GHRP-1
The heptapeptide in the original growth hormone-releasing peptide family
GHRP-1 is a synthetic seven-amino-acid peptide, Ala-His-D-beta-Nal-Ala-Trp-D-Phe-Lys amide, from the same series of growth hormone-releasing peptides as GHRP-2 and GHRP-6. It released growth hormone in healthy children and in pituitary cells, but it was never developed into a medicine. WADA names it as a prohibited growth hormone releasing factor.
What is it?
The growth hormone-releasing peptides, or GHRPs, are small synthetic peptides that release growth hormone from the pituitary. GHRP-6 is a hexapeptide; GHRP-1 is a heptapeptide that carries two D-amino acids, D-beta-naphthylalanine and D-phenylalanine. In rat pituitary cells it tripled growth hormone release without raising cAMP, and in sheep pituitary cells its effect was abolished by calcium-channel blockade but untouched by a GHRH antagonist, evidence that it works through a different receptor from GHRH.
The main human study is from 1993. A single intravenous bolus of 1 microgram per kg was given to 15 short but healthy children and adolescents and 8 young patients with pituitary insufficiency. Every healthy child showed a rise in growth hormone peaking at 15 to 30 minutes, larger in pubertal than prepubertal children and similar to the response to GHRH. Six of the hypopituitary patients responded to neither. Free thyroxine rose and TSH fell, both within normal limits, and cortisol rose briefly.
Other species were less impressed. In lambs, only the highest dose released significant growth hormone, and even that was surpassed by a much smaller dose of GHRH, matching cell-culture data showing GHRP-1 ten times less active than GHRH in sheep. In cultured human thyroid follicles it inhibited TSH-stimulated hormone secretion, which GHRH did not, another sign that the two act differently.
GHRP-1 was never developed into a medicine. Today it appears mainly in anti-doping science: WADA names it under S2.2.4, and a 2015 study gave it nasally to a volunteer and found it is excreted as metabolites, not intact, with one fragment detectable in urine for 27 hours.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Published Research
Studies of GHRP-1, from their PubMed abstracts.
Children and adolescents
An IV bolus of 1 microgram/kg raised growth hormone in all 15 healthy short children, peaking at 15-30 minutes and higher in pubertal children; 6 hypopituitary patients did not respond. Free T4 rose, TSH fell and cortisol rose briefly; prolactin, LH and FSH did not change.
Urinary metabolites after nasal dosing
After nasal GHRP-1 in one volunteer, six metabolites were identified and the parent peptide was not detected; GHRP-1 (2-4) free acid was detectable in urine for up to 27 hours.
Rat pituitary cells
GHRP-1 increased growth hormone release up to 3-fold in rat pituitary cells without affecting cAMP.
Sheep pituitary cells
KP 101 released growth hormone dose-dependently with half-maximal effect at 10^-7 M, ten times higher than GRF; calcium-channel blockade abolished the effect and a GRF antagonist did not.
Lambs
In 8 lambs, only 6 nmol/kg GHRP-1 released significant growth hormone (peak 35.1 ng/mL), surpassed by 0.3 nmol/kg GHRH (51.6 ng/mL).
Human thyroid follicles
GHRP-1, but not GHRH, dose-dependently inhibited TSH-stimulated T3 secretion and cAMP formation in cultured human thyroid follicles.
Side Effects & Contraindications
Reported Side Effects
From the 1993 study in children.
Contraindications & Cautions
There is no label.
Legal Status
GHRP-1 was never approved and is prohibited in sport.
Frequently Asked Questions
?What is GHRP-1?
A synthetic seven-amino-acid growth hormone-releasing peptide from the same research series as GHRP-2 and GHRP-6. It releases growth hormone from the pituitary through a route separate from GHRH.
?How does GHRP-1 compare with GHRP-6 and GHRP-2?
In sheep pituitary cells GHRP-1 and GHRP-6 had the same potency and similar maximal effects. GHRP-2, also known as pralmorelin, is the better-studied family member; GHRP-1 was never developed into a medicine.
?Is GHRP-1 banned in sport?
Yes. WADA's 2026 and 2027 lists name GHRP-1 among the GH-releasing peptides under S2.2.4, prohibited at all times.
?Has GHRP-1 been tested in people?
In a 1993 study it was given once intravenously to children and adolescents, raising growth hormone in all the healthy ones. There are no treatment trials.
References
- [other] PubChem CID 10350910, GHRP-1: formula C51H62N12O7, molecular weight 955.1. Read October 3, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/10350910
- [fda] FDA. Drugs@FDA (openFDA): no application on record for GHRP-1. Read October 3, 2026.
- [regulation] World Anti-Doping Agency. Prohibited List 2026 and 2027, S2.2.4 Growth hormone releasing factors: GH-releasing peptides (GHRPs), e.g. alexamorelin, examorelin (hexarelin), GHRP-1, GHRP-2 (pralmorelin), GHRP-3, GHRP-4, GHRP-5 and GHRP-6. Read October 3, 2026.
- [pubmed] Laron Z, et al. "Growth hormone-releasing activity of growth hormone-releasing peptide-1 (a synthetic heptapeptide) in children and adolescents." Acta Endocrinol (Copenh), 1993;129(5):424-6. PMID: 8279223.
- [pubmed] Semenistaya E, et al. "Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin." Drug Test Anal, 2015;7(10):919-25. PMID: 25869809.
- [pubmed] Akman MS, et al. "Mechanisms of action of a second generation growth hormone-releasing peptide (Ala-His-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2) in rat anterior pituitary cells." Endocrinology, 1993;132(3):1286-91. PMID: 8095015.
- [pubmed] Wu D, et al. "Effects in vitro of new growth hormone releasing peptide (GHRP-1) on growth hormone secretion from ovine pituitary cells in primary culture." J Neuroendocrinol, 1994;6(2):185-90. PMID: 8049717.
- [pubmed] Charrier J, et al. "In vivo effects of the GH-releasing heptapeptide GHRP-1 in lambs." Reprod Nutr Dev, 1998;38(3):245-54. PMID: 9698275.
- [pubmed] Kraiem Z, et al. "Growth hormone (GH)-releasing heptapeptide, but not GH-releasing hormone, inhibits thyrotropin-stimulated thyroid hormone secretion and cAMP formation in cultured human thyroid follicles." Eur J Endocrinol, 1995;133(1):117-20. PMID: 7627332.
Sources & Citations
Studies were read from their PubMed records, October 3, 2026.
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