GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Intranasal activity of the growth hormone releasing peptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 in conscious dogs.
Nelson. A H AH; Walker. R F RF; Codd. E E EE; Barone. F C FC
Key Findings
- Intranasal GHRP‑6 increased plasma GH in dogs in a dose‑related way (0.25 mg/kg → ~11 ng/ml, 0.5 mg/kg → ~29 ng/ml).
- GH peaks occurred ~15 minutes after nasal dosing and stayed elevated for up to 105 minutes.
- Estimated intranasal bioavailability was 34‑45% of the IV route.
- IV administration at the same dose produced a higher GH peak (~61 ng/ml), confirming the peptide is active when given systemically.
Practical Outcomes
- For biohackers, this study suggests that a nasal spray of GHRP‑6 could be a viable, needle‑free way to stimulate GH, potentially improving compliance and comfort. While the data are from dogs, the reported bioavailability (~35‑45%) provides a starting point for estimating human nasal doses. Human trials are needed, but the findings support experimenting with intranasal delivery as an alternative to subcutaneous injections.
Summary
Giving GHRP‑6 as a nasal spray in dogs caused a clear, dose‑dependent rise in growth hormone, with the biggest spike about 15 minutes after dosing and the effect lasting up to 1½ hours. The peptide was about one‑third to one‑half as effective as an IV injection, suggesting that a nasal route could work in people and be more comfortable than shots.
Abstract
This series of experiments was conducted to evaluate the growth hormone (GH) releasing activity of intranasally administered His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6, SK&F 110679) in conscious dogs. Intranasal administration of GHRP-6 increased plasma growth hormone levels in the conscious dog in a dose-related manner. Doses of 0.25 and 0.5 mg/kg produced GH levels of 11.3 +/- 4.8 ng/ml and 28.6 +/- 8.0 ng/ml, respectively. Peak levels were observed 15 minutes after dosing and GH levels were elevated for up to 105 minutes after intranasal dosing. Intranasal administration of isotonic saline did not produce any change in basal (negligable) GH levels. When GHRP-6 was given by the intravenous route, a maximal dose of 0.5 mg/kg, produced a peak plasma GH concentration of 60.8 +/- 10.5 ng/ml. Saline had no effect on GH levels when given intravenously. Using the intravenous and intranasal GH response data (i.e., area under the time-response curves), the intranasal bioavailability of GHRP-6 was estimated to be 34.4 to 44.9%. The results of these studies suggest that significant activity and excellent bioavailability can be achieved when GHRP-6 is administered by the intranasal route to conscious dogs. Based on these results, the intranasal activity of GHRP-6 should be evaluated in man. The successful intranasal administration of this peptide in man should provide GH therapy with reduced patient discomfort and better patient compliance when compared to presently available parenterally administered remedies.
Study Information
pubmed
1991
10.1016/0024-3205(91)90344-b