Research peptides

GHRP-2 Dosage: Common Protocol, Study Doses and Calculator

GHRP-2 has no FDA-approved product to dose from. Here are the doses used in the published diagnostic-test and repeated-dosing studies, and what is not established.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published September 27, 2026Updated September 28, 2026

The short version

GHRP-2 has no FDA-approved product, so there is no approved dose. Community and vendor dosing guides most often describe 100-300 mcg by subcutaneous injection, 2 to 3 times daily on an empty stomach, 5 days a week. The cycle is 8 weeks with a 4-week break. That is common practice, not trial-established. The best-known human studies used a single, monitored diagnostic injection instead: a fixed 100-microgram intravenous dose in adults, or 2 micrograms per kilogram in children. The repeated regimens I verified were small studies in children with growth hormone deficiency and in critically ill patients.

Common practice is 100-300 mcg subcutaneous, 2-3 times daily, 5 days a week (5 on, 2 off), in an 8-week cycle with a 4-week break. It is not trial-established.
The diagnostic-test doses were 100 mcg fixed IV in adults and 2 mcg/kg IV in children, each given once.
Those studies tested pituitary function in a clinic in one sitting, not a repeated take-home protocol.
The repeated human regimens I verified were small studies in children with growth hormone deficiency and in critically ill patients.

GHRP-2 has no approved treatment dose, because it has no approved treatment product. It is reported to be the only GHRP to have received clinical approval (Popławska 2019 - Popławska M, Błażewicz A. Identification of a novel growth hormone releasing peptide (a glycine analogue of GHRP-2) in a seized injection vial. Drug Test Anal. 2019;11(1):162-167., in the references below), and that approval, in Japan, is as a one-off diagnostic test. This page reports what published human studies and one animal study used, not a recommendation for what anyone should take. For legal status, FDA’s compounding safety flag and the WADA ban, see the main GHRP-2 guide.

US legal status - Research use only

GHRP-2 has no FDA-approved product and no approved dose. FDA lists it in Category 2 of its interim compounding-safety policy.

AU legal status - Not on the ARTG

Named explicitly in the Poisons Standard (Appendix D) as a substance that must not be possessed without authority.

Regulators reach their own conclusions on their own timelines. Where these two disagree, the difference is the point - not an error.

GHRP-2 dosage: the common protocol

Community and vendor dosing guides most often describe 100-300 mcg by subcutaneous injection, 2 to 3 times daily on an empty stomach. The schedule is 5 days a week (5 days on, 2 days off). The cycle is 8 weeks with a 4-week break. This is common practice, not a dose any trial or regulator has established.

Common protocol

What is commonly used, not a dose established in trials. No regulator has set a dose for GHRP-2.

Dose per administration: 100-300 mcg
How often: 2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off)
Route: Subcutaneous injection
Cycle length: 8 weeks
Break between cycles: 4 weeks
Common vial size: 5 mg
Timing: Fasted - roughly 30-90 minutes before injection and 30 minutes after - commonly morning and before bed.
Commonly paired with: CJC-1295

Guides describe co-injecting with CJC-1295 (no-DAC) at 100 mcg in the same syringe for a larger combined GH pulse; doses above roughly 300 mcg per injection are described as giving diminishing GH return while raising cortisol and prolactin. Source upgrade pass (2026-09-27): added a real published human trial (Oxford/JCEM, an 8-month graded-dose study of subcutaneous GHRP-2 in GH-deficient children) confirming that repeated SC GHRP-2 dosing has genuine clinical pharmacology behind it. That trial dosed by body weight (0.3, 1.0, then 3.0 mcg/kg/day across successive 2-month blocks) in a pediatric GH-deficiency population, which is not directly comparable to the flat adult mcg convention self-administration guides describe, so it was kept as a third, corroborating source rather than used to rewrite the flat dose range - the Peptide Schedule source was not dropped because it is still the only one giving the 5mg-vial/8-week-cycle specifics.

Plan a cycle in the protocol builder or work out injection volume in the dosage calculator.

The common GHRP-2 dose is 100-300 mcg, 2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off). From a 5 mg vial mixed with 2 mL of bacteriostatic water, 200 mcg is 8 units (0.08 mL) on a U-100 insulin syringe.

GHRP-2 5 mg vial: units per dose

Full 5 mg vial page: mixing, doses per vial, how long it lasts →

Water added	Concentration	1 unit =	100 mcg	200 mcg	300 mcg
1 mL	5 mg/mL	50 mcg	2 units	4 units	6 units
2 mL	2.5 mg/mL	25 mcg	4 units	8 units	12 units
3 mL	1.67 mg/mL	16.67 mcg	6 units	12 units	18 units

All GHRP-2 vial sizes: 5 mg · 10 mg

Units are on a standard U-100 insulin syringe (100 units = 1 mL), rounded to the nearest half unit - half-unit marks are on 0.3 mL syringes. Water volumes are examples: more water means more units per dose, not more doses per vial. For any other vial or dose, use the calculator below.

How many 5 mg vials a cycle takes

Scenario	Dose	Doses a week	Weeks	Total	5 mg vials
Low end of the common protocol	100 mcg	10	8	8 mg	2
High end of the common protocol	300 mcg	15	8	36 mg	8

Whole vials, rounded up. Plan a cycle with your own numbers in the protocol builder. Keep mixed vials cold and use them within the window in how long reconstituted peptides last; where to inject: subcutaneous injection sites.

GHRP-2 doses used in human studies

The three diagnostic and detection studies gave GHRP-2 as a single, clinic-monitored intravenous injection. They tested how much growth hormone the pituitary released over the next one to two hours. This was a diagnostic procedure, not a repeated protocol.

Study	Population	Route	Dose	Course
Adult GH-deficiency diagnostic test Chihara 2007 - Chihara K, Shimatsu A, Hizuka N et al. A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol. 2007;157(1):19-27., in the references below	77 healthy adults, 58 patients with confirmed growth hormone deficiency	Intravenous, after overnight fasting	100 mcg fixed dose	Single injection
Paediatric diagnostic test Asakura 2010 - Asakura Y, Toyota Y, Muroya K et al. Growth hormone response to GH-releasing peptide-2 in children. J Pediatr Endocrinol Metab. 2010;23(5):473-80., in the references below	56 children being evaluated for growth disorders	Intravenous	2 mcg/kg body weight	Single injection
Doping-detection study Okano 2010 - Okano M, Nishitani Y, Sato M et al. Influence of intravenous administration of growth hormone releasing peptide-2 (GHRP-2) on detection of growth hormone doping: growth hormone isoform profiles in Japanese male subjects. Drug Test Anal. 2010;2(11-12):548-56., in the references below	10 healthy Japanese men	Intravenous	100 mcg fixed dose	Single injection

Adults: serum GH peaked within 60 minutes in every subject. Peak concentrations averaged 84.6 mcg/l in healthy adults versus 1.36 mcg/l in confirmed GHD patients. This is the basis for a proposed 15 mcg/l cut-off used to diagnose deficiency (Chihara 2007 - Chihara K, Shimatsu A, Hizuka N et al. A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol. 2007;157(1):19-27., in the references below).
Children: the paediatric study found the same pattern and cut-off, correlating well with the older insulin tolerance test (Asakura 2010 - Asakura Y, Toyota Y, Muroya K et al. Growth hormone response to GH-releasing peptide-2 in children. J Pediatr Endocrinol Metab. 2010;23(5):473-80., in the references below).
Doping detection: the study used the identical 100-microgram dose in healthy men purely to characterise how GHRP-2 affects a separate anti-doping immunoassay, not to test any treatment benefit (Okano 2010 - Okano M, Nishitani Y, Sato M et al. Influence of intravenous administration of growth hormone releasing peptide-2 (GHRP-2) on detection of growth hormone doping: growth hormone isoform profiles in Japanese male subjects. Drug Test Anal. 2010;2(11-12):548-56., in the references below).

Repeated dosing in humans

The repeated regimens I verified were small and supervised, and the people had a diagnosed condition. None were healthy adults.

Study	Population	Route	Dose	Course
Growth study Mericq 1998 - Mericq V, Cassorla F, Salazar T et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. J Clin Endocrinol Metab. 1998;83(7):2355-60., in the references below	6 prepubertal children with growth hormone deficiency	Subcutaneous	0.3, then 1.0, then 3.0 mcg/kg/day	2 months at each dose, then 2 months of 3 mcg/kg with GHRH
Appetite and weight study Mericq 2003 - Mericq V, Cassorla F, Bowers CY et al. Changes in appetite and body weight in response to long-term oral administration of the ghrelin agonist GHRP-2 in growth hormone deficient children. J Pediatr Endocrinol Metab. 2003;16(7):981-5., in the references below	10 prepubertal children with growth hormone deficiency	By mouth	900 mcg/kg twice daily	12 months
Critical illness study Van 1999 - Van den Berghe G, Wouters P, Weekers F et al. Reactivation of pituitary hormone release and metabolic improvement by infusion of growth hormone-releasing peptide and thyrotropin-releasing hormone in patients with protracted critical illness. J Clin Endocrinol Metab. 1999;84(4):1311-23., in the references below	14 patients with protracted critical illness	Infusion, with TRH	1 mcg/kg per hour	5 days, and 5 days of placebo, in random order

Growth study (8 months in all): overnight growth hormone rose with dose. Growth velocity was higher during treatment than before or after it, but IGF-I did not rise. The investigators observed no side effects or toxicities (Mericq 1998 - Mericq V, Cassorla F, Salazar T et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. J Clin Endocrinol Metab. 1998;83(7):2355-60., in the references below).
Oral study: 7 of 10 children reported a significant increase in appetite during the first 6 months (Mericq 2003 - Mericq V, Cassorla F, Bowers CY et al. Changes in appetite and body weight in response to long-term oral administration of the ghrelin agonist GHRP-2 in growth hormone deficient children. J Pediatr Endocrinol Metab. 2003;16(7):981-5., in the references below).
Critical illness study: IGF-I reached near-normal levels from day 2 (Van 1999 - Van den Berghe G, Wouters P, Weekers F et al. Reactivation of pituitary hormone release and metabolic improvement by infusion of growth hormone-releasing peptide and thyrotropin-releasing hormone in patients with protracted critical illness. J Clin Endocrinol Metab. 1999;84(4):1311-23., in the references below).

Doses used in animal studies

A swine study (Phung 2000 - Phung LT, Inoue H, Nou V et al. The effects of growth hormone-releasing peptide-2 (GHRP-2) on the release of growth hormone and growth performance in swine. Domest Anim Endocrinol. 2000;18(3):279-91., in the references below) first compared single intravenous doses of 2, 10, 30 and 100 mcg/kg body weight in cross-bred castrated male pigs and found a dose-dependent GH response. It then gave 30 mcg/kg once daily by subcutaneous injection for 30 days to measure growth performance. Compared with saline controls, average daily weight gain rose 22.35% and feed efficiency improved 20.64%. The GH response was partly attenuated between day 1 and day 10 of treatment.

What is not established

No approved treatment dose exists, for any population, indication, route or duration. No product has completed FDA review, and the only approval, in Japan, is as a one-off diagnostic test.
No repeated dosing schedule for healthy adults is established. The repeated regimens above were in children with growth hormone deficiency and critically ill patients, under medical supervision. The diagnostic studies gave a single clinic-administered injection.
No adult half-life is established. The one pharmacokinetic study I verified gave 10 children with short stature a single 1 mcg/kg intravenous dose. It found an elimination half-life of about 0.55 hours, roughly 33 minutes (Pihoker 1998 - Pihoker C, Kearns GL, French D et al. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in children. J Clin Endocrinol Metab. 1998;83(4):1168-72., in the references below). It does not establish an interval for repeated subcutaneous dosing in adults.
The common protocol above comes from community and vendor dosing guides, not from any study, paper or regulator. It is current common practice, not a trial finding.

How to reconstitute GHRP-2

Turning a target amount into an injection volume depends on how a specific vial was reconstituted: how much diluent, and what resulting concentration. This page cannot know that for your vial. The dosage calculator walks through vial strength, diluent volume and target amount. It performs the math; it does not tell you what dose to use.

Who should not use it

No FDA-reviewed contraindication list exists, because GHRP-2 has never gone through that review. The diagnostic studies above monitored otherwise healthy or well-characterised patients for one to two hours in a clinic. None establishes safety for repeated self-administration outside that setting.

FDA’s Category 2 compounding-safety listing for GHRP-2 cites reports of increased insulin requirements, death in critically ill subjects, infection and pancreatitis. Anyone critically ill, diabetic, pregnant, breastfeeding, or with any diagnosed medical condition has no basis for self-directed use.

GHRP-2 side effects and risks

The main verified risks are the ones FDA lists in its Category 2 compounding-safety flag. They are possible immunogenicity from aggregation and peptide-related impurities, plus reports of increased insulin requirements, death in critically ill subjects, infection and pancreatitis. Beyond that flag:

There is no long-term safety study in adults at any dose.
There is no adult half-life after subcutaneous injection.
Material sold as a research chemical carries no regulator-verified purity, identity or concentration.

GHRP-2 is also prohibited at all times in sport under the WADA Prohibited List. See the main guide for that listing.

GHRP-2 dosage calculator

Preset to a 5 mg vial and 100 mcg, the low end of the common protocol. Enter your own vial size, water and dose to get the syringe units to draw.

Your vial

Peptide in vial (mg)

Printed on the vial. There is no standard size - enter what yours says.

Bacteriostatic water added (mL)

This changes how much you draw - never how many doses the vial holds.

Desired dose (mcg)

Syringe scale

100 units per mL. 1 unit = 0.01 mL. This is what almost every insulin syringe sold is, in every barrel size.

Barrel size

Capacity only. A 1 mL U-100 syringe holds 100 units - the scale decides that, not the barrel.

Draw this much

4units

= 0.04 mL on a 1 mL U-100 syringe

Concentration: 2,500 mcg/mL
Exact volume: 0.04 mL
Dose you actually get: 100 mcg
Doses per vial(unaffected by water volume): 50

Where to buy GHRP-2 for research

Each vendor is checked against my vendor checklist.

1.Next Level PharmFeatured
5 mg vial
- No FDA warning letter found
- Names its testing lab
- Batch COAs published
- Takes card payment
$39.99as of 3 October 2026
View product →My Next Level Pharm review

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Common questions

What is the usual GHRP-2 dose?

Community and vendor dosing guides most often describe 100-300 mcg by subcutaneous injection, 2 to 3 times a day on an empty stomach. The schedule is 5 days a week (5 days on, 2 days off). It is often paired with CJC-1295 in the same injection. The cycle is 8 weeks with a 4-week break. That is common practice, not a dose established by any human trial. The published diagnostic studies used a single monitored injection (see the next question).

What is the GHRP-2 dosage used in human studies?

The diagnostic studies each used a single, clinic-administered intravenous dose to test pituitary growth hormone release, not a repeated take-home protocol. In adults, a study of 77 healthy subjects and 58 patients with confirmed growth hormone deficiency used a fixed 100-microgram intravenous dose after an overnight fast. In 56 children being evaluated for growth disorders, a separate study used 2 micrograms per kilogram of body weight, also intravenously. A third study gave 100 micrograms intravenously to 10 healthy Japanese men in an anti-doping detection context. The repeated regimens I verified were small. Six children with growth hormone deficiency had daily subcutaneous injections rising from 0.3 to 3 micrograms per kilogram over 6 months. Ten such children had 900 micrograms per kilogram by mouth twice daily for a year. Fourteen critically ill patients had a 5-day infusion together with TRH.

Is there an FDA-approved GHRP-2 dose?

No. GHRP-2 has no FDA-approved product. Its only approval, in Japan, is as a single-dose diagnostic test of growth hormone release, not a treatment, so no regulator has approved a treatment or repeated dose. The figures on this page are what studies gave their own participants under monitoring, not a recommendation.

What dose was used in animal studies?

A swine study gave GHRP-2 by single intravenous injection at 2, 10, 30 or 100 micrograms per kilogram to compare dose-response. It then gave 30 micrograms per kilogram once daily by subcutaneous injection for 30 days to measure growth performance. That is a pig dose in a farm-growth model. There is no accepted method for converting it into a human dose, and the study was not designed to test safety.

Can I use the diagnostic-test dose as a repeated protocol?

No study I found tested that. The 100-microgram and 2-microgram-per-kilogram doses were each given once, in a clinic, to trigger a short-lived pituitary response that researchers measured over the following two hours. No published human study repeated either dose daily or weekly. The repeated regimens I verified were in children with growth hormone deficiency and critically ill patients, under medical supervision. There is no evidence-based schedule to report for ongoing self-administered use.

How do I work out reconstitution and injection volume?

That is arithmetic about a specific vial and diluent, not a dosing decision, and this page cannot know your vial. Use the dosage calculator to work out concentration and draw volume for whatever amount you are looking at. It does the math; it does not tell you what dose to use.

Who should not use GHRP-2?

No FDA-reviewed contraindication list exists, because GHRP-2 has never gone through that review. FDA has separately flagged GHRP-2 for injectable and nasal compounding as a Category 2 safety risk. It cites reports of increased insulin requirements, death in critically ill subjects, infection and pancreatitis. Anyone critically ill, diabetic, pregnant, or with any diagnosed condition has no regulator-reviewed information to weigh a decision against.

When should I stop and get medical care?

Get emergency care (call 911 in the US) for a severe allergic reaction, chest pain, fainting, or any symptom that feels dangerous. Call Poison Control at 1-800-222-1222 if you have taken an unknown or excessive amount of anything sold as GHRP-2. This is not a substitute for a clinician who knows your history.

References (9 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.