GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Diagnosis of growth hormone deficiency in adults: provocative testing with GHRP6 in comparison to the insulin tolerance test.
Alaioubi. B B; Mann. K K; Petersenn. S S
Key Findings
- GHRP‑6 (1 µg/kg) produced a clear GH response that could differentiate deficient (peak ~3 µg/L) from sufficient (peak ~15 µg/L) patients.
- A GH peak cut‑point of 3.5 µg/L gave 80% sensitivity and 95% specificity for diagnosing GH deficiency.
- Using lower (3.5 µg/L) and upper (11.3 µg/L) cut‑offs allowed a definitive diagnosis in ~66% of patients, reducing the need for the insulin tolerance test.
- No adverse effects were reported during GHRP‑6 administration.
Practical Outcomes
- For biohackers interested in assessing their own GH status, a GHRP‑6 challenge could serve as a safer, outpatient screening tool, but ambiguous results will still require the traditional insulin tolerance test. The identified cut‑offs help interpret the GH spike, and the lack of side effects supports its short‑term use in a clinical or supervised setting.
Summary
The study shows that giving a single dose of GHRP‑6 can trigger a growth‑hormone spike that helps doctors tell if an adult has GH deficiency. A GH level above 11.3 µg/L basically rules out deficiency, while a level below 3.5 µg/L confirms it, covering about two‑thirds of cases without needing the risky insulin tolerance test. No side effects were seen.
Abstract
The aim of the study was to evaluate the clinical applicability of growth hormone releasing peptide 6 (GHRP6) for the diagnosis of GH deficiency in adults. Forty-nine patients with suspected hypothalamic or pituitary disease underwent both ITT and GHRP6 (1 microg/kg) testing. In addition, 20 healthy controls were tested by GHRP6 only. Blood samples were analyzed for GH levels. Thirty patients had a GH peak response of less than 3 microg/l during ITT and were considered growth hormone deficient (GHD). For the GHRP6 test, the GH mean peak was 3.0 microg/l (+/-0.8, 0.5-20.9) in the GHD group vs. 14.8 microg/l (+/-4.7, 1.8-95.3) in the growth hormone sufficient (GHS) group. Receiver operating characteristics (ROC) analysis suggested an optimal peak GH cut-point of 3.5 microg/l with 80% sensitivity and 95% specificity. Applying upper (11.3 microg/l) and lower (3.5 microg/l) cutoffs with high specificities established the diagnosis in nearly two third of the patients. During administration of GHRP6 no side effects were observed. GHRP6 alone as a provocative test is highly specific, but with limited sensitivity for the diagnosis of GH deficiency in adults. Using upper and lower cutoffs, further testing by ITT may be necessary in only one-third of patients.
Study Information
pubmed
2008
2008-11-12T00:00:00.000Z
10.1055/s-0028-1093350
1
20