Sports scientists think that the boost in growth hormone levels that occurs after a workout with weights is responsible for muscle growth and rejuvenating effects. If they are right, then taking a low dose of melatonin before training may have interesting effects. According to researchers at Baylor University the supplement raises growth hormone secretion after your workout.
The researchers' discovery is not entirely new and, for the record, they were funded by Iovate Health Sciences. [iovate.com] British endocrinologists discovered in 1999 that after a cardio training session more growth hormone circulates round your body if you take 5 mg melatonin before starting the training.
But does the same work with strength training? That's what the researchers at Baylor set out to find out, and so did an experiment with 30 well-trained men and 30 well-trained women. The subjects all did the same short strength training session early in the afternoon. On one occasion an hour before starting the workout they took a placebo; on the other occasions they took a pill containing 0.5 mg melatonin or a pill containing 5 mg melatonin.
The figures below show what happened to the men. The low dose of melatonin certainly caused an extra high GH peak after the training. There was no effect on the IGF-1 level, which usually rises if the GH level goes up. The melatonin also caused a rise in production of the protein IGFBP-3. This protein makes IGF-1 more effective. There was no effect on IGFBP-1, a protein that neutralises IGF-1.
The researcher's study has made some of the mechanism clearer. Melatonin reduced the secretion of somatostatin, the hormone that inhibits the production of growth hormone.
In the women none of these effects were observed. The researchers don't know why, but it seems that the melatonin trick only works with men.
In 2006 Swedish researchers published the results of a trial in which they got test subjects to do strength training after taking 6 mg melatonin. [Eur J Appl Physiol. 2006 Apr;96(6):729-39.] This dose was too high, and lowered the GH peak.
Strength athletes who believe in the positive effect of the GH peak, could experiment with melatonin supplementation before working out. Low-dose melatonin supplements containing 0.1 mg melatonin per tablet are available in every drug store. Five of these should make up an effective dose. If you take them during the day you shouldn’t have problems with sleepiness: the dose is too light for that.
You could combine melatonin with a mild stimulant, such as caffeine. This not only helps combat sleepiness, but may also boost the effect of the melatonin supplement on the growth hormone peak. One theory is that melatonin stimulates growth hormone secretion by stimulating the secretion of the hormone GHRH. You can increase the manufacture of GHRH during exercise through central alpha-1 and alpha-2 adrenergic stimulation. Read: by using mild stimulants such as caffeine.
J Int Soc Sports Nutr. 2007 Oct 23;4:14.