GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Blocked growth hormone-releasing peptide (GHRP-6)-induced GH secretion and absence of the synergic action of GHRP-6 plus GH-releasing hormone in patients with hypothalamopituitary disconnection: evidence that GHRP-6 main action is exerted at the hypothalamic level.
Popovic. V V; Damjanovic. S S; Micic. D D; Djurovic. M M; Dieguez. C C; Casanueva. F F FF
Key Findings
- GHRP-6 alone raises GH levels about three times higher than GHRH alone in healthy subjects.
- Combining GHRP-6 with GHRH produces a synergistic GH surge that is far greater than the sum of each alone.
- In individuals with hypothalamic‑pituitary disconnection, GHRP-6 fails to stimulate GH, indicating its primary action is at the hypothalamic level.
Practical Outcomes
- For most biohackers, using GHRP-6 can effectively boost GH, especially when paired with a GHRH analog for a synergistic effect. Ensure your hypothalamic function is intact; if you have conditions affecting the brain‑pituitary axis, GHRP-6 may not work. Typical dosing in studies is around 90‑100 µg per injection, often given 2‑3 times daily, but start low and monitor responses.
Summary
The study shows that GHRP-6 triggers a strong release of growth hormone (GH) by acting mainly on the brain (hypothalamus). In healthy people it works even better when paired with a GH‑releasing hormone (GHRH) drug, creating a big boost in GH. However, in patients whose hypothalamus‑pituitary connection is broken, GHRP-6 barely works, confirming its hypothalamic site of action.
Abstract
GH-releasing peptide (GHRP-6; His-D Trp-Ala-Trp-D Phe-Lys-NH2) is a synthetic compound that releases GH in a specific and dose-related manner through mechanisms and a point of action that are mostly unknown but different from those of GHRH. In man, GHRP-6 is more efficacious than GHRH, and a striking synergistic action on GH release is observed when GHRP-6 and GHRH are administered simultaneously. Based on such a synergistic action, it has been hypothesized that GHRP-6 acts through a double mechanism by actions exerted both at the pituitary and hypothalamic levels. The aim of the present study was 2-fold: 1) to further characterize the mechanism of action and synergistic effects of GHRP-6; and 2) to study its action in patients with hypothalamopituitary disconnection. Twelve patients with different neuroendocrine pathologies leading to a state of hypothalamopituitary disconnection (functional stalk section) and 11 age- and sex-matched normal controls were studied. Each subject underwent 3 tests on separate occasions, being challenged with GHRH (100 micrograms, i.v.), GHRP-6 (90 micrograms, i.v.), or GHRH plus GHRP-6. GH was analyzed as the area under the curve (mean +/- SE, micrograms per L/120 min). In normal subjects GH secretion was 483.7 +/- 99.2 after GHRH, 1434.8 +/- 393.0 after GHRP-6, and 3771.5 +/- 399.6 after GHRH plus GHRP-6; the level of GH secreted after GHRH plus GHRP-6 treatment was significantly (P < 0.05) higher than after the arithmetic sum of GH levels after both compounds administered separately. In the group of patients with hypothalamopituitary disconnection, the level of GH secreted after GHRH was similar to that in controls (423.4 +/- 62.8); however, a complete blockade was observed after GHRP-6 (97.3 +/- 7.9), significantly (P < 0.05) lower than after GHRH as well as lower than the GHRP-6-induced GH release in control subjects (P < 0.01). After GHRH plus GHRP-6, the patients with hypothalamopituitary disconnection showed severely reduced secretion (745.3 +/- 67.6; P < 0.01 vs. controls), a value that was not significantly different from the arithmetic addition of levels produced by both compounds administered separately.(ABSTRACT TRUNCATED AT 400 WORDS)
Study Information
pubmed
1995
10.1210/jcem.80.3.7883854