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07.04.2009

Study: ZMA does not raise testosterone levels

ZMA is ineffective, say German sports scientists in an article published in the European Journal of Clinical Nutrition. The researchers tested a couple of bottles of SNAC System's ZMA from the bodybuilding.com webshop. SNAC is Victor Conte's company, the genius behind the BALCO scheme and the inventor of ZMA.

The team of researchers led by Wilhelm Schaenzer gave seven fitness fanatics the recommended dose of ZMA – three capsules per day, providing a total of 30 milligrams of zinc, 450 milligrams of magnesium and 11 milligrams of vitamin B6. The researchers made sure the athletes followed the advice of the manufacturer. The participants were asked to swallow the capsules with water between dinner and bedtime at minimum 1 h after the last food intake. Seven other athletes were given a placebo.

The Germans then monitored the concentration of androgens in the blood their subjects for 56 days. The results are shown below. The white bars represent the testosterone level of the test subjects in the placebo group. The grey bars represent the testosterone level of the test subjects in the ZMA group.

Effect: nada.

When the researchers measured the concentrations of a series of natural androgens in the test subjects' urine the story was pretty much the same. ZMA does not raise the androgen level.

The researchers measured the zinc intake of the athletes before starting the experiment. Their levels were between 12 and 23 milligrams per day. Their mean intake was more than the daily requirement. Recent trials have shown that athletes make more testosterone if they take zinc supplements. [Neuro Endocrinol Lett. 2006 Feb-Apr;27(1-2):247-52.] But these athletes may have had a zinc deficiency, the Germans reason.

ZMA has been tested a couple of times. In the first case ZMA came out tops, and the abstract of the study was distributed to much acclaim. That research was done by supplements manufacturer himself. The research was published on the JEPonline website. [JEPonline, 3(4): 26-36, 2000.]

A few years later, Richard Kreider studied the effectiveness of ZMASS, a supplement containing ZMA and L-Dopa produced by Cytodyne. ZMASS did almost nothing. [J Int Soc Sports Nutr. 2004 Dec 31;1(2):12-20.]

The Germans also discovered that the supplement scarcely raised zinc levels in the body. The athletes excreted nearly all the extra zinc in their urine. ZMA users also urinated more – which explains why some ZMA users think that the stuff makes them more ripped. They dehydrate.

Source:
Eur J Clin Nutr. 2009 Jan;63(1):65-70.