Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring neurotransmitter which plays a pivitol role in the sleep-wake cycle, as well as various other physiological functions.
While Melatonin supplements are commonly taken for sleep-related issues, there has been a relatively substantial amount of research conducted on its role in regulating Growth Hormone release.
The purpose of this article is to bring about a better understanding of the effects Melatonin supplementation on Growth Hormone in humans and determined the implications for athletes and non-athletes.
Though Melatonin has also been thoroughly researched as a sleep-aid, that is beyond the scope of this article, as we will solely be focusing on its potential as a GH booster/optimizer.
What Does The Research Tell Us?
A 1998 study from “Clincal Endocrinology” noted that, while there was a slight increase in GH release in response to Melatonin supplementation, when studied over a 24 hour period, this increase was not statistically significant compared to placebo.
A 1999 study, again published in “Cinical Endrocrinology”, found that healthy volunteers who consumed either .5 or 5mg of Melatonin experienced significant increases in circulating Growth Hormone levels, with levels returning to normal about 150 minutes after ingestion.
A 2007 study, published in the “Journal of the International Society of Sports Nutrition”, found that subjects given .5 or 5mg of Melatonin prior to exercise experienced an increase in exercise-induced GH release, with 5mg being the most effective.
A 1999 study from the “European Journal of Endrocrinology” found that Melatonin (5mg) increased the GH response to exercise roughly 70%. However, in a later (2006) study from the same journal, subjects who received 6mg of Melatonin prior to resistance training actually experienced a decreased GH response. The reason for the discrepancy is unknown.
How Does Melatonin Increase Growth Hormone?
Melatonin’s effect on Growth Hormone release appears to be via increasing the responsiveness of the Pituitary Gland to Growth Hormone Releasing Hormone (GHRH), as evidenced in a 1993 study from “Clinical Endrocrinology” in which Melatonin administration prior to GHRH administration resulted in a significantly greater GH spike.
GHRG, as the name implies, is a hormone which signals the release of Growth Hormone, but the Pituitary Gland can become less sensitive (i.e. release less GH). Melatonin can increase this sensitivity, ultimately resulting in a larger GH spike than would normally occur otherwise.
How To Take Melatonin
While efficacy has been noted with doses ranging from .5 to 5mg, 5mg has been shown to elevate exercise-induced GH release more so than the lower dose of .5mg. However, in a rested state (not during exercise), .5mg is roughly as effective as 5mg, so the dose isn’t so important.
If you are taking Melatonin as a sleep-aid before bed, .5mg is the recommended dose, as higher doses will not meaningfully influence sleep or GH release beyond what can be accomplished with the lower dose.
THE BOTTOM LINE
Melatonin supplementation can increase Growth Hormone release, both in a rested state and before exercise, though the research regarding exercise-induced GH release is mixed.
While there is not much conclusive evidence to suggest Melatonin supplementation could hinder exercise performance, it is most commonly taken at night (before bed) as a sleep-aid, rather than prior to rigorous exercise and the research regarding GH release in a rested state is unanimous.
Given that there are other supplements (like Alpha GPC) that can increase exercise-induced GH response, it may be best to leave the Melatonin for before bed.
Although supplementation may not raise total 24-hour GH levels to a particularly meaningful degree, it is a viable option for optimizing and ensuring adequate levels during rest.
Since GH plays an integral role in growth, exercise recovery, and maintaining a favorable body composition, Melatonin is a logical addition to the supplement regimen of athletes and bodybuilders alike.
- Valcavi, Roberto, et al. “Melatonin stimulates growth hormone secretion through pathways other than the growth hormone‐releasing hormone.” Clinical endocrinology 39.2 (1993): 193-199.
- Forsling, Mary L., M. J. Wheeler, and A. J. Williams. “The effect of melatonin administration on pituitary hormone secretion in man.” Clinical endocrinology51.5 (1999): 637-642.
- Kostoglou‐Athanassiou, Ifigenia, et al. “Melatonin administration and pituitary hormone secretion.” Clinical endocrinology 48.1 (1998): 31-37.
- Nassar, Erika, et al. “Effects of a single dose of N-Acetyl-5-methoxytryptamine (Melatonin) and resistance exercise on the growth hormone/IGF-1 axis in young males and females.” Journal of the International Society of Sports Nutrition 4.1 (2007): 1-13.
- Meeking, D. R., et al. “Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects.” European journal of endocrinology 141.1 (1999): 22-26.
- Mero, Antti A., et al. “Effects of resistance exercise session after oral ingestion of melatonin on physiological and performance responses of adult men.”European journal of applied physiology 96.6 (2006): 729-739.