Hexarelin

Plain-English version: hexarelin is a very short chain of six amino acids that acts like a "release GH now" signal to your pituitary gland. It imitates ghrelin — the natural hormone best known for driving hunger, which also happens to be one of the body's own GH triggers — but hexarelin is a purpose-built synthetic molecule, not a natural one.

Its amino-acid sequence is His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, and its International Nonproprietary Name is examorelin (hexarelin and examorelin are the same compound). It was developed by Romano Deghenghi and colleagues in Italy and belongs to the class of "growth-hormone-releasing peptides" (GHRPs) alongside ipamorelin, GHRP-2, and GHRP-6.

What sets hexarelin apart from almost every other research peptide is that it was genuinely studied in humans. In the 1990s, Italian endocrinology groups (led by Ghigo, Arvat, and Bisi) gave hexarelin to healthy young adults, elderly volunteers, children of short stature, GH-deficient adults, and obese subjects. Ghigo and colleagues showed in 1994 that it released GH by several routes — intravenous (IV), subcutaneous (SC), intranasal, and even oral — with injection being by far the most potent and the oral/nasal routes much weaker.^[1] These were acute pharmacology studies (measuring the GH response to one or a few doses), not long treatment trials.

The credibility caveat, up front: having human data is not the same as being an approved, proven drug. Hexarelin's development was discontinued and it never reached market. It is not FDA-approved for any indication, it is not a recognized 503A/503B compounding bulk substance, and it is sold only as a "research chemical." For the full legal picture, see Are Peptides Legal?

Takeaway first: hexarelin works through two separate receptor systems. One (GHSR-1a) drives the growth-hormone pulse that people take it for. The other (CD36) mediates heart-protective effects in animals and has nothing to do with GH. That "two switches, one molecule" design is what makes hexarelin pharmacologically interesting.

1. Growth-hormone release via the GHSR-1a (ghrelin) receptor

Hexarelin binds the growth-hormone-secretagogue receptor, GHSR-1a — the same receptor the natural hormone ghrelin uses — on GH-producing cells in the pituitary. Activating it triggers a rapid, dose-dependent pulse of GH. This pathway is distinct from GHRH (the body's other main GH trigger), which is why hexarelin and GHRH analogs add together when combined. A class review by Ghigo, Arvat, Muccioli, and Camanni described hexarelin as one of the most potent peptidyl GHRPs on this pathway.^[4] In a direct human comparison, Arvat and colleagues placed hexarelin alongside natural ghrelin and GHRH, confirming it as a potent non-natural peptidyl secretagogue with overlapping but distinct endocrine activity.^[6] Evidence level: human pharmacology studies.

2. It is not selective — it also nudges ACTH, cortisol, and prolactin

Here is an important honesty point. Unlike ipamorelin, which is prized for hitting GH almost exclusively, hexarelin also stimulates the stress-hormone axis. Arvat and colleagues documented that hexarelin raises not just GH but also ACTH, cortisol, and prolactin, and that these responses shift with age.^[3] This reduced selectivity is central to hexarelin's side-effect profile (covered below) and is the main reason it is not the first pick for long-term GH optimization. Evidence level: human.

3. Heart protection via the CD36 receptor (GH-independent)

Separately from GH, hexarelin acts on CD36 — a "scavenger receptor" found on heart-muscle cells and blood-vessel walls. Locatelli and colleagues showed in rats that hexarelin's cardioprotective effect persisted even when GH release was blocked, proving the heart effect is not a downstream consequence of GH.^[7] Bodart and colleagues then identified CD36 itself as the receptor carrying this cardiovascular action of GHRPs in the heart.^[8] More recent rat work found hexarelin protected heart-muscle cells from ischemia/reperfusion injury (the damage that occurs when blood flow is cut off and then restored) through interleukin-1 signaling.^[11] Evidence level: animal (rat) and cell studies — not human efficacy.

What we do NOT know

The human studies are short acute-pharmacology experiments. There is no modern, large-scale human trial establishing long-term efficacy, and the cardioprotection story — while mechanistically well-worked-out — rests on rat and cell data, not human outcomes. Direct human cardiovascular effects have been demonstrated (see below), but "hexarelin changes a measurement in humans" is not the same as "hexarelin prevents heart attacks in humans." No such claim is supported.

Plain-English version: the single most important practical fact about hexarelin is that it stops working as well the longer you use it without a break. Take it every day and the GH pulse it produces shrinks over a few weeks. This is why hexarelin is cycled rather than run continuously.

This is not internet folklore — it was measured in humans. Rahim, O'Neill, and Shalet followed GH status during long-term hexarelin therapy and documented that the GH response is attenuated with chronic administration.^[5] The likely mechanism is receptor desensitization: with sustained agonist exposure, the GHSR-1a receptor is internalized and its downstream signaling adapts, so the same dose produces a smaller response over time.

• Early weeks: robust GH pulse (full effect).
• Over continued daily use: the GH response progressively diminishes.
• Recovery: a washout period allows receptor sensitivity to return.

This distinguishes hexarelin from ipamorelin and GHRP-2, which hold their GH effect much better with continued use — which is precisely why those are preferred for sustained protocols. There is one silver lining: because the CD36 cardiac pathway is a separate receptor system, the heart effects in animal work do not appear to fade the same way the GH response does.^[7] We should note that the exact plateau percentages and timelines circulated online are not precisely pinned down by the primary human literature — treat "GH fades with continuous use, so cycle it" as the reliable, evidence-backed statement.

How to read this section: for each area we give the plain-English claim, the proposed mechanism, the population actually studied, the observed effect, and the limitation. Hexarelin is unusual in having genuine human GH data — but its cardiac benefits are animal-only, and no result here is a modern proof of a health outcome in people.

Potent growth-hormone release

Claim: hexarelin produces a strong, reliable pulse of GH. Mechanism: GHSR-1a activation on pituitary somatotrophs. Population: healthy young adults, elderly volunteers, and GH-deficient adults in Italian pharmacology studies. Effect: Ghigo and colleagues demonstrated robust GH release after injection in humans, with clear route-dependence (SC and IV strong; oral and nasal much weaker).^[1] Imbimbo and colleagues then mapped a dose-response curve, showing GH release rises with dose and then plateaus at higher doses — which is why later protocols cluster around a low microgram-per-kilogram range rather than pushing the dose ever higher.^[2] Limitation: these are acute studies of the hormone response itself, not trials of muscle, fat, recovery, or aging outcomes. A GH pulse is a measurement, not a guaranteed real-world benefit.

Works even in older and GH-deficient subjects

Claim: hexarelin still releases GH when the pituitary's own output has declined. Mechanism: direct receptor stimulation that partly bypasses age-related regulatory decline. Population: elderly volunteers and GH-deficient adults. Effect: Arvat and colleagues compared responses across ages and found hexarelin retained meaningful GH-releasing activity in the elderly, though absolute peaks were lower than in the young; the same work documented that the accompanying ACTH/cortisol/prolactin responses are also age-modulated.^[3] Limitation: again, short pharmacology studies of the hormone response, not long-term treatment outcomes.

Heart protection (the distinctive one — animal evidence)

Claim: hexarelin may protect heart tissue from injury. Mechanism: CD36-receptor activation, independent of GH, plus interleukin-1 signaling. Population: rats (whole-animal ischemia models) and cardiac cells. Effect: Locatelli and colleagues showed GH-independent cardioprotection — the benefit remained when GH was blocked;^[7] Bodart and colleagues identified CD36 as the mediating receptor;^[8] and Huang and colleagues showed protection against ischemia/reperfusion injury via interleukin-1 signaling.^[11] Limitation: this is rodent and cell evidence. It is genuinely interesting mechanism work, but it is not proof that hexarelin protects human hearts.

Direct cardiovascular activity in humans

Claim: hexarelin has measurable heart and circulation effects in people, beyond releasing GH. Mechanism: direct cardiac/hemodynamic activity (consistent with the CD36 pathway seen in animals). Population: healthy human volunteers and hypopituitary adults. Effect: Bisi and colleagues demonstrated acute cardiovascular and hormonal effects of hexarelin in humans,^[9] and in a separate study documented cardiac effects (left-ventricular function) in hypopituitary adults — patients who make little GH — reinforcing that the cardiac action is not simply a GH effect.^[10] Limitation: these show the compound is cardiovascularly active in humans; they do not show it treats or prevents any heart disease.

The honest bottom line on "benefits"

• The GH data are real and human — but they are short pharmacology studies of the hormone response, not outcome trials.
• The cardioprotection story is animal-only for actual tissue-protection outcomes; the human cardiac data show activity, not therapeutic benefit.
• Development was discontinued. There are no modern, large-scale, FDA-registration trials.
• Desensitization limits how much sustained benefit is realistic from continuous use.

Read this first: the doses below come from published human research, but hexarelin is not an approved drug and there is no validated "treatment" dose for real-world GH optimization. The best-characterized human dosing sits in the low microgram-per-kilogram range, established by the early Italian studies. We describe protocols here for completeness and harm reduction, not as medical guidance for self-administration of an unapproved compound.

Research doses (from the human literature)

Route	Commonly cited dose	Frequency	Typical use	Note
Subcutaneous (SC)	1–2 mcg/kg (~100–150 mcg)	1–2x daily	GH release	Most-used research route; fasted
Intravenous (IV)	1.5–2 mcg/kg	Single dose	Acute GH stimulation testing	Clinical/diagnostic setting only
Older / GH-deficient adults	~1.5 mcg/kg	Twice daily	Lower weight-scaled dosing	Reduced pituitary reserve

Imbimbo and colleagues showed the GH response is dose-dependent but plateaus at higher doses — so pushing the dose up does not keep buying more GH, it mostly buys more cortisol and prolactin.^[2] That plateau is exactly why the ~1–2 mcg/kg range became the reference. Ghigo and colleagues confirmed injection is far more effective than oral or nasal routes, so SC is the practical research route.^[1]

Reconstitution math, with a worked example

Hexarelin ships as a lyophilized (freeze-dried) powder that must be mixed with bacteriostatic water before use. The core formula:

Concentration (mcg/mL) = vial amount (mcg) ÷ water added (mL)

Worked example: take a 2 mg vial (that is 2,000 mcg) and add 2 mL of bacteriostatic water. That gives 2,000 ÷ 2 = 1,000 mcg/mL. To draw a 100 mcg dose: 100 ÷ 1,000 = 0.10 mL, which is 10 units on a standard 100-unit insulin syringe. A 150 mcg dose is 0.15 mL, or 15 units.

Vial	BAC water	Concentration	100 mcg	150 mcg
2 mg	2 mL	1,000 mcg/mL	0.10 mL (10 units)	0.15 mL (15 units)
2 mg	1 mL	2,000 mcg/mL	0.05 mL (5 units)	0.075 mL (7.5 units)
5 mg	2.5 mL	2,000 mcg/mL	0.05 mL (5 units)	0.075 mL (7.5 units)
5 mg	5 mL	1,000 mcg/mL	0.10 mL (10 units)	0.15 mL (15 units)

Preparation: wipe the stopper with alcohol; draw the water; inject it slowly down the inside wall rather than blasting the powder; swirl gently (do not shake) until dissolved; label the vial with the date and concentration. Use the peptide calculator and bacteriostatic water calculator to check volumes, and the reconstitution guide for a full walkthrough.

Timing: fasted matters

Like all GH secretagogues, hexarelin's GH effect is blunted by food — carbohydrates most, protein also. The convention is no food for about 2 hours before a dose and 30 minutes after. Common timing windows are morning (before breakfast), pre-workout (if fasted), and bedtime (at least 2 hours after dinner, pairing with the natural overnight GH pulse). The CD36 cardiac pathway appears less food-dependent than GH release, since it runs through a separate receptor.

Cycling (because of desensitization)

• Cycle, do not run continuously. Because the GH response fades with chronic use,^[5] hexarelin is used in on/off cycles with a washout to let receptor sensitivity recover. A commonly cited pattern is roughly 4 weeks on / 2 weeks off.
• Bridge with a different GHRP if needed. During the off period, some protocols switch to ipamorelin or GHRP-2, which do not desensitize the same way and do not cross-desensitize hexarelin.
• Stack with GHRH, not with other GHRPs. Hexarelin adds synergistically with GHRH analogs (sermorelin, CJC-1295) because they hit a complementary pathway. Combining it with another GHRP (ipamorelin, GHRP-2, GHRP-6) is pointless — they compete for the same receptor, so you get no extra GH, just extra cortisol and prolactin.

None of the above is a recommendation to self-administer an unapproved compound. It is a description of how the research doses are structured.

Straight talk: in the published human pharmacology studies, hexarelin was generally well tolerated at research doses with no serious adverse events reported — but those studies were short, and there are no modern controlled safety trials for chronic use. The defining safety difference from cleaner GHRPs is that hexarelin is less selective: it raises cortisol, ACTH, and prolactin along with GH.^[3]

Reported and expected effects

Effect	Mechanism / frequency	Notes
Cortisol / ACTH elevation	Dose-dependent; documented in humans	More than ipamorelin/GHRP-2; can offset anabolic goals and affect sleep/mood
Prolactin elevation	Dose-dependent; documented in humans	Can affect libido, mood; rarely galactorrhea; menstrual changes in women
Appetite stimulation	Common (ghrelin-mimetic)	Less intense than GHRP-6, more than ipamorelin
Loss of GH effect over time	Predictable with continuous use	Desensitization; the reason for cycling
Injection-site reactions	Common, mild	Redness, mild soreness; rotate sites
Transient flushing / warmth	Common, post-injection	Vasodilatory; usually minutes
Transient blood-pressure changes	Documented cardiovascular activity in humans	Hexarelin is directly cardioactive; caution with cardiac conditions
Mild water retention	Occasional (GH-mediated)	Usually subtle
Tingling / joint aches	Uncommon (GH/IGF-1 class effect)	More with sustained high GH

Because Bisi and colleagues showed hexarelin has direct cardiovascular effects in humans,^[9] anyone with a cardiovascular condition should treat it as a compound with real hemodynamic activity, not an inert supplement.

Why the cortisol and prolactin matter

This is the practical trade-off with hexarelin. Sustained mild cortisol elevation can drive visceral (belly) fat, work against muscle, disrupt sleep, and affect mood — partly undoing the very reasons someone would use a GH secretagogue. Prolactin elevation can reduce libido and, less commonly, cause galactorrhea or menstrual irregularity. Both are dose-dependent and reverse on stopping. This is the single biggest reason ipamorelin — which barely touches cortisol or prolactin — is preferred for long, steady protocols.

Who should avoid it

• Anyone with hyperprolactinemia or a prolactin-secreting tumor — hexarelin raises prolactin further.
• Cushing's syndrome or conditions worsened by cortisol (severe osteoporosis, poorly controlled diabetes, severe depression) — use caution or avoid.
• Active or recent cancer — GH and IGF-1 are growth-promoting; considered off-limits until specifically studied.
• Uncontrolled diabetes or active diabetic retinopathy — GH antagonizes insulin and can worsen retinopathy.
• Pregnancy and breastfeeding — no safety data; avoid.
• Significant cardiac disease or recent ischemic events — hexarelin is directly cardioactive; medical supervision only.

Interactions to know

• Insulin / sulfonylureas: GH opposes insulin — monitor glucose.
• Glucocorticoids (prednisone, dexamethasone): additive cortisol burden — avoid combining.
• Other GHRPs: compete at the same receptor — no benefit, just more side effects.
• GHRH analogs (sermorelin, CJC-1295): synergistic and commonly paired.

For broader context, see Are Peptides Safe? and Peptide Side Effects. The biggest under-appreciated risk with any unregulated research peptide is product quality — impurities can cause reactions that get blamed on the peptide itself.

Why this section matters: hexarelin is an unregulated research compound, so purity and identity vary widely between suppliers. For an unapproved peptide, contamination can be a bigger practical risk than the peptide itself. The single most useful skill is knowing how to read a Certificate of Analysis (COA).

What a credible product should show

• Third-party COA: independent HPLC purity testing (look for ≥98%) plus mass-spectrometry identity confirming the expected molecular weight of hexarelin.
• Batch-specific results: the COA should reference the exact lot you are buying, not a generic sample.
• Endotoxin testing (LAL): important for anything intended to be injected.
• Proper form and packaging: lyophilized powder in a sealed, light-protected vial.

Red flags

• No COA, or a COA from the seller rather than an independent lab
• Pre-mixed "ready to use" liquid (shorter shelf life, contamination risk)
• Prices far below the market
• Explicit human-use or medical claims, which signal a non-compliant, higher-risk vendor

Legal and regulatory status (2026)

• Not FDA-approved for any indication. Hexarelin (examorelin) was investigated in human trials in the 1990s–2000s but development was discontinued and it never reached market.
• Not a recognized compounding substance: it is not an approved drug and is not a recognized 503A/503B compounding bulk substance.
• Sold only as a "research chemical." Any vendor marketing it for human use is out of compliance.
• Sports: GH secretagogues are prohibited by anti-doping authorities, so competitive athletes should treat hexarelin as bannable.

Storage

Keep unopened lyophilized vials cold and dark (freezer for long-term, refrigerator short-term). Once reconstituted, refrigerate at 2–8°C, use within about 28 days, protect from light, and avoid freeze-thaw cycles; discard anything cloudy or discolored. See the full peptide storage guide. For the complete legal picture, read Are Peptides Legal?

Hexarelin is usually weighed against its GHRP neighbors. None of these comparisons come from head-to-head human outcome trials — they contrast the human pharmacology and the animal literature.

Feature	Hexarelin	Ipamorelin	GHRP-2	GHRP-6
Acute GH potency	Very high	Moderate	Very high	High
Holds up with chronic use	Fades (desensitization)	Stable	Mostly stable	Stable
Cortisol / prolactin	Notable rise	Minimal	Moderate	Significant
Appetite	Moderate	Minimal	Moderate	Intense
Distinctive angle	CD36 heart effects (animal)	Cleanest side-effect profile	Maximum GH potency	Appetite + GH
Best fit	Short cycles; cardiac research	Long-term GH use	Strong GH pulses	Bulking / appetite

For long, steady GH support, ipamorelin or GHRP-2 are generally the better choices because they keep working and stay cleaner on cortisol and prolactin. Hexarelin's niche is short, intensive cycles and its unique cardiac-research angle. See the hexarelin vs ipamorelin comparison for a deeper side-by-side.

Quick answer: research-grade hexarelin usually runs roughly $30–60 for a 2 mg vial and $50–90 for a 5 mg vial, depending on supplier and purity testing. At a common 100–150 mcg per dose, a 2 mg vial provides on the order of 13–20 doses.

Item	Typical cost
2 mg vial (research grade)	$30–60
5 mg vial (research grade)	$50–90
Bacteriostatic water	$8–15
Insulin syringes (box)	$10–15

Because hexarelin is cycled and adds synergistically with a GHRH analog, many research stacks budget for both. As always, price should never outweigh a verifiable third-party COA — a cheap, untested vial is the most expensive mistake you can make with an unregulated compound.