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Research use only · common protocol

GHRP-2 5 mg vial dosage

A 5 mg GHRP-2 vial mixed with 1.5 mL of bacteriostatic water gives 3.33 mg/mL, so 200 mcg is 6 units (0.06 mL) on a U-100 insulin syringe. At 200 mcg a dose, one vial holds 25 doses.

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The common GHRP-2 protocol is 100-300 mcg, 2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off) - common practice, not a dose established in trials. Evidence, side effects and legal status are on the full GHRP-2 dosing page.

GHRP-2 5 mg vial at a glance

Vial
5 mg of GHRP-2 per vial
Common dose
100-300 mcg
How often
2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off)
Mixing example
1.5 mL bacteriostatic water = 3.33 mg/mL; 1 unit = 33.33 mcg
Doses per vial
50 at 100 mcg · 25 at 200 mcg · 16 at 300 mcg
Cycle
8 weeks, then 4 weeks off

What GHRP-2 is

Class:
Synthetic hexapeptide, one of the growth hormone releasing peptides (GHRPs)
Also called:
Growth Hormone Releasing Peptide-2, Pralmorelin, KP-102, GPA-748, GHRP Kaken 100
Used for:
Sold to consumers as a growth-hormone-release research chemical for muscle and recovery use, an application never approved anywhere. Historically investigated as a pituitary growth-hormone stimulus and diagnostic agent.
Human evidence:
Limited human data. The human literature goes back to the 1990s and is mostly single-dose diagnostic testing: a 100 mcg intravenous dose separated healthy adults from patients with growth hormone deficiency, and a 2 mcg/kg dose worked as a test in children. The other studies I verified are small - increased food intake in healthy adults, 8 months of daily injections in 6 children with growth hormone deficiency, and a 5-day infusion with TRH in 14 critically ill patients. None of them measured muscle, strength or body composition in healthy adults. FDA lists GHRP-2 in Category 2 of its interim compounding policy, and WADA names GHRP-2 (pralmorelin) explicitly as a prohibited GH-releasing peptide.
Half-life:
About 0.55 hours (roughly 33 minutes) elimination half-life after a single 1 mcg/kg intravenous dose, in one phase I study of 10 children with short stature. No adult half-life after subcutaneous injection was found.
US status:
Research use only. Not FDA-approved for any indication in the US; a DailyMed search for GHRP-2 returns zero drug labels. Outside the US it is reported to be the only GHRP to have received clinical approval, and Japan lists pralmorelin hydrochloride as a diagnostic agent for endocrine function testing, not a treatment. FDA lists "Growth hormone releasing peptide-2 (GHRP-2) (for injectable and nasal routes of administration)" in Category 2 of its interim bulk drug substance compounding policy (503B, added 29 September 2023) - substances for which the agency identified potential significant safety risks - and GHRP-2 remains in that table, not among substances withdrawn from it. Sold as a research chemical and not legally marketed for human use. Named explicitly as "GHRP-2 (pralmorelin)" in the WADA 2026 Prohibited List under S2.2, among GH-releasing peptides (GHRPs), prohibited at all times. Australia's Poisons Standard (Appendix D, clause 5) also names "pralmorelin (GHRP-2)" explicitly, alongside the broader GHRP class; nothing containing it has been verified on the ARTG.

The full picture, with every study: GHRP-2 guide.

Units per dose: GHRP-2 5 mg vial

Water addedConcentration1 unit =100 mcg200 mcg300 mcg
1.5 mL3.33 mg/mL33.33 mcg3 units6 units9 units
3 mL1.67 mg/mL16.67 mcg6 units12 units18 units
5 mL1 mg/mL10 mcg10 units20 units30 units

U-100 insulin syringe (100 units = 1 mL), to the nearest half unit. Water volumes are examples. Other numbers: dosage calculator.

Every dose from 100 mcg to 300 mcg, in units

With 1.5 mL of water in a 5 mg vial (3.33 mg/mL). Every dose across the common range, so you can read off any dose. The sources give a range, not a week-by-week schedule.

DoseDraw on a U-100 syringeVolumeDoses per vial
100 mcg3 units0.03 mL50
125 mcg4 units0.04 mL40
150 mcg4.5 units0.045 mL33
175 mcg5.5 units0.055 mL28
200 mcg6 units0.06 mL25
225 mcg7 units0.07 mL22
250 mcg7.5 units0.075 mL20
275 mcg8.5 units0.085 mL18
300 mcg9 units0.09 mL16

How many doses a 5 mg vial holds

DoseDoses per vialWeeks per vial
100 mcg503.3-5
200 mcg251.7-2.5
300 mcg161.1-1.6

Weeks per vial at the common frequency (2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off)). Doses per vial do not depend on how much water you add.

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The common GHRP-2 protocol

Dose100-300 mcg per injection
How often2 to 3 times daily, on an empty stomach, 5 days a week (5 on, 2 off)
TimingFasted - roughly 30-90 minutes before injection and 30 minutes after - commonly morning and before bed.
RouteSubcutaneous injection
Cycle8 weeks
Break4 weeks
Often paired withCJC-1295
Sources agree?Yes, the sources give the same protocol

Common practice from the vendors and clinics that publish it, not a dose tested in trials. Where it comes from: [1], [2], [3]. I do not give week-by-week titration: none of these sources states one.

Supplies for one cycle with 5 mg vials

Counted for the low and high ends of the common protocol, mixing each vial with 1.5 mL of water. One new syringe per injection.

PlanInjections5 mg vialsInsulin syringesBacteriostatic waterAlcohol swabs
100 mcg, 10×/week, 8 weeks802803 mL (1 × 10 mL bottle)164 (2 × 100-pack)
300 mcg, 15×/week, 8 weeks120812012 mL (2 × 10 mL bottles)256 (3 × 100-pack)

Arithmetic on the protocol and this vial size. Swabs: two per vial mixed (both stoppers) and two per injection (vial stopper and skin). An opened multi-dose vial has a use-by date (see storage), which on a slow schedule can matter more than the dose count. Plan your own numbers with the protocol builder.

How to mix a 5 mg GHRP-2 vial

For this vial: 1.5 mL of bacteriostatic water makes 3.33 mg/mL, so 200 mcg is 6 units (0.06 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

  1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. [4][5]
  2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. [4][5][6]
  3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. [7]
  4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. [4][5][7]
  5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. [4]
  6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. [7]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing GHRP-2 vials

  • Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. [8]
  • Protect peptide vials from heat and light. [8][9]
  • Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. [7][8]
  • Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. [10][11]

More detail: peptide storage and shelf life.

Injecting safely

  • Clean the injection site with an alcohol swab and let the skin dry completely before injecting. [12][13]
  • Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. [12][13][14]
  • Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. [12]
  • Inject slowly, at roughly 10 seconds per mL. [12]
  • Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. [7][12][13]

Hygiene and warning signs

  • Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. [6][10][13]
  • Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. [6][9][10]
  • Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. [15][16]
  • Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. [13]

Where to inject: subcutaneous injection sites.

How GHRP-2 works

  • GHRP-2 (pralmorelin) is a synthetic, non-natural peptide described as a 'super-analogue' of GHRP-6 with a potent growth hormone-releasing effect. Of the GHRPs developed as drug candidates, it is reported to be the only one to have received clinical approval. [17][18]
  • It is a synthetic agonist of the receptor used by ghrelin, the gut hormone that stimulates both growth hormone release and appetite. [19]
  • Its growth hormone-releasing effect appears to need the body's own GHRH. In mice lacking GHRH, 6 weeks of GHRP-2 failed to raise growth hormone or growth, and a single dose released growth hormone only when given together with a GHRH analogue. [20][21]
  • In 10 children with short stature given 1 mcg/kg intravenously, GHRP-2 had an elimination half-life of about 0.55 hours (roughly 33 minutes). [22]

What the GHRP-2 research found

Human evidence: limited human data. Each result says what was studied.

  • Human studyIn a study of 77 healthy adults and 58 patients with growth hormone deficiency confirmed by insulin tolerance test, a single 100 mcg intravenous dose of GHRP-2 gave a mean peak growth hormone of 84.6 mcg/l in healthy people against 1.36 mcg/l in patients. The authors proposed it as a diagnostic test with a 15 mcg/l cut-off. [23]
  • Human studyIn 7 lean healthy men, a 270-minute subcutaneous infusion of GHRP-2 increased the amount eaten at a buffet meal by 35.9% compared with saline, and every participant ate more. [19]
  • Human studyIn a double-blind randomised study of 19 healthy adults (10 lean, 9 obese), GHRP-2 infusion raised food intake with dose, by 10.2% at the low dose and 33.5% at the high dose. Obesity did not change the response. [24]
  • Human studyIn 6 children with growth hormone deficiency given rising daily subcutaneous doses over 6 months, then GHRP-2 with GHRH for 2 more months, overnight growth hormone increased with GHRP-2 dose but IGF-I and IGFBP-3 did not rise. Growth velocity was higher during treatment than before or after it. [25]
  • Human studyIn 14 patients with protracted critical illness, 5 days of GHRP-2 infused together with TRH, compared with 5 days of placebo in random order, raised IGF-I to near-normal levels and increased osteocalcin by 19% (against a 6% fall on placebo), without changing cortisol. [26]
  • Animal studyIn pigs, once-daily subcutaneous GHRP-2 for 30 days kept stimulating growth hormone release, though the response weakened between days 1 and 10. Average daily weight gain rose by 22%. [27]

GHRP-2 side effects and risks

No trial has published systematic safety data for repeated self-injected GHRP-2 in adults.

  • Regulator reviewFDA lists GHRP-2 (injectable and nasal) in category 2 of its compounding policy. It cites reports of serious adverse events in people who received GHRP-2, including increased insulin requirements, death of critically ill study subjects, infection and pancreatitis, while noting that causality has not been established. [28]
  • Human studyGHRP-2 is not fully selective for growth hormone. In 6 healthy young adults it also raised prolactin, ACTH and cortisol, with an ACTH and cortisol response similar to that produced by corticotropin-releasing hormone. [17]
  • Human studyIncreased appetite is documented. In 10 children with growth hormone deficiency taking oral GHRP-2 for 12 months, 7 reported a significant increase in appetite during the first 6 months, though BMI did not change significantly. [29]
  • Human studyIn the 8-month study of 6 children given subcutaneous GHRP-2, the investigators observed no side effects or toxicities. [25]

Other things to know

  • FDA states that compounded drugs containing GHRP-2 for injectable or nasal administration may pose a risk for immunogenicity from aggregation and peptide-related impurities, and cites reports of serious adverse events including increased insulin requirements, death in critically ill subjects, infection and pancreatitis.
  • Never approved by the FDA for any indication. Its only approval, in Japan, is as a one-off diagnostic test of growth hormone release, not a treatment.
  • Short-acting: the one verified human half-life is about 33 minutes, after a single intravenous dose in children. No adult half-life after subcutaneous injection was found.
  • Not selective for growth hormone: in human studies it also raised prolactin, ACTH and cortisol, and it increases appetite.
  • Prohibited at all times in sport, named explicitly as GHRP-2 (pralmorelin) in the WADA 2026 Prohibited List.
  • Sold as a research chemical labelled not for human use, so identity, purity and dose are unverified.

Reported side effects and what the studies measured: GHRP-2 side effects.

Where this vial size comes from

GHRP-2 is sold as a 5 mg vial by the page below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

  • SwissChemsvendorLists it as: "GHRP-2 5mg (1 vial)" · checked 2026-09-28

The doses come from the sourced common protocol on the GHRP-2 dosing page, and every number on this page is arithmetic on those doses and this vial size.

Other GHRP-2 vial sizes

Where to buy GHRP-2 for research

Sold for research use only. Listed by Next Level Pharm; compare them on my vendors page or see the listing on the GHRP-2 page.

Questions

How much water do I add to a 5 mg GHRP-2 vial?
There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1.5 mL the vial is 3.33 mg/mL and 200 mcg is 6 units (0.06 mL) on a U-100 insulin syringe. The units table gives 1.5, 3, 5 mL.
How many doses are in a 5 mg GHRP-2 vial?
50 doses at 100 mcg, 25 doses at 200 mcg, 16 doses at 300 mcg.
How long does a 5 mg GHRP-2 vial last?
At 200 mcg a dose and 2 to 3 times daily, about 1.7-2.5 weeks. How long a mixed vial keeps is a separate limit; see storage below.
How many 5 mg vials do I need for a cycle?
2 vials at 100 mcg 10 times a week for 8 weeks; 8 vials at 300 mcg 15 times a week for 8 weeks.
What does 1 unit equal in a 5 mg GHRP-2 vial?
33.33 mcg with 1.5 mL, 16.67 mcg with 3 mL, 10 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.

References (31 sources)

  1. [1] Peptide Schedule: 100-200 mcg per injection, 2-3x daily, 5 days on/2 off, 8 weeks on/4 weeks off, 5mg vial in 2mL BAC water, co-inject with CJC-1295 no-DAC (other, checked 2026-09-27)
  2. [2] Form Blends: 100 mcg per injection, 2-3x/day (200-300 mcg/day total), subcutaneous, diminishing returns above ~300 mcg, pairs with a GHRH analog like CJC-1295 (vendor, checked 2026-09-27)
  3. [3] The Journal of Clinical Endocrinology & Metabolism (Oxford Academic): Eight-month human trial of subcutaneous GHRP-2 in prepubertal GH-deficient children, graded doses of 0.3, 1.0 and 3.0 mcg/kg/day across successive 2-month treatment periods - real published human dosing data for repeated SC GHRP-2 use, though weight-based and pediatric rather than the flat adult mcg convention used elsewhere in this record (publication, checked 2026-09-27)
  4. [4] OpenStax, Rice University: 12.3 Preparing Unit-Dose Packaged Medications - Clinical Nursing Skills
  5. [5] East Carolina University College of Nursing: Reconstitution of Medication
  6. [6] Centers for Disease Control and Prevention: Considerations for Blood Glucose Monitoring and Insulin Administration
  7. [7] DailyMed, National Library of Medicine: SEROSTIM (somatropin) for injection - prescribing information and instructions for use
  8. [8] GenScript: Peptide Storage and Handling Guidelines
  9. [9] DailyMed, National Library of Medicine: OZEMPIC (semaglutide) injection - prescribing information
  10. [10] Centers for Disease Control and Prevention: Preventing Unsafe Injection Practices
  11. [11] Pfizer: Bacteriostatic Water for Injection, USP - prescribing information
  12. [12] OpenStax, Rice University: 12.5 Administering Subcutaneous Injections - Clinical Nursing Skills
  13. [13] MedlinePlus, National Library of Medicine: Subcutaneous (SQ) injections
  14. [14] Centers for Disease Control and Prevention: Chapter 6: Vaccine Administration - Pink Book
  15. [15] US Food and Drug Administration: Best Way to Get Rid of Used Needles and Other Sharps
  16. [16] US Food and Drug Administration: DOs and DON'Ts of Proper Sharps Disposal
  17. [17] Arvat E, di Vito L, Maccagno B et al. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH. Peptides. 1997;18(6):885-91.
  18. [18] 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.
  19. [19] Laferrère B, Abraham C, Russell CD et al. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. 2005;90(2):611-4.
  20. [20] Alba M, Fintini D, Bowers CY et al. Effects of long-term treatment with growth hormone-releasing peptide-2 in the GHRH knockout mouse. Am J Physiol Endocrinol Metab. 2005;289(5):E762-7.
  21. [21] Fintini D, Alba M, Schally AV et al. Effects of combined long-term treatment with a growth hormone-releasing hormone analogue and a growth hormone secretagogue in the growth hormone-releasing hormone knock out mouse. Neuroendocrinology. 2005;82(3-4):198-207.
  22. [22] 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.
  23. [23] 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.
  24. [24] Laferrère B, Hart AB, Bowers CY. Obese subjects respond to the stimulatory effect of the ghrelin agonist growth hormone-releasing peptide-2 on food intake. Obesity (Silver Spring). 2006;14(6):1056-63.
  25. [25] 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.
  26. [26] 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.
  27. [27] 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.
  28. [28] US Food and Drug Administration: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (category 2 table, GHRP-2 for injectable and nasal routes, 503B; content current as of 22 April 2026)
  29. [29] 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.
  30. [30] 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.
  31. [31] 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.