare provider.
The desensitisation study above dosed 1.5 mcg/kg twice daily for 16 weeks subcutaneously — roughly 137 mcg per injection for a 91 kg person, which is close to the ranges used in practice. The comparison work (Arvat 1997) dosed 1–2 mcg/kg intravenously. Beyond those, no human dose-finding study exists for the protocols below.
Do not run continuously. Hexarelin desensitizes its own receptor faster than other GHRPs.
Ipamorelin (cleaner side effects, no tachyphylaxis issues) and CJC-1295+Ipamorelin (synergistic pulse) have largely replaced hexarelin in community protocols. It’s mostly used now by experienced users who specifically want the bigger per-dose GH pulse and accept the cortisol/prolactin cost.
Pre-filled with a typical Hexarelin setup. Edit any field — the draw updates live.
Insulin syringe — 100 units = 1 mL
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Not medical advice. These figures describe what is reported in the literature and what practitioners and communities do — not a recommendation, and for most compounds here no human dose-finding study exists. Talk to a qualified healthcare provider.
2 mg vial + 2 mL BAC water = 1 mg/mL = 1000 mcg/mL
| Dose | Volume | Syringe Units |
|---|---|---|
| 100 mcg | 0.10 mL | 10 units |
| 200 mcg | 0.20 mL | 20 units |
Hexarelin is a research peptide not approved by the FDA for human use. It is sold only as a research chemical, and StackTrax does not endorse or facilitate personal use.
Quality varies enormously among research-chemical suppliers. At minimum, look for:
Lyvn does not carry Hexarelin. They are the vendor we recommend elsewhere on this site, and they publish the full independent panel per batch — which makes their catalogue a useful yardstick for the criteria above even on a compound they do not stock. We are not recommending a specific supplier for Hexarelin itself, because we have no basis to.
For research use only. Not for human consumption. 21+.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeNo. Hexarelin was advanced through Phase 2 by Mediolanum / Pharmacia in the 1990s as a GH secretagogue but development was halted. It has never been FDA, EMA, or any other regulatory authority approved. Sold in the US only as a research chemical.
Community-practice dosing is 100–200 mcg subcutaneously 2–3 times daily. This is community/clinic convention — no Phase 3 chronic adult body-composition RCT exists. Rahim 1998 used 1.5 mcg/kg twice daily in elderly subjects (≈100 mcg in a 70 kg adult) and showed measurable tachyphylaxis by 16 weeks. Community doses of 200 mcg are nearly 2× the trial dose.
A typical reconstitution is 5 mg of hexarelin + 2 mL of bacteriostatic water, yielding 2.5 mg/mL. A 100 mcg dose draws to 0.04 mL (4 units on a 100-unit insulin syringe), 200 mcg = 0.08 mL (8 units).
Tachyphylaxis. Hexarelin has documented receptor desensitization with continuous chronic use — Rahim 1998 saw the effect within 16 weeks at 1.5 mcg/kg twice daily, and the desensitization reversed over a 4-week washout. The community "4 weeks on / 4 weeks off" protocol is an extrapolation of that finding to community-typical higher doses. Whether 4 weeks is adequate washout at 200 mcg doses (nearly double the trial dose) is not directly studied.
Both are GHRP-class GHSR-1a agonists. Hexarelin produces a larger GH pulse but also activates the cortisol/prolactin/ACTH axis (less selectively at the GH receptor). Ipamorelin is selective for GH — no cortisol/prolactin elevation. For chronic use, ipamorelin has a cleaner side-effect profile; hexarelin tends to be used for short, intense GH-mobilization periods.
Yes. Hexarelin is prohibited at all times under WADA S2.2 (Growth Hormone Secretagogues). No therapeutic-use exemption is available.
Disclaimer: This guide is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. The compounds discussed are not FDA approved for human use. Always consult a qualified healthcare provider before starting any new supplement or peptide protocol. StackTrax does not sell peptides or supplements directly — purchase links go to third-party vendors. StackTrax is not responsible for the products, quality, or business practices of any third-party vendor.
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StackTrax guides cover peptides and compounds that are not FDA-approved for the uses discussed. The dosing, reconstitution, and safety information is compiled from published research and community protocols for educational purposes only.
Before using any compound mentioned here, consult a qualified healthcare provider. StackTrax does not sell, prescribe, or recommend these substances for personal use.