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14.11.2009


Zinc megadose gives 40 percent more free testosterone

Zinc supplements enhance testosterone levels. If you give athletes a daily dose of 3 mg zinc sulfate [appr. 1 mg elemental zinc] per kg bodyweight, after four weeks they’ll have 40 percent more free testosterone in their blood. Researchers at the Selcuk University in Turkey discovered this when they did an experiment with 10 male wrestlers.


In the previous posting we wrote about this Turkish zinc research. In those studies, mice and physically inactive students made more testosterone when they were given hefty doses of zinc. In this study, the researchers looked at the effect of zinc on highly-trained wrestlers. The subjects had an average age of 19 and had been training five days a week for at least six years.

The wrestlers did weight training once a week, cross training once a week and wrestling-specific training on the other three days.

Before and after the four-week period of zinc supplementation, the researchers got their test subjects to cycle until they reached the point of exhaustion. Before and after the test, the researchers measured the concentrations of thyroxine and testosterone in the subjects’ blood. Under normal conditions, heavy physical exertion lowers the concentration of these hormones. The figure below shows how the zinc supplements prevented this from happening. The supplements also resulted in a 40 percent increase in the amount of free testosterone before the exhaustion test.



The same effect was also seen on the concentrations of thyroxine and free T3 and T4 in the blood.



Many enzymes use zinc in the processes of hormone production and of generating energy from fats or carbohydrates. Physical exertion requires large amounts of zinc, the researchers believe. Such large amounts that zinc supplements can help athletes to improve their performance. "Physiological doses of zinc supplementation can prove beneficial to performance", they write.

If you weigh 80 kg and you want to use zinc in similar doses to those used by the Turkish wrestlers, you’ll need to take 240 mg zinc sulfate a day [appr. 80 mg elemental zinc]. Long-term use of such high doses of zinc is not safe. Researchers have reported side-effects from much lower intake levels. According to Chinese researchers, a daily dose of 50 mg zinc leads to higher cholesterol levels in humans within a couple of weeks. [Wei Sheng Yan Jiu. 2004 Nov;33(6):727-31.] The American epidemiologists Walter Willett and Ed Giovannucci discovered that zinc supplements at doses higher than 100 mg per day increased the risk of prostate cancer by a factor of 2.2. [J Natl Cancer Inst. 2003 Jul 2;95(13):1004-7.]

Source:
Neuro Endocrinol Lett. 2006 Feb-Apr; 27(1-2):247-52.

More:
It really works – zinc is a T-booster 13.11.2009
Animal study: copper chloride is T-booster 23.07.2009
Calcium raises T-levels in athletes 08.04.2009
Study: ZMA does not raise testosterone levels 07.04.2009
Combination of selenium and NAC raises testosterone levels 18.01.2009
More magnesium, more free testosterone 11.11.2008