Synergy of L-arginine and GHRP-2 stimulation of growth hormone in men and women: modulation by exercise.
Wideman. L L; Weltman. J Y JY; Patrie. J T JT; Bowers. C Y CY; Shah. N N; Story. S S; Veldhuis. J D JD; Weltman. A A
Key Findings
- L‑arginine (30 g) and GHRP‑2 (1 µg/kg) together produce a supra‑additive increase in GH at rest (AG > G > A > saline).
- A 30‑minute aerobic exercise session still raises GH but reduces the extra synergistic effect seen with the combination at rest.
- Gender influences the timing and half‑life of the GH response, but not the total amount of GH released.
Practical Outcomes
- For biohackers aiming to maximize GH spikes, the most effective protocol is to take L‑arginine and GHRP‑2 together on rest days or before sleep, rather than during or right after cardio. The suggested doses are 30 g of oral L‑arginine over 30 minutes and a sub‑microgram per kilogram IV or sub‑cutaneous bolus of GHRP‑2. Exercise already elevates GH, so the added benefit of the combo is smaller on workout days, and men may see a slightly quicker GH peak than women.
Summary
In healthy men and women, taking a large dose of L‑arginine (30 g) together with a small dose of GHRP‑2 (about 1 µg per kg body weight) creates a strong, more‑than‑additive boost in growth hormone (GH). This boost is biggest when you’re at rest; doing a 30‑minute aerobic workout still raises GH but cuts down the extra synergy between the two compounds. Men and women show the same overall boost, but they differ in how fast GH peaks and how long it stays in the blood.
Abstract
We investigated the ability of exercise, a multipathway, potent, physiological stimulus for GH release, to alter the synergistic interaction of L-arginine (A) and GH-related peptide (GHRP)-2 (G) observed at rest and the ability of gender to further modulate this putative interaction. Subjects (9 men and 9 early follicular phase women) completed 30 min of constant load aerobic exercise in combination with intravenous infusions of saline (S), A (30 g over 30 min), G (1 microg/kg bolus), or both (AG) in separate study sessions in randomly assigned order. Measures of GH release were logarithmically transformed for statistical analysis. Similar to rest, exercise maintained the rank order (AG > G > A > S) of effective stimulation of GH release for the key response measures in men or women, a gender disparity in the time to reach the maximal serum GH concentration, the calculated endogenous GH half-life, and the observed effect of preinfusion (basal) serum GH concentrations on determining secretagogue responsiveness. Exercise potentiated the individual stimulatory actions of A and G, while blunting the relative magnitude of the synergistic (supra-additive) interaction observed at rest. We infer from the present data that 1) exercise is likely to induce release of both GHRH and somatostatin, 2) L-arginine may facilitate the effect of exercise by limiting somatostatin release, 3) GHRP-2 could further enhance the stimulatory impact of exercise by opposing central actions of somatostatin and/or heightening endogenous GHRH release, and 4) gender strongly controls the relative but not absolute magnitude of A/G synergy both at rest and after exercise.
Study Information
pubmed
2000
10.1152/ajpregu.2000.279.4.r1467