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. Its successor from the same research line, GHRP-2, is the only one licensed anywhere — as a single 100 mcg diagnostic injection in Japan — and the GHRP-2 dosage page reports that record.
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. Its relative GH potency and the hunger claim usually attached to it are weighed against its successor on GHRP-6 compared with GHRP-2. 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.