Hexarelin Dosage Guide: Protocols, Desensitization, and the CD36 Question

What is Hexarelin?

Hexarelin, also called examorelin, is a synthetic six amino acid peptide developed in Italy in the early 1990s at Mediolanum Farmaceutici. Its sequence is His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, which is GHRP-6 with a methyl group added to the second tryptophan residue.

That single modification matters more than it sounds. It makes hexarelin substantially more potent at the ghrelin receptor on a microgram for microgram basis, and it largely strips out the intense hunger response that defines GHRP-6. On paper this looks like a straight upgrade, and for a single acute injection it more or less is.

The catch shows up on the calendar rather than in the vial. Hexarelin desensitizes its own receptor faster than any other compound in the growth hormone releasing peptide class, which turns a strong acute performer into a difficult long term tool. Almost every practical decision about hexarelin dosing follows from that one fact.

Mechanism of Action

Hexarelin is a growth hormone secretagogue that acts primarily at GHSR-1a, the same receptor ghrelin binds. Activation of GHSR-1a on pituitary somatotrophs triggers a phospholipase C cascade, raises intracellular calcium, and releases growth hormone from existing secretory granules. It also suppresses somatostatin tone at the hypothalamic level, so less of the released growth hormone is inhibited on the way out.

Why It Stacks With a GHRH Analog

GHRPs and GHRH analogs pull on different levers. A GHRH analog such as sermorelin or CJC-1295 increases the amplitude of a growth hormone pulse through the GHRH receptor. Hexarelin triggers the pulse through the ghrelin receptor and lowers the somatostatin brake at the same time. Used together the combined output is consistently reported as larger than either compound alone, which is the standard rationale behind every GHRH plus GHRP protocol on this site.

The Second Receptor

Hexarelin also binds CD36, a scavenger receptor found in cardiac muscle, macrophages and vascular tissue. This binding is unrelated to growth hormone release and is the reason hexarelin has a research literature that other GHRPs do not. That thread is covered in its own section below.

Half-Life

Hexarelin clears quickly, with a reported plasma half-life of roughly 55 minutes. The growth hormone pulse it triggers peaks around 20 to 30 minutes after subcutaneous injection and returns toward baseline within about two hours. Short action is the norm for this class and it is generally considered desirable, since a discrete pulse is closer to natural physiology than a sustained elevation.

Hexarelin Dosage Protocols

Hexarelin dosing is unusual in that the ceiling matters more than the floor. The receptor saturates at a low dose, so the useful question is not how much to take but how often, and for how long.

Standard Protocol

The Saturating Dose

Roughly 100 mcg, or about 1 to 2 mcg per kilogram, sits at or near the point where GHSR-1a is saturated. Past that point the growth hormone curve flattens while cortisol and prolactin keep climbing. A researcher who doubles the dose to 200 mcg is buying a meaningful increase in the side effect profile and very little extra growth hormone. This is the single most common dosing error with hexarelin and it is worth stating plainly: more is not more.

Dosing by Objective

Reconstitution

Hexarelin ships lyophilised, typically in 2 mg or 5 mg vials. Reconstituted with 2 mL of bacteriostatic water, a 2 mg vial yields 1000 mcg per mL, so 100 mcg is 10 units on a standard 100 unit insulin syringe. The full concentration tables are in the peptide reconstitution calculator, and the general handling procedure is covered in how to reconstitute peptides.

Why Fasting Matters

Insulin blunts growth hormone release at the pituitary. Injecting hexarelin on top of a recent meal wastes most of the pulse it would otherwise produce. The fasted window is not a refinement here, it is the difference between a strong response and a mediocre one.

The Desensitization Problem

This is the defining characteristic of hexarelin and the reason it never displaced the peptides it outperforms acutely.

Human studies using continuous daily administration found the growth hormone response was already attenuated at around two weeks and substantially blunted over four to sixteen weeks of uninterrupted use. Notably, IGF-1 tended to remain elevated even as the acute growth hormone pulse faded, which means the compound was still doing something downstream while the response researchers were measuring had largely gone.

The mechanism appears to be downregulation of GHSR-1a signalling rather than depletion of pituitary growth hormone reserves. The pituitary has not been exhausted, the receptor has stopped listening. Responsiveness returns after a washout period, which is why every practical hexarelin protocol is built around cycling rather than continuous use.

Cortisol and Prolactin

Hexarelin sits in the middle of the GHRP class on selectivity. It is cleaner than GHRP-6 on appetite but it is not clean on the adrenal and pituitary axes the way ipamorelin is.

At 100 mcg the rise in cortisol and prolactin is modest and broadly comparable to GHRP-2. At 200 mcg and above the picture changes: cortisol and prolactin scale with dose while growth hormone does not, so the risk to reward ratio deteriorates quickly. Sustained cortisol elevation works directly against the body composition and recovery outcomes most researchers are using a GHRP to pursue, and elevated prolactin over time can produce its own set of unwanted effects.

For anyone who needs cortisol and prolactin held flat, ipamorelin is the correct selection and hexarelin is the wrong one. The comparison between the older and newer generations of this class is covered further in sermorelin vs GHRP-6.

CD36 and the Cardiac Research

Hexarelin's affinity for CD36 gives it a research profile no other GHRP has. CD36 is a scavenger receptor expressed heavily in cardiac myocytes, macrophages and vascular endothelium, and hexarelin's binding there operates independently of growth hormone.

Animal work has reported reduced infarct size after induced ischemia, improved left ventricular function in post infarct models, and effects on vascular remodelling and lipid handling in macrophages. Some studies observed these effects in growth hormone deficient animals, which is the strongest evidence that the cardiac activity is not simply a downstream consequence of raised growth hormone.

Two caveats belong alongside that. First, essentially all of this work is preclinical. Small human studies have looked at hexarelin's cardiovascular effects but nothing approaching a controlled clinical trial programme exists, and hexarelin is not approved for any human indication anywhere. Second, CD36 biology is complex and its role in atherosclerosis and lipid uptake is not uniformly protective, so extrapolating from a rat infarct model to a human cardiovascular outcome is not warranted. The CD36 story is a genuinely interesting research thread, not a claim about what hexarelin does for people.

Hexarelin vs Other GH Secretagogues

Read the table as a set of tradeoffs rather than a ranking. Hexarelin wins on acute potency and loses on durability. Ipamorelin gives up peak output for a clean side effect profile and the ability to run for months. GHRH analogs sit underneath both as the structural base of a growth hormone protocol rather than competitors to either.

Side Effects and Safety Profile

Common

• Injection site reactions. Redness, mild swelling and soreness, most frequent in the first two weeks and usually managed by rotating sites.
• Water retention. Joint fullness, puffiness in the hands and a small scale weight increase are common early and typically settle within three to four weeks.
• Head rush or flushing. A brief warm or lightheaded sensation within the first 15 minutes of injection, reported fairly often with the more potent GHRPs.
• Tiredness after dosing. Most noticeable with bedtime injections and generally attributed to the growth hormone mediated deepening of slow wave sleep.
• Mild appetite increase. Far below GHRP-6 levels but not always absent.

Dose Dependent

• Cortisol elevation. Modest at 100 mcg, meaningful above 200 mcg. Chronic elevation undermines the outcomes the compound is usually chosen for.
• Prolactin elevation. Same dose relationship. Worth monitoring on longer or higher dose protocols.
• Reduced insulin sensitivity. Growth hormone is counter regulatory to insulin, so fasting glucose can drift upward, particularly on multi daily dosing.
• Numbness or tingling in the hands. Carpal tunnel type symptoms linked to water retention, more likely at higher total daily doses.

The broader class level picture, including what to monitor and when, is set out in the peptide side effects guide.

Cycling Strategy

Because the constraint is receptor desensitization rather than toxicity, cycling hexarelin is about preserving the response, not recovering from suppression.

The layered approach is the one most researchers land on. A GHRH analog such as sermorelin or CJC-1295 provides the continuous base because neither desensitizes meaningfully, and hexarelin gets added in defined four to six week blocks when a stronger pulse is wanted. Where hexarelin fits in a broader programme is covered in the muscle growth peptides overview.

Storage

Lyophilised hexarelin is stable at room temperature for short periods but should be refrigerated for anything longer. After reconstitution, keep it at 2 to 8 degrees Celsius, protect it from light, and use it within about 30 days. Do not freeze reconstituted peptide. Full handling detail is in the peptide storage guide.

Frequently Asked Questions