Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
Hexarelin produces one of the largest acute GH pulses of the GHRP class, the GH dose-response plateaus around 1.0 mcg/kg IV (peak ~140 mU/L; ED50 0.48 mcg/kg; Massoud et al. 1996, PMID 8954038). In the one direct human comparison, equal doses of hexarelin and GHRP-2 produced statistically similar GH, prolactin, ACTH and cortisol responses (Arvat et al. 1997, PMID 9285939): so it is not clearly more potent than GHRP-2, despite a common community claim that it is "the strongest GHRP." WADA prohibited (S2 category). It stimulates the pituitary's own GH release rather than providing exogenous GH, but the elevation is well beyond natural pulsatile release, and, unlike Ipamorelin, it meaningfully raises cortisol and prolactin. Rated 4, consistent with the other GHRPs (GHRP-2, GHRP-6, Ipamorelin), since the acute GH/IGF-1 stimulus is comparable in magnitude across the class; hexarelin's real differentiators are faster receptor desensitization and GH-independent CD36 cardioprotective activity, not superior GH potency.
Overview
A synthetic hexapeptide GHRP long regarded in community/vendor use as the strongest of the class, though the one direct human comparison study found its GH, cortisol and prolactin responses statistically similar to equal doses of GHRP-2 rather than clearly superior. Its standout feature is a unique cardioprotective action via CD36 receptor binding on cardiomyocytes, independent of GH release. It desensitizes faster than alternatives like Ipamorelin and elevates cortisol/prolactin more than that selective peptide. Better suited for short-run/pulsed use: a 16-week continuous human trial showed GH responsiveness declining significantly within the first week and continuing to decline through week 16.
Important Warnings
- •Most desensitization of all GHRPs - GH response drops 50-75% after 4-16 weeks
- •Cycle 4+ weeks off between uses to restore sensitivity
- •Elevates cortisol and prolactin more than Ipamorelin
- •Not FDA-approved for any indication
- •WADA prohibited - detectable via mass spectrometry; short plasma half-life means the practical urine detection window is brief, but a specific published detection time for hexarelin itself is not well established
- •Ceiling effect around 1 mcg/kg - higher doses show diminishing returns
- •Hyperglycemia possible with high doses/long-term use
- •Inject on empty stomach (food blunts GH response)
- •Chronic high-dose use may cause gynecomastia from prolactin
Purpose & Use Cases
Maximum GH Release
One of the strongest acute GH pulses of the GHRP class. The GH dose-response plateaus around 1.0 mcg/kg IV (peak ~140 mU/L, ED50 0.48 mcg/kg), a direct human comparison found this response statistically similar to equal doses of GHRP-2, not clearly superior.
Cardioprotection
Unique CD36-mediated cardiac effects independent of GH, involving PI3K/Akt prosurvival signaling. Significantly reduced infarct size in rat ischemia-reperfusion models. Improved left ventricular ejection fraction in human GH-deficient adults in an acute-dose study (cardiac output unchanged in that trial); chronic dosing improved cardiac output and stroke volume in a rat post-MI heart-failure model.
IGF-1 Effect Is Uncertain
Evidence on chronic IGF-1 elevation is mixed. A 16-week human trial of twice-daily hexarelin found no significant IGF-1 change despite a real (if declining) GH pulse (Rahim et al. 1998, PMID 9589671), and a chronic-dosing rat study found the same GH/IGF-1 dissociation. Some reviews report IGF-1 rising with prolonged GHRP use generally, but a specific, reliable percentage for hexarelin is not well established.
GH Stimulation Testing
Used in research for pituitary function assessment. 1-2 mcg/kg IV bolus, GH measured at 0, 15, 30, 45, 60, 90, 120 minutes.
Benefits
- Among the strongest acute GH pulses of the GHRP class - statistically similar to GHRP-2 in direct human testing
- GH dose-response plateaus near 1.0 mcg/kg (peak ~140 mU/L in clinical dosing studies)
- Unique cardioprotective effects via CD36 receptor, independent of GH release
- Improves left ventricular ejection fraction in GH-deficient adults
- Less appetite stimulation than GHRP-6
- Not a controlled substance
- Well-characterized acute pharmacokinetics (SC bioavailability ~64% in animal PK studies)
Good to Know
Widely called the strongest GHRP: and the one that burns out fastest
Community and vendor sources commonly describe hexarelin as the most potent GHRP, but the one formal human head-to-head trial (equal 1-2 mcg/kg doses of hexarelin vs. GHRP-2) found their GH, cortisol and prolactin responses statistically similar rather than hexarelin being clearly superior. What is well established: hexarelin's high receptor affinity causes the fastest tachyphylaxis of the class, a 16-week continuous-dosing human trial found GH output already declining within the first week and continuing to fall through week 16 (50-75% lower efficacy over weeks to months per long-term data), reversible about 4 weeks after stopping. Treat it as a short-run/pulse tool, cycle off 4+ weeks, or rotate to ipamorelin, rather than running it continuously.
It is not "clean" like ipamorelin
As a strong ghrelin-receptor (GHSR-1a) agonist, hexarelin also bumps cortisol (via the HPA axis) and prolactin (direct pituitary effect), unlike selective ipamorelin, which raises GH without meaningfully touching either. So chronic high-dose hexarelin can bring prolactin-type sides; ipamorelin trades raw potency for a much cleaner hormonal profile.
Unique heart effect via CD36
Hexarelin binds the CD36 scavenger receptor on heart muscle and shows cardioprotective effects that are INDEPENDENT of GH release (reduced infarct size in animal models, improved function in GH-deficient patients). That CD36 action is a genuinely distinctive feature not shared by the other GHRPs.
Pairs with a GHRH, on an empty stomach
Like the other GHRPs, combining hexarelin with a GHRH analog (Mod GRF 1-29 / CJC-1295) produces a synergistic GH pulse 2-3x larger than either alone. Inject on an empty stomach: food (especially fat/carbs) blunts the GH response.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 100 – 100 mcg/day |
| Intermediate | 100 – 200 mcg/day |
| Advanced | 200 – 300 mcg/day |
Weight-based: roughly 1-1.5 mcg/kg per injection (~100mcg for a 70-100kg adult). The GH dose-response plateaus around 1.0 mcg/kg IV in clinical dosing studies (Massoud et al. 1996) - doses much above that show diminishing returns. Desensitization is faster than other GHRPs: a 16-week continuous twice-daily human trial (1.5 mcg/kg BID) showed a significant GH decline within the first week that continued through week 16, reversible ~4 weeks after stopping (Rahim et al. 1998). Community protocols typically favor shorter 4-8 week runs (vs. 8-12 weeks for GHRP-2/Ipamorelin) with a 4+ week washout, or rotation with Ipamorelin. Often combined with GHRH analogs (CJC-1295, Mod GRF 1-29) for synergistic GH release. SC bioavailability ~64% in animal PK studies; human SC bioavailability is not well characterized.
Plasma half-life is 55-70 minutes, but the functional effect outlasts it: the GH pulse peaks at 15-30 minutes and GH remains elevated for roughly 4-6 hours after a dose.
Side Effects
Flushing
commonMost common side effect. Warmth/redness at injection site, lasts 5-15 minutes.
Self-limiting. No intervention needed.
Water Retention
commonPeripheral edema, especially extremities. Related to GH effects.
May persist during use. Monitor sodium intake.
Cortisol Elevation
commonDose-dependent increase with no clear plateau in clinical dosing studies (~40% rise at 0.5 mcg/kg; may run higher at the 1-2 mcg/kg doses used in practice). Peak 30-60 min, returns to baseline 2-4 hours. More than Ipamorelin, roughly similar to GHRP-2.
Usually subclinical. Space doses to allow cortisol normalization.
Prolactin Elevation
commonDose-dependent increase, plateauing around +180% above baseline at doses of 1 mcg/kg and above (ED50 ~0.39 mcg/kg). Peak 15-30 min, duration 1-2 hours. Roughly similar in magnitude to GHRP-2; may be more significant with chronic high-dose use.
Monitor for gynecomastia symptoms. Consider Ipamorelin if prolactin-sensitive.
Lethargy/Fatigue
commonPost-injection fatigue lasting 1-2 hours.
Time injections appropriately. Pre-bed dosing avoids this issue.
Desensitization
commonGH response decreases 50-75% after 4-16 weeks continuous use. More pronounced than other GHRPs.
Cycle off 4+ weeks for partial recovery, or rotate with Ipamorelin.
Increased Appetite
uncommonLess than GHRP-6 but still present. Duration 30-60 minutes.
Time around meals if problematic.
Carpal Tunnel Symptoms
uncommonNumbness, tingling in hands. Related to GH/IGF-1 elevation.
Reduce dose or discontinue. Usually resolves.
General Mitigation Strategies
Hexarelin causes more cortisol/prolactin elevation than selective peptides like Ipamorelin. Space injections to allow hormones to normalize. Significant desensitization (50-75% response reduction) after 4-16 weeks - cycle 4+ weeks off or rotate with other GHRPs. Pre-bed dosing minimizes fatigue impact. Monitor for gynecomastia with chronic high-dose use.
Post Cycle Therapy (PCT)
Does not affect HPT axis. No PCT required. Does cause pituitary desensitization to GH release - allow 4+ week recovery between cycles.
How It Works
Binds to GHSR-1a (ghrelin receptor) on pituitary somatotrophs, activating phospholipase C via Gq/11 coupling, increasing intracellular calcium and triggering GH exocytosis. Also stimulates hypothalamic GHRH neurons and suppresses somatostatin. Unique CD36 scavenger receptor binding on cardiomyocytes activates prosurvival PI3K/Akt signaling, providing cardioprotection independent of GH effects; reviews note the full cytoprotective signaling picture is still incompletely characterized.
Fundamentals
Reference on the practices relevant to Hexarelin: how they are done and where they go wrong. Not a recommendation to use it.
Common Stacks
- Hexarelin 100-200mcg + Mod GRF 1-29 100mcg - synergistic 2-3x GH release
- Rotate: Hexarelin 4-8 weeks, then Ipamorelin 8-12 weeks to avoid desensitization
- Pre-bed injection for GH pulse during sleep
- Do not combine with other GHRPs (same receptor, no additive benefit)
- Consider for cardiac recovery protocols due to unique CD36 cardioprotection
Legal Status
Not FDA-approved for any indication and not a controlled substance; sold as a research chemical. WADA prohibited (S2 category).
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
Hexarelin (Examorelin) is prohibited at all times under WADA category S2 as a growth hormone-releasing peptide (GHRP).
References
- Synthetic growth hormone-releasing peptides (GHRPs): historical appraisal, mechanism (GHS-R1a) and CD36-mediated cardiovascular actions (review, PMC5392015)
- Massoud et al. 1996: Hexarelin-induced growth hormone, cortisol and prolactin release: a dose-response study (J Clin Endocrinol Metab, PMID 8954038)
- Rahim, O'Neill & Shalet 1998: Growth hormone status during long-term (16-week) hexarelin therapy: progressive GH desensitization, IGF-1 unchanged (J Clin Endocrinol Metab, PMID 9589671)
- Arvat et al. 1997: GHRP-2 and hexarelin produce similar GH, prolactin, ACTH and cortisol responses in man (Peptides, PMID 9285939)