Quick answer: there is no approved GHRP 6 dosage. In human studies, GHRP-6 was usually given once by IV at 0.1 to 1 mcg per kg, which caused a short growth hormone burst peaking 45 minutes after an infusion started and back to baseline by 3.5 hours.[1][2] Other studies tested it by nose (5 to 30 mcg per kg), by mouth (300 mcg per kg), and as a 5 mg IV dose twice daily for a week in Cuban stroke patients.[9][7][13]
This guide lists every human dose we found, what each did, and why online protocols are not trial doses. For background, see our GHRP-6 profile, GHRP-6 side effects and the growth hormone peptides hub.
Why there is no standard GHRP-6 dose
GHRP-6 is a lab-made six-amino-acid peptide (a hexapeptide) that makes the pituitary gland release growth hormone.[1] It was studied mainly as a research tool and a diagnostic test, and we found no FDA approval, so there is no label dose. A 2026 review of performance peptides, including GHRP-6, highlights the uncertainty around their claimed performance and body-composition benefits.[17]
That leaves two kinds of numbers: research doses, given under supervision with frequent blood tests, and online doses, which do not come from trials.
IV doses in healthy adults
| Study | Who | Dose | Growth hormone result |
|---|---|---|---|
| First human study, 1989 | 17 healthy men | 0.05 to 2.5 mcg/kg as a 30-minute IV infusion | Consistent rise from 0.25 mcg/kg; average peak 63 micrograms/L at 1 mcg/kg[1] |
| Tulane, 1990 | 18 healthy men | 0.1, 0.3 or 1 mcg/kg IV bolus | Average peak 7.6, 16.5 and 68.7 micrograms/L[2] |
| Japan, 1991 | 6 healthy men | 1 mcg/kg IV bolus | Average peak 54.9 micrograms/L[9] |
| Germany, 1995 | Healthy men | 4 IV doses of 50 mcg during one night | Higher growth hormone, ACTH and cortisol overnight[11] |
| Cuba, 2013 | 9 healthy men | 100, 200 or 400 mcg/kg IV once | Pharmacokinetics only: elimination half-life about 2.5 hours[6] |
In the first study, growth hormone peaked 45 minutes after the infusion began and returned to baseline by 210 minutes.[1] At Tulane, prolactin and cortisol about doubled, but only at the 1 mcg per kg dose.[2] The Cuban pharmacokinetic study used doses about 100 to 400 times higher than the hormone studies, to measure how the body clears the drug rather than to find a useful dose.[6]
Diagnostic test doses
GHRP-6’s one established medical use was as part of a hospital stimulation test:
- GHRH plus GHRP-6: 1 mcg per kg of each, IV, once. In 125 adults with pituitary disease and 125 healthy controls, it separated growth hormone-deficient adults from healthy ones, and no adverse events were reported.[3]
- GHRP-6 alone or with GHRH: 1 mcg per kg IV. In 20 patients in Hamburg, both versions identified every growth hormone-deficient patient that the insulin tolerance test did, and flushing was the only side effect.[4]
- Adrenal testing: 1 mcg per kg IV was also tried to test cortisol reserve in 49 patients and 20 controls. It activated the stress-hormone axis with no detectable side effects but was less accurate than the insulin test.[5]
These tests use a single dose, in hospital, to read the body’s maximum response.
Doses by nose, mouth and under the tongue
| Route | Who | Dose | Result |
|---|---|---|---|
| Nasal | 6 healthy men, Japan | 5, 15 or 30 mcg/kg | Dose-related peaks of 7.5, 14.1 and 39.6 micrograms/L[9] |
| Nasal, repeated | Same men | 15 mcg/kg every 8 hours, 7 doses | No loss of effect; IGF-1 rose from 94.5 to 125.8 micrograms/L[9] |
| Oral | 5 healthy men, 9 children with short stature | 100 or 300 mcg/kg | Clear rise in men, weaker or absent in 5 of 9 children; oral had about 0.3% of IV activity[7] |
| Oral | 13 children with normal short stature | 300 mcg/kg | Response similar to IV GHRH[8] |
| Oral, nasal, under the tongue | Healthy young men, sleep study | 300 mcg/kg oral; 30 mcg/kg nasal or under the tongue | Nasal raised overnight growth hormone; oral and under-the-tongue had little or no effect[10] |
The sleep study authors concluded that GHRP-6’s effects depend on dose, duration and route.[10] These are the only non-injected human doses we found, and all are decades old.
Repeated dosing: stroke trials and clinic records
Two settings used GHRP-6 repeatedly:
- Stroke trials in Cuba: in a phase I/II trial, 36 patients received 75 mcg of epidermal growth factor (EGF) plus either 3.5 mg or 5 mg of GHRP-6 by IV twice daily for 7 days, compared with standard care. The authors judged it safe.[12] The phase III COURAGE-2 trial then gave 95 patients EGF plus 5 mg GHRP-6 twice daily for 7 days. It missed its main goal of reducing disability at 6 months; a possible benefit in severe strokes needs confirming.[13]
- US clinic chart review: men on testosterone were prescribed 100 mcg each of GHRP-6, GHRP-2 and sermorelin three times daily. In the 14 men who met strict inclusion criteria, IGF-1 rose from about 160 to 239 ng/mL after an average of 134 days. The study reported hormone levels only, not muscle, fat loss or safety outcomes.[14]
Timing, frequency and combining with GHRH
- Pulse length: growth hormone rose within the hour and returned to baseline in about 3.5 hours after a single IV dose.[1]
- Combining with GHRH: at 0.1 and 0.3 mcg per kg, GHRP-6 plus 1 mcg per kg of GHRH released more growth hormone than the two added together.[2] This is why GHRP-type peptides are often paired with GHRH analogs such as sermorelin, but the pairing was tested as a diagnostic test, not a treatment.
- Loss of effect: nasal doses every 8 hours for 2 to 3 days did not lose effect in one small study.[9] We found no human data on daily use over months.
What FDA says
- Not approved: we found no FDA approval for GHRP-6.
- Outsourcing facilities (503B): since September 29, 2023, FDA lists GHRP-6 as a substance that may present significant safety risks. It cites possible immune reactions from clumping and impurities, a potential effect on cortisol, and higher blood sugar from reduced insulin sensitivity.[15]
- Traditional pharmacies (503A): FDA’s May 14, 2026 list puts GHRP-6 in category 3, substances nominated without adequate support.[16]
Our peptide calculator converts milligrams into syringe units, but it cannot tell you whether a dose is safe or what a vial actually contains. A clinician should decide whether any growth hormone-related treatment is appropriate and set the dose.
Questions to ask a clinician
- Do I have symptoms or lab results that suggest a growth hormone problem, and how would we test for it?
- Which approved treatments fit my situation, if any?
- Do I have diabetes, prediabetes or a pituitary or adrenal condition that GHRP-6 could affect?
- If I have used GHRP-6, which blood tests should we check?
This is general information, not medical advice.
