GHRP-2

Dosing from the Literature

Published for growth hormone: one IV test dose (100 mcg in adults, 2 mcg/kg in children; the approved Japanese test), single IV doses of 1–2 mcg/kg in research, and repeated doses in trials lasting 5 days to 2 years. Not published: any trial of the two or three daily injections online protocols describe.

The rows below give the dose on the Japanese label, the doses of published studies, and what clinic records and online protocols describe; the last column names each row's source. Not medical advice. No FDA-approved dose exists.

What It Is

GHRP-2 (Growth Hormone-Releasing Peptide-2; INN pralmorelin; developmental codes KP-102, GPA-748, WAY-GPA-748) is a synthetic hexapeptide (a chain of 6 amino acids) growth hormone secretagogue with the sequence D-Ala-D-(β-naphthyl)-Ala-Trp-D-Phe-Lys-NH2 and a molecular weight of 817.97 g/mol. It is the second-generation member of the GHRP (a synthetic GH trigger) family, developed by structure-activity-relationship optimization of the parent GHRP-6. Substituting D-2-naphthylalanine at position 2 produced substantially enhanced GH-releasing potency per molecule and reduced the prominent appetite-stimulating signal characteristic of GHRP-6.

GHRP-2 is the most clinically advanced of the classical first-generation hexapeptide GH secretagogues. It received approval from Japan's Pharmaceuticals and Medical Devices Agency (PMDA) in October 2004 and is marketed by Kaken Pharmaceutical under the brand name GHRP Kaken 100 as a single-dose intravenous diagnostic agent for the assessment of growth hormone deficiency (GHD) in adults and children aged 4 and over (GHRP Kaken 100 label, 2025). The approval rests on Japanese trials in which one IV dose (100 mcg, or 2 mcg/kg or more) gave a peak GH of 15.9–345.1 ng/mL (mean 84.6) in 89 healthy people, including children of normal short stature, while 100 mcg gave at most 14.8 ng/mL (mean 1.37) in 60 patients with severe GH deficiency; the label sets the cutoff for severe deficiency at 15 ng/mL (GHRP Kaken 100 label, 2025). This makes GHRP-2 unique among the GHRPs — and unique among the peptides commonly discussed in the optimization community — as a compound with active regulatory approval in a major pharmaceutical market for a defined diagnostic indication.

That regulatory approval is for diagnostic use only — a single IV dose (100 mcg in adults, 2 mcg/kg in children) to evaluate pituitary GH secretory capacity (GHRP Kaken 100 label, 2025). GHRP-2 was tested in children with short stature: in 15 children, intranasal GHRP-2 at 5–15 µg/kg, twice and then three times a day, raised height velocity from 3.7 to 6.1 cm/year at six months and 6.0 cm/year in the six followed for 18–24 months, with no significant change in IGF-1 or IGFBP-3 and none in the acute GH response; the authors call it a modest but significant increase (Pihoker et al. 1997, J Endocrinol). No GHRP-2 product was approved for the indication. Chronic SubQ multi-daily dosing for body composition, recovery, and "hyperphysiologic GH pulsing" — the use the optimization community pursues — is off-label everywhere, including in Japan, and operates on community convention rather than approved clinical evidence.

Compared to its sibling GHRP-6, GHRP-2 produces stronger peak GH release per unit dose, with notably less appetite stimulation and similar (modest) cortisol / prolactin elevation. Compared to ipamorelin — the modern selective GHS — it produces a larger GH peak but with a measurably less clean cortisol / prolactin profile. Among the classical hexapeptide GHRPs, GHRP-2 is more potent than GHRP-6 and less selective than ipamorelin; against hexarelin, at the same IV doses in six healthy young adults, it released similar amounts of GH, prolactin, ACTH and cortisol (Arvat et al., 1997).

Mechanism of Action

GHRP-2 is a synthetic agonist of the ghrelin receptor, GHS-R1a (Dominikowski et al., 2026; PMID 42395176). Its Japanese label describes it as releasing GH from the pituitary mainly through the hypothalamus (GHRP Kaken 100 label, 2025); in rats it also released GH directly from pituitary cells and needed the hypothalamus for its full effect (Doi et al., 2004; PMID 15646370).

• GHS-R1a agonism (primary mechanism) — GHRP-2 binds the GHS receptor (GHRP Kaken 100 label, 2025), GHS-R1a, a G-protein-coupled receptor found in the pituitary and in the arcuate, ventromedial and infundibular hypothalamus of pigs and humans (Howard et al., 1996; PMID 8688086). Its sequence differs from GHRP-6's at the first two positions: D-alanine for histidine, and D-2-naphthylalanine for D-tryptophan (Bowers et al., 1990; Doi et al., 2004).
• Appetite signal — Like ghrelin, GHRP-2 raises food intake: a 2026 review notes increases in healthy men and in people with obesity, comparable in size to ghrelin's (Dominikowski et al., 2026; PMID 42395176), and in rats it raised food intake in healthy controls but not in arthritic ones (Granado et al. 2005, Am J Physiol Endocrinol Metab).
• Synergy with GHRH — GHRPs act by a mechanism different from GHRH's (Mericq et al., 1998; PMID 9661608), and the first of them, GHRP-6, released GH synergistically with GHRH at low doses in 18 healthy men (Bowers et al., 1990; PMID 2108187). For GHRP-2 the results differ: given by IV injection with GHRH, it released more GH than the sum of the two in younger and older adults (Bowers et al., 2004; PMID 15126555), but no more than their sum in eight young men (Tiulpakov et al., 1995; PMID 7586605). GHRP-6 also needs the body's own GHRH: a GHRH antagonist removed about 80% of its GH response in nine healthy men (Pandya 1998, PMID 9543138).
• Less somatostatin-sensitive than GHRH — Doi et al. 2004 (PMID 15646370) found that in conscious rats KP-102 (GHRP-2) had stronger GH-releasing activity than exogenous GHRH, and that in conscious dogs it released GH where GHRH did not; the authors attribute this to lower sensitivity to the body's own somatostatin.
• Modest cortisol and prolactin elevation — In six healthy young adults, IV GHRP-2 (1 and 2 mcg/kg) raised prolactin, ACTH and cortisol as much as hexarelin did; the prolactin rise was smaller than TRH's and the ACTH and cortisol rise similar to CRH's (Arvat et al., 1997; PMID 9285939). In conscious rats it raised ACTH and corticosterone but not prolactin (Doi et al., 2004; PMID 15646370).
• CD36 binding (cytoprotection) — A 2017 review says two receptors, GHS-R1a and CD36, mediate the actions of GHRP-2, GHRP-6 and hexarelin on the heart, and describes GHRP-2 protecting heart and muscle cells in animal and cell studies (Berlanga-Acosta et al., 2017; PMID 28469491). In arthritic rats, GHRP-2 (100 mcg/kg a day for 8 days) lowered the arthritis score, paw swelling and IL-6; the authors attribute the effect to ghrelin receptors on immune cells (Granado et al. 2005, Am J Physiol Endocrinol Metab).
• Acts at both pituitary and hypothalamic sites — In rats, GHRP-2 released no GH once the pituitary was removed and less once the median eminence was destroyed, yet stimulated pituitary cells directly in culture (Doi et al., 2004; PMID 15646370); the general pharmacology paper describes it as acting at both sites (Furuta et al. 2004, PMID 15646371).
• Gut effects — In animal tests, GHRP-2 had negligible effects on the digestive system, apart from a slight, transient increase in the motility of isolated rabbit ileum and contraction of isolated guinea-pig ileum at high doses (Furuta et al. 2004, PMID 15646371). Its label lists stomach rumbling in 5% or more of people given the test dose (GHRP Kaken 100 label, 2025).
• What it does not do — It does not work without a pituitary: in rats without one it released no GH (Doi et al., 2004; PMID 15646370). It does not keep GH up: in GH-deficient children each injection's effect was brief, with little effect later in the night (Mericq et al., 1998; PMID 9661608). IGF-1 did not rise in children treated for months (Pihoker et al., 1997; Mericq et al., 1998; Tanaka et al., 2014) or in young men after 5 days of daily injections (Nijland et al., 1998; PMID 9820615), though it rose during a 30-day infusion in older adults (Bowers et al., 2004; PMID 15126555).

What the Research Shows

Japan approved GHRP-2 in 2004 as a one-dose diagnostic test for growth-hormone deficiency (GHRP Kaken 100 label, 2025); a 2026 review grades the rest of its human evidence as small studies of GH and appetite (Dominikowski et al., 2026). In a 48-week placebo-controlled trial in 126 children with GH deficiency, a twice-daily nasal spray did not improve growth (Tanaka et al., 2014).

• Foundational pharmacology (Bowers 1991, 1995) — GHRP-2 was synthesized and characterized by Bowers and colleagues during the structure-activity-relationship campaign that followed GHRP-6. Increased potency demonstrated in pituitary cell culture and in vivo in rats, dogs, and humans.
• Japanese diagnostic trials (Kaken, leading to the 2004 PMDA approval) — In 89 healthy people, including children of normal short stature, one IV dose (100 mcg, or 2 mcg/kg or more) gave a peak GH of 15.9–345.1 ng/mL; in 60 patients with severe GH deficiency, 100 mcg gave at most 14.8 ng/mL. The label sets the cutoff for severe deficiency at 15 ng/mL (GHRP Kaken 100 label, 2025).
• Doi et al. 2004 (PMID 15646370) — Pharmacological characterization in rats and dogs. KP-102 showed more potent GH release than GHRH in conscious rats; less somatostatin-sensitive; effective in conscious dogs where GHRH was not.
• Furuta et al. 2004 (PMID 15646371) — General pharmacology evaluation in animal models. Negligible effects on respiratory, cardiovascular, digestive, renal, and blood systems at doses producing GH-releasing activity. Safety basis for clinical advancement.
• Comparative human studies (Arvat, Bowers, Ghigo) — Multiple human studies comparing GHRP-2 with ghrelin, GHRP-6, hexarelin, and GHRH. GHRP-2 produces stronger GH peaks than GHRP-6 at equivalent doses, with similar or slightly less ACTH / cortisol elevation.
• Combined GHRH + GHRP-2 stimulation testing — In eight healthy young men, GHRH and GHRP-2 together (1 mcg/kg each, IV) released more GH than either alone, about the sum of the two (Tiulpakov et al., 1995). Japan's approved test uses GHRP-2 alone (GHRP Kaken 100 label, 2025).
• Therapeutic trials in children (short stature) — no approved product — GHRP-2 was evaluated for treatment of GH deficiency and short stature, as a nasal spray (Pihoker 1997, J Endocrinol) and by injection under the skin (Mericq 1998, J Clin Endocrinol Metab). GH secretion rose and growth velocity rose modestly (in Pihoker’s 15 children, from 3.7 to 6.1 cm a year at 6 months); IGF-1 did not. Therapeutic development was discontinued. In a later placebo-controlled trial in 126 Japanese children with GH deficiency, a nasal spray of 50–200 mcg twice a day for 48 weeks did not improve growth (Tanaka et al., 2014).
• Anti-inflammatory effects (Granado 2005) — Granado M et al. Anti-inflammatory effect of the ghrelin agonist GHRP-2 in arthritic rats. Am J Physiol Endocrinol Metab. 2005;288(3):E486-492. The authors attribute the effect to ghrelin receptors on immune cells.
• Pharmacokinetics — characterized for the diagnostic-dose route — In 18 healthy men given 0.3–3 mcg/kg IV, the elimination half-life was about 0.42–0.69 hours; after 100 mcg IV, about 2% of the dose left unchanged in the urine within 24 hours, and the label presumes it is cleared mainly in bile, as in rats and dogs (GHRP Kaken 100 label, 2025).
• Athletic doping detection — Multiple papers from Cuban and European laboratories (Thomas et al., Pozo et al., Cabrales et al.) establishing detection methods for GHRP-2 and metabolites in serum and urine. WADA-accredited laboratories routinely test for GHRP-2.

Human Data

GHRP-2 has the most extensive human data of any peptide in the GHRP family.

• Japanese diagnostic trials (Kaken) — 89 healthy people, including children of normal short stature, and 60 patients with severe GH deficiency, each given one IV dose: the trials behind the 2004 approval (GHRP Kaken 100 label, 2025).
• Healthy volunteer GH stimulation studies — In healthy young adults, 1–2 mcg/kg IV GHRP-2 released more GH than GHRH (Arvat et al., 1997); in eight young men given 1 mcg/kg, GH peaked 20–45 minutes after the dose (Tiulpakov et al., 1995).
• GHRH + GHRP-2 combined stimulation testing — Established as a sensitive test for adult GH deficiency. Multiple small clinical comparison studies vs ITT (insulin tolerance test).
• Phase II pediatric short-stature trials — negative — Intranasal GHRP-2 evaluated as therapeutic agent in children with short stature. Despite increasing endogenous GH secretion measurable in stim tests, clinical growth promotion was insufficient. Trials discontinued.
• Adult body-composition studies — modest signal — Several small open-label and uncontrolled studies have evaluated chronic SubQ GHRP-2 ± GHRH in older adults for body composition and recovery outcomes. Modest effects reported; no large RCT.
• HIV-associated wasting (older studies) — GHRP-2 was investigated for HIV-associated cachexia; some signal in early trials. Largely superseded by recombinant GH (and later by tesamorelin for visceral-fat-specific outcomes).
• Athletic detection studies (Thomas, Pozo, Cabrales et al.) — Multiple LC-MS detection studies for WADA testing. Confirmed reliable identification in serum and urine.

Reconstitution & Storage

GHRP-2 is supplied as a lyophilized powder: sellers list 5 mg and 10 mg vials, and the Japanese product is a single-dose vial of 100 mcg with 25 mg of mannitol, dissolved in 10 mL of saline just before use (GHRP Kaken 100 label, 2025). The first two rows are arithmetic only; the doses are from the dosing table.

• Reconstitution — The Japanese label has the vial dissolved in saline just before injection and used as soon as possible, with stability confirmed for 24 hours at room temperature (GHRP Kaken 100 label, 2025). A seller's guide describes mixing the research-chemical powder with bacteriostatic water.
• Storage — The Japanese label stores the product at 10 °C or below, not frozen, protected from light once out of its box, with a 3-year shelf life (GHRP Kaken 100 label, 2025). A seller's guide describes refrigerating the research-chemical solution after mixing.
• Empty stomach dosing — The label gives the test dose fasting, because food can change GH values (GHRP Kaken 100 label, 2025); a seller's guide describes injecting at least 60 minutes after a meal and eating 30–45 minutes later.

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Side Effects & Risks

GHRP-2's best-documented safety data come from the single test dose behind its Japanese approval (GHRP Kaken 100 label, 2025). Data on repeated use come from small studies lasting days to months; a 2026 review calls it generally well tolerated in short-term studies and notes that no long-term safety data exist (Dominikowski et al., 2026).

• Single-dose diagnostic — The Japanese label lists a feeling of warmth in 16.0% of people given the test dose, and stomach rumbling and a raised white-cell count in 5% or more; low blood pressure, nausea, bloating, drowsiness, runny nose, sweating, thirst, hunger, tiredness and light-headedness in under 5%; and headache, facial flushing, abdominal pain, dizziness and raised ALT at unknown frequency. It also notes reports of pituitary apoplexy, with visual disturbance, headache and vomiting, when a similar drug was given to people with pituitary adenomas (GHRP Kaken 100 label, 2025).
• Appetite stimulation — GHRP-2 raised food intake in healthy men and in people with obesity, comparable in size to ghrelin's, a 2026 review notes (Dominikowski et al., 2026); hunger is on the label's list of reactions to the test dose (GHRP Kaken 100 label, 2025). A seller's guide calls the hunger milder than with GHRP-6; no study cited here compared the two.
• Cortisol and prolactin elevation — In healthy young adults, single IV doses raised prolactin, ACTH and cortisol as much as hexarelin did (Arvat et al., 1997). A 2026 review rates the cortisol rise as documented and the prolactin rise as variable across GHRP-2, GHRP-6 and hexarelin (Dominikowski et al., 2026).
• Water retention (chronic use) — A 2026 review rates fluid retention with GHRPs as theoretical, by way of the rise in GH (Dominikowski et al., 2026); in six GH-deficient children treated for 8 months, no side effects were seen (Mericq et al., 1998). A seller's guide lists water retention in the first few weeks, often easing with continued use.
• Tingling / numbness / mild carpal-tunnel-like symptoms — A seller's guide says some users report mild tingling in the hands and feet, like that seen with GH, and links numbness to high doses; the 2026 review rates such fluid-related symptoms as theoretical for GHRPs (Dominikowski et al., 2026).
• Insulin sensitivity reduction (chronic) — A 2026 review rates insulin resistance with GHRPs as theoretical (Dominikowski et al., 2026), while FDA cites reports of a rising insulin requirement to keep blood glucose controlled in patients given GHRP-2, though causality has not been established (FDA Category 2 safety-risk list, April 2026).
• Tachyphylaxis (chronic) — In nine healthy young men given 100 mcg under the skin daily, the GH response shrank from day 1 to day 5, peak GH falling from 83 to 51 µg/L (Nijland et al., 1998); during a 30-day infusion in 17 older adults, GH secretion stayed above saline, but its rise fell from more than 3-fold on day 1 to more than 1.8-fold on days 14 and 30 (Bowers et al., 2004). In 15 children treated by nasal spray for 6–24 months, the acute GH response did not change (Pihoker et al., 1997). Online protocols describe 8–12-week cycles (Dominikowski et al., 2026).
• Drug interactions — With GHRH, the GH response is larger than with either alone; studies disagree on whether it exceeds their sum (Bowers et al., 2004; Tiulpakov et al., 1995). The label says the test has not been given together with other test drugs such as CRH, gonadorelin or TRH, so the safety of combining them is not established, and that food can change GH values (GHRP Kaken 100 label, 2025).
• Theoretical GH / IGF-1 cancer concern — A 2026 review calls the cancer concern of raised GH and IGF-1 signalling theoretical, with no established clinical signal for GHRP-2 (Dominikowski et al., 2026).
• WADA banned (S2) — Banned at all times for tested athletes. Detection methods well-established; routinely tested by WADA-accredited labs. Any tested athlete using GHRP-2 faces sanction.
• Sourcing risk — Outside the Japan-approved Kaken product, GHRP-2 is sold as a research chemical. FDA says compounded GHRP-2 for injection or nasal use may pose a risk of immune reactions from aggregation and peptide-related impurities, that its unnatural amino acid complicates characterizing it, and that it knows of reports of serious adverse events in patients given GHRP-2, including a rising insulin requirement, deaths of critically ill study subjects, infection and pancreatitis, though causality has not been established (FDA Category 2 safety-risk list, April 2026).

Bloodwork & Monitoring

No trial, label or guideline sets monitoring for repeated use of GHRP-2. The trials measured GH and IGF-1, with IGFBP-3 and osteocalcin, in nine healthy young men (Nijland et al., 1998); GH secretion, IGF-I, IGFBP-3 and IGFBP-5 with routine safety tests in older adults (Bowers et al., 2004); and growth, IGF-1, IGFBP-3 and toxicity measures in children (Pihoker et al., 1997; Mericq et al., 1998). A US men's-health practice tracked IGF-1 and sex hormones in men taking it with testosterone (Sigalos et al., 2017), and a 2026 review for clinicians calls fasting glucose or HbA1c worth checking in people using GH-axis peptides, whatever the compound (Dominikowski et al., 2026).

Commonly Stacked With

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Practical User Notes

• Empty stomach — A seller's guide describes injecting fasted or at least 60 minutes after a meal, and waiting 30–45 minutes before eating, saying carbohydrate-heavy meals blunt the GH response; the Japanese label gives the test dose fasting because food can change GH values (GHRP Kaken 100 label, 2025).
• Pre-bed dose — A seller's guide times one of the day's doses before bed, with the others on waking and after training.
• Stacked with GHRH — Sellers list GHRP-2 pre-blended with CJC-1295 or sermorelin, and a US men's-health practice prescribed it with sermorelin (Sigalos et al., 2017). With GHRH, studies disagree on whether the GH response exceeds the sum of the two (Bowers et al., 2004; Tiulpakov et al., 1995).
• Dose — Online protocols describe 100–150 mcg per dose (Dominikowski et al., 2026), and user forums up to 200 mcg. No trial has set a dose for repeated use; in healthy young adults, 2 mcg/kg IV released more GH than 1 mcg/kg (Arvat et al., 1997).
• Cycles — Online protocols describe 8–12-week cycles (Dominikowski et al., 2026), a seller's guide up to 16 weeks with breaks, and user forums 4 weeks off between cycles. No study has tested cycling; in young men, the GH response to a daily injection shrank within 5 days (Nijland et al., 1998).
• Lab tests — A US men's-health practice tracked IGF-1 and sex hormones in men taking GHRP-2 with testosterone (Sigalos et al., 2017). IGF-1 rose there and during a 30-day infusion in older adults (Bowers et al., 2004), but not after 5 days of daily injections in young men (Nijland et al., 1998) or in the trials in children (Mericq et al., 1998; Tanaka et al., 2014).
• Storage — A seller's guide describes refrigerating it after mixing; the Japanese product is stored at 10 °C or below, not frozen (GHRP Kaken 100 label, 2025).
• Athletes — banned — All GHRPs are banned by WADA at all times. Detection methods established. Not compatible with any anti-doping testing.
• Pregnancy and breastfeeding — The Japanese label rules out the test dose in pregnancy or possible pregnancy, asks doctors to weigh breastfeeding (GHRP-2 passes into milk in rats), and notes no trials in children under 4 (GHRP Kaken 100 label, 2025). No study cited here enrolled people with cancer or diabetes.

Quick Compare — GHRP-2 vs GHRP-6 vs Ipamorelin vs Hexarelin

→ See GHRP-6 profile  •  → See Ipamorelin profile  •  → See Hexarelin profile

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Related Compounds

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References

1. Doi N, Furukawa M, Sato C, Sasaki M, et al. Pharmacological characteristics of KP-102 (GHRP-2), a potent growth hormone-releasing peptide. Arzneimittelforschung. 2004;54(12):857-867. PMID: 15646370. (Foundational pharmacology characterization by Kaken.)
2. Furuta S, Shimada O, Doi N, Ukai K, Nakagawa T, Watanabe J, Imaizumi M. General pharmacology of KP-102 (GHRP-2), a potent growth hormone-releasing peptide. Arzneimittelforschung. 2004;54(12):868-880. PMID: 15646371. (Safety pharmacology evaluation.)
3. Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP 102, WAY GPA 748. Drugs R D. 2004;5(4):236-239. PMID: 15230633. (Drug development profile.)
4. Bowers CY, Reynolds GA, Durham D, Barrera CM, Pezzoli SS, Thorner MO. Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. J Clin Endocrinol Metab. 1990;70(4):975-982. PMID: 2108187. (Bowers' early work on GHRP-GHRH synergy.)
5. Howard AD, Feighner SD, Cully DF, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974-977. PMID: 8688086. (GHS-R1a cloning.)
6. Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999;402(6762):656-660. PMID: 10604470. (Ghrelin discovery — endogenous ligand.)
7. Bowers CY. Unnatural growth hormone-releasing peptide begets natural ghrelin. J Clin Endocrinol Metab. 2001;86(4):1464-1469. PMID: 11297568.
8. Granado M, Priego T, Martín AI, Villanúa MA, López-Calderón A. Anti-inflammatory effect of the ghrelin agonist growth hormone-releasing peptide-2 (GHRP-2) in arthritic rats. Am J Physiol Endocrinol Metab. 2005;288(3):E486-E492. PMID: 15507538.
9. Pihoker C, Badger TM, Reynolds GA, Bowers CY. Treatment effects of intranasal growth hormone-releasing peptide-2 in children with short stature. J Endocrinol. 1997;155(1):79-86. PMID: 9390009. (Pediatric short-stature trial — discontinued therapeutic indication.)
10. 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):2355-2360. PMID: 9661608.
11. Arvat E, Maccario M, Di Vito L, et al. Endocrine activities of ghrelin, a natural growth hormone secretagogue (GHS), in humans: comparison and interactions with hexarelin, a nonnatural peptidyl GHS, and GH-releasing hormone. J Clin Endocrinol Metab. 2001;86(3):1169-1174. PMID: 11238504. (Comparison study.)
12. Pandya N, DeMott-Friberg R, Bowers CY, Barkan AL, Jaffe CA. GH-releasing peptide-6 requires endogenous hypothalamic GH-releasing hormone for maximal GH stimulation. J Clin Endocrinol Metab. 1998;83(4):1186-1189. PMID: 9543138. (GHRH-GHRP synergy.)
13. Kaken Pharmaceutical Co., Ltd. GHRP Kaken 100 (Pralmorelin Hydrochloride) Package Insert and Approved Indication, Japan PMDA, October 2004. (Japan approval reference.)
14. Thomas A, Höppner S, Geyer H, et al. Determination of growth hormone-releasing peptides in serum by LC-MS/MS for sports drug testing. (WADA detection methodology applicable to GHRP-2.)
15. Bowers CY. Growth hormone-releasing peptide (GHRP). Cell Mol Life Sci. 1998;54(12):1316-1329. PMID: 9893708. (Class review.)
16. Berlanga-Acosta J, et al. Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects. Medicc Rev. 2017. PMC5392015. (Class review of cytoprotective evidence.)
17. FDA. Bulk Drug Substances That Raise Significant Safety Risks (Category 2) Under Section 503A / 503B. FDA.gov. Updated 2025-2026.
18. WADA Prohibited List 2026. World Anti-Doping Agency. wada-ama.org. (GHRP family banned under S2.)
19. FDA. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act (503A categories list), versions updated April 15, April 22 and May 14, 2026. fda.gov/media/94155/download. Read October 3, 2026. (Notice that 12 peptides would leave Category 2 because their nominations were withdrawn; their removal; GHK-Cu, except injectable, back in Category 1.)
20. Stone W. The wellness world is eager for RFK Jr.’s promised move on peptides. NPR, March 31, 2026. npr.org/2026/03/31/nx-s1-5768206/peptides-rfk-fda-compounding-pharmacies. Read October 3, 2026. (The HHS secretary’s late-February podcast remarks, “about 14” peptides; reported, not a rule.)
21. Kaken Pharmaceutical Co., Ltd. GHRP Kaken 100 Injection (pralmorelin hydrochloride), Japanese package insert, revised July 2025 (3rd edition); approval no. 21600AMZ00573, launched February 2005. JAPIC package insert via KEGG MEDICUS: kegg.jp/medicus-bin/japic_med?japic_code=00071737. Read October 4, 2026. (Indication, doses by age, timing of the GH peak, adverse reactions, storage. Approved in Japan on October 22, 2004, per KEGG's list of new drug approvals in Japan.)
22. Arvat E, di Vito L, Maccagno B, Broglio F, Boghen MF, Deghenghi R, Camanni F, Ghigo E. 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):885-891. PMID: 9285939. (1 and 2 µg/kg IV in six healthy young adults; 2 µg/kg in six older adults.)
23. Tiulpakov AN, Brook CG, Pringle PJ, Peterkova VA, Volevodz NN, Bowers CY. GH responses to intravenous bolus infusions of GH releasing hormone and GH releasing peptide 2 separately and in combination in adult volunteers. Clin Endocrinol (Oxf). 1995;43(3):347-350. PMID: 7586605. (Eight healthy men: the combined response did not differ from the sum of the separate ones.)
24. Nijland EA, Strasburger CJ, Popp-Snijders C, van der Wal PS, van der Veen EA. A five day treatment with daily subcutaneous injections of growth hormone-releasing peptide-2 causes response attenuation and does not stimulate insulin-like growth factor-I secretion in healthy young men. Eur J Endocrinol. 1998;139(4):395-401. PMID: 9820615.
25. Bowers CY, Granda R, Mohan S, Kuipers J, Baylink D, Veldhuis JD. Sustained elevation of pulsatile growth hormone (GH) secretion and insulin-like growth factor I (IGF-I), IGF-binding protein-3 (IGFBP-3), and IGFBP-5 concentrations during 30-day continuous subcutaneous infusion of GH-releasing peptide-2 in older men and women. J Clin Endocrinol Metab. 2004;89(5):2290-2300. PMID: 15126555.
26. Tanaka T, Hasegawa Y, Yokoya S, Nishi Y. Increased secretion of endogenous GH after treatment with an intranasal GH-releasing peptide-2 spray does not promote growth in short children with GH deficiency. Clin Pediatr Endocrinol. 2014;23(4):107-114. PMID: 25374440. (126 children with GH deficiency at 84 Japanese facilities; double-blind, placebo-controlled, 48 weeks.)
27. Sigalos JT, Pastuszak AW, Allison A, Ohlander SJ, Herati A, Lindgren MC, et al. Growth Hormone Secretagogue Treatment in Hypogonadal Men Raises Serum Insulin-Like Growth Factor-1 Levels. Am J Mens Health. 2017;11(6):1752-1757. PMID: 28830317. (Clinic records: GHRP-2, GHRP-6 and sermorelin, 100 mcg each, three times daily.)
28. Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026;17:1822475. doi:10.3389/fendo.2026.1822475. PMID: 42395176. (Online GHRP-2 dosing protocols; evidence tiers and endocrine signals of GH-axis peptides.)

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• FDA TrackerPCAC voted on 7 of the 12 peptides on July 23–24, 2026; FDA plans a PCAC review of the other 5 before the end of February 2027.