What it is
GHRP-2, also called pralmorelin, is a synthetic hexapeptide growth hormone secretagogue from a series developed at Tulane University and Polygen. It is studied in endocrinology as a potent stimulus of growth hormone release and as a tool for ghrelin receptor research. In Japan it is approved only as a diagnostic agent for growth hormone deficiency, and it is not approved as a therapy in any major market.
How it works
GHRP-2 is an agonist at the growth hormone secretagogue receptor GHS-R1a, the ghrelin receptor, at pituitary and hypothalamic level. In human studies it released more growth hormone than GHRH and also raised prolactin, ACTH and cortisol to a lesser degree.
Regulatory status
- Cosmetic ingredient
- Research compound
- In clinical trials
- Approved medicine
Not approved as a medicine by the FDA or the EMA. Some are registered in individual countries. Supplied for laboratory research only.
What published research is studying
- Diagnosis of adult growth hormone deficiency as an alternative to the insulin tolerance test
- Appetite and food intake through ghrelin receptor activation in healthy men
- Reactivation of the growth hormone, thyroid and gonadal axes in prolonged critical illness
- Long-term oral use and appetite in children with growth hormone deficiency
Key findings
In a validation study of 77 healthy subjects and 58 patients with growth hormone deficiency confirmed by insulin tolerance test, peak growth hormone after a single intravenous GHRP-2 dose was 1.36 micrograms per litre in patients versus 84.6 in healthy subjects, supporting a diagnostic cut-off of 15 micrograms per litre.
Chihara K et al., Eur J Endocrinol 2007In 7 lean healthy men given a 270-minute subcutaneous GHRP-2 or saline infusion before a buffet meal, energy intake was 35.9% higher with GHRP-2, and every subject ate more.
Laferrère B et al., J Clin Endocrinol Metab 2005In a randomised 5-day trial in 33 men with prolonged critical illness, GHRP-2 infusion alone reactivated growth hormone secretion and normalised IGF-I, IGFBP-3 and acid-labile subunit, but reduced ureagenesis only when combined with TRH, with or without GnRH.
Van den Berghe G et al., Clin Endocrinol (Oxf) 2002In 10 prepubertal children with growth hormone deficiency given oral GHRP-2 for 12 months, 7 reported an increase in appetite during the first 6 months, while the change in BMI SDS (0.21 to 0.25) was not statistically significant.
Mericq V et al., J Pediatr Endocrinol Metab 2003
What the studies measured
Study durations
- Diagnostic test: blood sampled for 2 hours after a single intravenous dose (Chihara et al. 2007).
- Critical illness trial: 5 days of continuous infusion, with nocturnal hormone sampling at baseline and on nights 1 and 5 (Van den Berghe et al. 2002).
- Oral paediatric study: 12 months of twice-daily dosing in children with growth hormone deficiency (Mericq et al. 2003).
- Food intake study: a single 270-minute subcutaneous infusion before an ad libitum meal (Laferrère et al. 2005).
Endpoints
- Peak serum growth hormone after a single intravenous dose
- Diagnostic cut-off against the insulin tolerance test
- Ad libitum energy intake at a buffet meal
- Pulsatile GH, TSH and LH secretion by deconvolution analysis
- Serum IGF-I, IGFBP-3 and acid-labile subunit
How strong is the evidence?
Human data are solid for single-dose diagnostic use, which is approved in Japan, but studies of repeated dosing are small and short, and none has shown a lasting therapeutic benefit.
Common questions
Is GHRP-2 an approved medicine?
Research compound. Not approved as a medicine by the FDA or the EMA. Some are registered in individual countries. Supplied for laboratory research only.
How much human research is there on GHRP-2?
Human data are solid for single-dose diagnostic use, which is approved in Japan, but studies of repeated dosing are small and short, and none has shown a lasting therapeutic benefit.
Does UU supply GHRP-2?
Yes, as premium-grade research material for laboratory use. Every batch is tested by an independent lab and the certificate of analysis is published.