GHRP-6 (growth-hormone-releasing peptide 6) was one of the first synthetic peptides shown to release growth hormone through what is now known as the ghrelin receptor. It never became a medicine, but it became a standard laboratory tool, so most human doses on record are single intravenous test doses measured per kilogram. Medibact's GHRP-6 guide covers the molecule and its evidence; this page stays with figures.
What the human record holds
A census run on 2026-09-27:
| Source | Result |
|---|---|
| DailyMed | no label |
| ClinicalTrials.gov, "GHRP-6" | 0 registered studies |
| PubMed, GHRP-6 or GHRP6 in title/abstract | 704 records |
| … tagged as human | 245 |
| … tagged as clinical trial | 45 |
| … mentioning subcutaneous use | 20 (most in animals or horses) |
The doses in the human records fall into three groups:
| Use | Dose and route | Source |
|---|---|---|
| Diagnostic test (GH deficiency, adrenal insufficiency) | 1 mcg/kg IV, once | Horm Metab Res 2009 (PMID 19006049) and 2010 (PMID 19946832), 49 patients and 20 controls each |
| Combined test in children | 1 mcg/kg GHRH + 1 mcg/kg GHRP-6 IV | Horm Res 2008 (PMID 18772594), 70 children |
| Pharmacokinetics | 100, 200 and 400 mcg/kg IV, single doses | Cabrales et al., Eur J Pharm Sci 2013 (PMID 23099431), 9 men |
| Acute ischaemic stroke | 5 mg IV twice daily for 7 days, with EGF 75 mcg | COURAGE-2, J Clin Neurosci 2026 (PMID 42462342), 95 treated |
COURAGE-2 enrolled 188 patients; the combination did not improve disability at six months in the whole population, with a possible benefit in the 27 most severe strokes that the authors call a reason for further study. The trial was open-label and its sponsors' researchers are named in its conflict statement.
The per-kilogram figures in milligrams
| Body weight | 1 mcg/kg (test) | 100 mcg/kg | 200 mcg/kg | 400 mcg/kg |
|---|---|---|---|---|
| 60 kg | 60 mcg | 6 mg | 12 mg | 24 mg |
| 70 kg | 70 mcg | 7 mg | 14 mg | 28 mg |
| 80 kg | 80 mcg | 8 mg | 16 mg | 32 mg |
The spread is the story: the diagnostic dose and the pharmacokinetic doses differ by a factor of 100 to 400, and the stroke trial's daily total (10 mg) sits among the pharmacokinetic doses. Every one of them was given into a vein. The top pharmacokinetic dose at 70 kg is more than a 10 mg research vial holds.
What the protocol pages state
A protocol page dated August 2026 states 100 mcg per subcutaneous injection three times a day in weeks 1–2, 200 mcg in weeks 3–4 and 300 mcg in weeks 5–12, at least 4 hours apart, on an empty stomach — and adds that "no controlled human trial validates a GHRP-6 schedule for muscle gain or fat loss". Per day that is 300 to 900 mcg, between the single diagnostic dose and the smallest pharmacokinetic dose. The three-times-a-day pattern is consistent with the 2.5-hour elimination half-life measured after intravenous doses; no subcutaneous half-life has been published. The dosing frequency page sets that half-life beside other compounds'.
Units per vial size
GHRP-6 is counted in micrograms, so the table works in mcg/mL. Units on a U-100 syringe = mcg ÷ mcg/mL × 100. Research vials in this site's data are 2, 5 and 10 mg:
| Amount | 2 mg + 2 mL (1,000 mcg/mL) | 5 mg + 2 mL (2,500 mcg/mL) | 5 mg + 1 mL (5,000 mcg/mL) | 10 mg + 2 mL (5,000 mcg/mL) | 10 mg + 3 mL (3,333 mcg/mL) |
|---|---|---|---|---|---|
| 70 mcg (1 mcg/kg at 70 kg) | 7 | 2.8 | 1.4 | 1.4 | 2.1 |
| 100 mcg | 10 | 4 | 2 | 2 | 3 |
| 200 mcg | 20 | 8 | 4 | 4 | 6 |
| 300 mcg | 30 | 12 | 6 | 6 | 9 |
At these amounts the concentrated vials give readings of 1 to 6 units, where a single mark is a large share of the amount; the 2 mg vial and the larger water volumes give readings a syringe can resolve. How long a vial lasts follows directly: 5 mg at 300 mcg three times a day (900 mcg a day) is about five and a half days. The mg to mcg page covers the conversion, the insulin syringe units page the small barrels, and the GHRP-6 calculator any other vial. The ipamorelin dosage page reports a related secretagogue whose human doses were also intravenous.
What is not established
No regulator has reviewed any GHRP-6 dose, and no human study gave it under the skin on a repeating schedule. The pharmacokinetic study noted unexplained concentration spikes during elimination in four of its nine subjects. Whether a vial sold as GHRP-6 contains it, and how much, is not known without an assay. Nothing on this page is a dose or a schedule.
Sources and dates
Opened 2026-09-27: PubMed searches through NCBI E-utilities (GHRP-6/GHRP6 in title or abstract, with human, clinical-trial and subcutaneous filters, and with the 1 mcg/kg dose) and the abstracts of PMIDs 42462342, 23099431, 19946832, 19006049, 18772594, 11678828 and 8370708; ClinicalTrials.gov v2 search for GHRP-6; PubChem compound 4345065 (formula C46H56N12O6, weight 873.0); DailyMed search; one protocol page (dated August 2026), quoted for what it states. Per-kilogram, per-day and unit figures are arithmetic by this site. Corrections go to the contact page.