Trust Signals
This page is written by the FormBlends Medical Team and graded against peer-reviewed human clinical data, primarily from published trials by Ghigo, Arvat, Loche, and colleagues. Every major claim carries an explicit evidence rating. No dose recommendation is fabricated; where human data are absent, this page says so.
Key Takeaways
- Clinical trials used 1 to 2 mcg/kg per injection; for an 80 kg subject that is 80 to 160 mcg per dose, not a full 2 mg vial.
- Hexarelin causes measurable cortisol and prolactin elevation at standard doses, a documented disadvantage versus ipamorelin (Arvat et al., 1997).
- Pituitary desensitization occurs within 4 to 8 weeks of continuous daily use, reducing peak GH response even when the dose is unchanged.
- A 2 mg vial reconstituted in 2 mL bacteriostatic water yields 1000 mcg/mL; 0.1 mL equals 100 mcg, making dose math straightforward.
- Hexarelin is not FDA-approved for any indication. All human data come from research or off-label investigational use.
What Is the Right Hexarelin Dosage and Cycle?
Based on human clinical trial data, the research-grade hexarelin dosage is 1 to 2 mcg/kg per injection, given once to twice daily, subcutaneously or intravenously. Cycle lengths of 4 to 16 weeks have been studied; practical use typically stays at or below 8 weeks before a break to limit desensitization. A 2 mg vial is a sourcing unit, not a per-dose amount.
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- How hexarelin works: receptor targets and GH pulse numbers
- Evidence ledger: what the data actually support
- Hexarelin dosage table: weight-based, frequency, and cycle length
- What does hexarelin 2mg dosage mean on a label?
- How long should a hexarelin cycle run?
- When should hexarelin be injected?
- What most pages get wrong about hexarelin dosage
- Honest head-to-head: hexarelin vs. GHRP-6, ipamorelin, and sermorelin
- Reconstitution and label literacy: reading a COA and doing the math
- Side effects at clinical doses
- Frequently asked questions
How Hexarelin Works: Receptor Targets and GH Pulse Numbers
Hexarelin (hexarelin acetate, also called examorelin) is a synthetic hexapeptide: His-D-2-MeTrp-Ala-Trp-D-Phe-Lys-NH2. It is a growth hormone secretagogue receptor (GHSR-1a) agonist, meaning it binds the same receptor as endogenous ghrelin. GHSR-1a binding in somatotroph cells of the anterior pituitary triggers intracellular calcium mobilization and protein kinase C activation, driving pulsatile GH secretion.
Hexarelin also binds CD36, a scavenger receptor expressed in cardiac tissue. Early work by Broglio et al. (2002) and Muccioli et al. showed hexarelin exerted cardioprotective effects via CD36 independent of GH, which is why cardiac function studies formed part of its research history. This dual-receptor profile is pharmacologically interesting but also means cardiovascular effects at high doses are not purely GH-mediated.
In healthy adult volunteers, a single 2 mcg/kg IV dose produced peak serum GH values in the range of 40 to 90 mcg/L in studies by Arvat and Ghigo's group, compared to baseline values typically below 5 mcg/L. This roughly 10 to 20 fold stimulation is larger than typical GHRP-6 responses at equivalent doses in the same populations. The mechanistic caveat: peak GH from a single injection does not prove sustained anabolic effect, IGF-1 elevation, or body composition change over weeks. Those links require separate, longer-term evidence.
Evidence Ledger: What the Data Actually Support
| Claim | Best Evidence Type | Effect Direction | Confidence |
|---|---|---|---|
| Hexarelin stimulates acute GH release in healthy adults | Multiple human crossover trials (Ghigo, Arvat et al.) | Strong positive | High |
| Hexarelin raises cortisol and prolactin at standard doses | Human RCT/crossover (Arvat et al., 1997) | Positive (undesirable) | High |
| Pituitary desensitization with repeated dosing | Human repeat-dose studies (Loche et al.) | Blunted GH over time | Moderate to High |
| Cardiac protection via CD36 receptor | Animal models, limited human mechanistic data | Positive in animals | Low (human) |
| Improved body composition or muscle mass in healthy adults | No direct human RCT identified | Unproven | Very Low |
| GH deficiency correction with multi-week dosing | Small human trials (Loche et al., pediatric GHD) | Modest positive on IGF-1 | Low (small samples) |
| Synergistic GH release when combined with GHRH | Human crossover studies | Strong positive | Moderate |
Hexarelin Dosage Table: Weight-Based, Frequency, and Cycle Length
| Body Weight | Low End (1 mcg/kg) | Standard (2 mcg/kg) | Frequency | Cycle Length Studied |
|---|---|---|---|---|
| 60 kg | 60 mcg | 120 mcg | Once to twice daily | 4 to 16 weeks |
| 75 kg | 75 mcg | 150 mcg | Once to twice daily | 4 to 16 weeks |
| 90 kg | 90 mcg | 180 mcg | Once to twice daily | 4 to 16 weeks |
| 110 kg | 110 mcg | 220 mcg | Once to twice daily | 4 to 16 weeks |
These figures reflect doses used in published human research. They are not prescriptive recommendations. Doses above 2 mcg/kg per injection do not produce proportionally greater GH release in most human studies, consistent with receptor saturation kinetics. Going higher primarily increases side-effect exposure without meaningful additional GH benefit.
What Does Hexarelin 2mg Dosage Mean on a Label?
The 2 mg figure on a research peptide vial describes the total mass of lyophilized (freeze-dried) hexarelin in the vial, not a per-injection dose. Reconstituted correctly, 2 mg provides roughly 10 to 20 individual doses at typical research quantities.
Reconstitution math for a 2 mg vial: Add 2 mL of bacteriostatic water, yielding 1000 mcg/mL. On a standard 100-unit (1 mL) insulin syringe, each 10 units drawn equals 100 mcg. A 150 mcg dose requires drawing to the 15-unit mark. This is straightforward, but errors are common when users confuse mg with mcg or misread syringe gradations.
How Long Should a Hexarelin Cycle Run?
Human trial data support cycle lengths of 4 to 16 weeks. The practical constraint is desensitization. Loche and colleagues observed attenuated GH responses in children treated for GH deficiency during extended hexarelin courses. The mechanism involves two pathways: upregulation of somatostatin release (which opposes GH secretion) and probable downregulation of GHSR-1a at the pituitary with chronic agonist exposure.
A commonly applied research convention is 4 to 8 weeks on, followed by an off period of equal length to allow receptor resensitization. There is no direct human trial proving the optimal off period; the 4 to 8 week break recommendation is extrapolated from receptor pharmacology principles, not from a dedicated washout study. State that honestly when evaluating any protocol claiming precision here.
When Should Hexarelin Be Injected?
Timing matters for two reasons: endogenous GH rhythm and the somatostatin effect of fed states.
Endogenous GH is secreted in pulses, with the largest pulse typically occurring shortly after sleep onset. An injection timed to coincide with this window (30 to 60 minutes after falling asleep, or just before sleep) theoretically adds to the natural pulse rather than occurring during a high-somatostatin trough. However, this nighttime timing is operationally difficult.
More robustly supported: injecting in a fasted state. Glucose and fatty acids stimulate somatostatin release, which directly suppresses hexarelin-induced GH output. Clinical studies consistently administered hexarelin after an overnight fast or at least a 2-hour postprandial window. This is not arbitrary protocol hygiene; it is grounded in the somatostatin-ghrelin receptor antagonism documented in multiple human GH physiology studies.
For twice-daily dosing, morning fasted and late evening (pre-sleep, fasted) are the two timing windows most consistent with published research designs.
What Most Pages Get Wrong About Hexarelin Dosage
1. Treating desensitization as optional. Many blogs mention it in passing but continue recommending high-frequency dosing for months. Desensitization is not a rare adverse event; it is a predictable pharmacological consequence of continuous GHSR-1a agonism. In Loche et al.'s pediatric data, GH response declined meaningfully over extended treatment. Pretending this only happens at "excessive" doses is wrong.
2. Ignoring cortisol and prolactin. Hexarelin is one of the GHRP-class compounds most reliably associated with cortisol and prolactin co-secretion. Arvat et al. (1997) in the Journal of Clinical Endocrinology and Metabolism documented this clearly in healthy volunteers. Pages that list "no cortisol effect" for hexarelin are either confusing it with ipamorelin or fabricating data.
3. Presenting 2 mg as a dose. This is the most operationally dangerous error in popular hexarelin content and is addressed directly in the label literacy section above.
4. Claiming proven body composition benefits in healthy adults. No published human RCT has demonstrated significant fat loss or lean mass gain in healthy, non-GHD adults from hexarelin alone. The mechanistic pathway to such an outcome exists, but it is speculative at the population level.
5. Ignoring purity and sourcing reality. Research-grade hexarelin from unregulated peptide suppliers is not pharmaceutical-grade. Independent mass-spectrometry testing by organizations like Janoshik and others has found peptide content ranging widely from labeled claims, including contamination with related peptide fragments. A product labeled "hexarelin 2 mg" may contain 1.3 mg, 2.4 mg, or a partially oxidized form with different bioactivity. This is not a minor footnote; it directly affects every dose calculation on this page.
Honest Head-to-Head: Hexarelin vs. GHRP-6, Ipamorelin, and Sermorelin
| Attribute | Hexarelin | GHRP-6 | Ipamorelin | Sermorelin |
|---|---|---|---|---|
| GH pulse magnitude (acute) | Highest among GHRPs in most head-to-head data | High | Moderate | Moderate |
| Cortisol elevation | Yes, documented | Yes, documented | Minimal, key advantage | Minimal |
| Prolactin elevation | Yes, documented | Yes, documented | Minimal | Minimal |
| Hunger stimulation | Mild to moderate | Strong (ghrelin-like) | Minimal | Minimal |
| Desensitization speed | Faster than ipamorelin | Moderate | Slower | Slower |
| Human trial data | Yes, multiple adult and pediatric studies | Yes | Yes (limited published RCTs) | Yes, FDA-approved diagnostic use |
| FDA approval | No | No | No | Yes (diagnostic only; compounded therapeutic versions unapproved) |
| Where hexarelin loses | Cortisol/prolactin burden, faster tachyphylaxis | Hunger burden, cortisol | Lower peak GH | Lower peak GH, short half-life |
If minimizing cortisol and prolactin exposure is the priority, ipamorelin is the more selective GHSR agonist. Hexarelin's strongest evidence-based use case is maximum acute GH pulse when that peak magnitude matters more than side-effect profile, or in CD36-related cardiac research contexts.
Reconstitution and Label Literacy: Reading a COA and Doing the Math
What to look for on a Certificate of Analysis (COA):
- Purity by HPLC: Acceptable research grade is generally above 98% purity. Values below 95% mean a meaningful fraction of what you inject is not hexarelin.
- Identity confirmation: Mass spectrometry (MS) or LC-MS data confirming the molecular weight of hexarelin (887.04 g/mol for the free base) distinguishes it from related peptides or degradation fragments.
- Endotoxin testing: Bacterial endotoxins (LAL test) should be reported. Endotoxin contamination causes pyrogenic reactions and is a real risk with improperly manufactured peptides.
- Moisture content: Lyophilized peptides retain water. If the COA does not correct for moisture, actual peptide mass may be lower than the label claim.
Degradation flags: Reconstituted hexarelin that appears cloudy, has visible particulate matter, or has changed from colorless to yellow should be discarded. Methionine-containing peptides oxidize to methionine sulfoxide under light or heat exposure; hexarelin does not contain methionine, but its tryptophan residues (D-2-MeTrp) are susceptible to oxidation, which alters receptor binding. Store reconstituted vials at 2 to 8 degrees Celsius, away from light, and use within 28 days. Freeze lyophilized (dry) vials and avoid repeated freeze-thaw cycles.
Syringe math summary:
| Reconstitution Volume | Concentration | Syringe Units for 100 mcg | Syringe Units for 200 mcg |
|---|---|---|---|
| 1 mL added to 2 mg vial | 2000 mcg/mL | 5 units | 10 units |
| 2 mL added to 2 mg vial | 1000 mcg/mL | 10 units | 20 units |
| 4 mL added to 2 mg vial | 500 mcg/mL | 20 units | 40 units |
Side Effects at Clinical Doses
The following side effects have human-level evidence behind them, not just theoretical mechanism:
- Cortisol elevation: Documented in healthy volunteers in Arvat et al. studies. Magnitude is dose-dependent. Chronically elevated cortisol has catabolic and immunosuppressive consequences that partially offset GH-related anabolic signaling.
- Prolactin elevation: Documented in the same human studies. Sustained hyperprolactinemia can suppress reproductive axis function in both sexes.
- Water retention and edema: Common across GH secretagogues at effective doses, attributed to GH-mediated renal sodium retention and IGF-1 effects.
- Carpal tunnel symptoms: A class effect of GH elevation; numbness and tingling in the hands is reported at sustained effective doses.
- Injection site reactions: Redness, minor pain, nodule formation at subcutaneous sites are common with any peptide injection.
- Tachyphylaxis (reduced response): Not a subjective side effect but a pharmacological certainty with continuous use, discussed above.
Speculative risks (not established in human trials but mechanistically plausible): promotion of pre-existing malignancy via IGF-1 pathway; long-term effects on pituitary function after extended use. These are genuine unknowns, not proven harms, but they are the reason hexarelin has not reached clinical approval.
Frequently Asked Questions
What is the standard hexarelin dosage for research purposes?
Clinical trials used 1 to 2 mcg/kg per injection subcutaneously or intravenously. For an 80 kg subject, that translates to roughly 80 to 160 mcg per dose. The 2 mg vial is a common sourcing unit, not a single-dose amount.
How long is a typical hexarelin cycle?
Human data from Ghigo et al. and Loche et al. used cycles of 4 to 16 weeks at daily or twice-daily dosing. Beyond roughly 4 to 6 weeks of continuous use, GH pulse amplitude declines measurably due to pituitary desensitization and rising somatostatin tone.
What does hexarelin 2mg dosage mean on a product label?
2 mg is the mass of lyophilized peptide in the vial, not a single dose. Reconstituted in 2 mL bacteriostatic water, each 0.1 mL drawn yields 100 mcg. A typical research dose of 100 to 200 mcg therefore uses one to two of those draws per injection.
How often should hexarelin be injected per day?
Clinical studies used single daily doses or up to three injections per day. Because the GH-releasing effect desensitizes fastest with frequent dosing, many protocols space injections at least 3 to 4 hours apart and limit to twice daily to preserve pulse amplitude.
Does hexarelin raise cortisol and prolactin?
Yes. Unlike ipamorelin, hexarelin stimulates cortisol and prolactin release via ghrelin-receptor pathways outside the pituitary. Arvat et al. documented significant cortisol and prolactin rises after hexarelin in healthy adults. This is one of its key clinical disadvantages versus selective GHRPs.
What is hexarelin's half-life?
Hexarelin has a short plasma half-life estimated at roughly 30 to 60 minutes after subcutaneous injection based on GH pulse timing data in clinical studies. Its GH-stimulating effect peaks within 15 to 30 minutes and resolves within 2 hours.
How does hexarelin compare to GHRP-6 for GH release?
Hexarelin produces a larger peak GH response than GHRP-6 at equivalent doses in most head-to-head human studies, but it also causes faster desensitization and more pronounced cortisol and prolactin elevation. GHRP-6 adds significant hunger stimulation; hexarelin does not to the same degree.
What are hexarelin's main side effects at clinical doses?
The best-documented side effects are cortisol and prolactin elevation, water retention, fatigue, and injection-site discomfort. At repeated high doses, reduced GH response due to pituitary desensitization is a pharmacological certainty, not a rare event.
Should hexarelin be taken fasted?
Clinical studies typically administered hexarelin in a fasted state. Elevated blood glucose and free fatty acids from a recent meal blunt GH secretion via somatostatin, reducing the GH pulse amplitude. A fast of at least 2 hours before injection is therefore mechanistically justified.
Can hexarelin be combined with a GHRH analog?
Yes. Hexarelin plus a GHRH analog such as CJC-1295 produces synergistic GH release because they act on separate receptor pathways. This combination is used in research and some clinical contexts, but it also amplifies side-effect risk including greater cortisol and prolactin elevation.
How should a hexarelin 2mg vial be reconstituted?
Add 2 mL of bacteriostatic water slowly down the vial wall. Do not shake; gently swirl. This yields 1000 mcg/mL. Each 0.1 mL (10 units on a 100-unit insulin syringe) then equals 100 mcg. Store reconstituted vials refrigerated and use within 28 days.
Is hexarelin approved by the FDA?
No. Hexarelin has never received FDA approval for any indication. It has been studied in clinical trials for growth hormone deficiency and cardiac function but remains a research compound without approved therapeutic use in the United States.
Sources
- Ghigo E, et al. "Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man." Journal of Clinical Endocrinology and Metabolism. 1994;79(4):984-989.
- Arvat E, et al. "Endocrine activities of hexarelin, a synthetic GH-releasing peptide, in humans: comparison with GHRP-6, His-DTrp-Ala-Trp-DPhe-Lys-NH2." European Journal of Endocrinology. 1997;136(4):369-374.
- Loche S, et al. "The growth hormone-releasing activity of hexarelin in short normal children." Clinical Endocrinology. 1995;43(2):145-150.
- Broglio F, et al. "The endocrine and non-endocrine activities of GH secretagogues." European Journal of Endocrinology. 2002;146(Suppl 1):S35-S43.
- Muccioli G, et al. "Functional and binding studies of the GHS-R1a receptor." European Journal of Pharmacology. 1998;360(2-3):R1-R3.
- Ghigo E, et al. "Hexarelin: a potent GH-releasing peptide." Acta Paediatrica Supplement. 1994;406:70-73.
- Bowers CY. "GH releasing peptides: structure and kinetics." Journal of Pediatric Endocrinology. 1993;6(1):21-31.
- Howard AD, et al. "A receptor in pituitary and hypothalamus that functions in growth hormone release." Science. 1996;273(5277):974-977.