What Is ZMA?

ZMA is a combination of the minerals zinc monomethionine aspartate, magnesium aspartate and vitamin B-6. This is a scientifically designed, patent-pending formula. Zinc is an essential trace mineral that is required as a cofactor by more than 100 enzymes in the body. Enzymes are important for many biochemical reactions. Zinc is also critical for protein synthesis and tissue repair after injury. Like zinc, magnesium is an essential mineral. It’s also involved in numerous enzymatic reactions in the body. Magnesium is important for cardiovascular, metabolic and bone health. It also helps maintain normal muscle and nerve function. Vitamin B-6 is involved in protein metabolism. In addition, it assists in releasing stored glucose from glycogen.

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Benefits Of ZMA

  • Enhanced testosterone production which may lead to increased muscle mass and strength
  • Improved sleep quality which can improve recovery from exercise
  • Increased libido due to increased testosterone production

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Evidence Behind ZMA

The most well-known research on ZMA’s anabolic benefits was a 2000 study performed at Western Washington University (Bellingham). The researchers had NCAA football players take ZMA or a placebo nightly. They engaged in an eight-week spring-training program. They discovered the following: athletes taking the ZMA supplement experienced a 30% increase in both free and total testosterone levels. Additionally, there was a 4% increase in insulin-like growth factor-I levels. Those taking a placebo had a 10% decrease in both free and total testosterone levels. Also, they had a 22% decrease in IGF-I. Finally, the ZMA athletes made significantly greater gains in strength and power compared to the placebo group. Analysis of the athletes’ diets found that they were consuming well over the recommended intake for zinc. ZMA produced these benefits despite their zinc intake.

More ZMA Research

Besides the Western Washington study, several others also find that zinc and magnesium offer anabolic properties. One of the most recent is a 2007 study from Selcuk University (Konya, Turkey). This study reported that four weeks of zinc supplementation in men increased both free and total testosterone levels at rest. It also increased total test levels after exercise. The researchers found similar results on testosterone levels in an earlier zinc study. This time, the test subjects were competitive wrestlers.

Researchers from the U.S. Department of Agriculture reported that zinc depletion caused the following: Decreased muscle endurance in the lower and upper body in test subjects. This means that maintaining zinc levels helps you complete a number of reps with a given weight. This is especially true during a workout consisting of several sets.

What About Magnesium?

Researchers at the Western Washington University discovered the following. In an earlier study, test subjects took a daily magnesium supplement. They followed a seven-week leg-training program. At the end, they increased their leg strength by 20% over those taking a placebo.

ZMA & Cortisol

Zinc and magnesium supplements have been shown to significantly decrease the levels of the catabolic hormone cortisol. A study conducted by researchers at Justus Liebig University (Giessen, Germany) revealed the following: Triathletes taking a magnesium supplement for four weeks had significantly lower cortisol levels. This was true at rest and after a triathlon. Test subjects taking a placebo did not experience these results.

Brazilian researchers studied the effects of a single dose of zinc. Test subjects given a single dose of zinc experienced a significant drop in blood cortisol levels within two hours. Keeping cortisol lowered can be critical for muscle growth and strength gains. Cortisol competes with testosterone, decreasing anabolism and enhancing muscle breakdown. Maintaining an anabolic state is critical to your muscle building success. This is why the recovery process is so important. Training in and of itself is a catabolic event which many people don’t understand. True, you must stimulate the muscles in the gym. However, the actual process of growth really begins with recovery. This is the beginning of muscle repair and the replenishing of store glycogen. It’s also the beginning of getting the body back to an anabolic state.


In addition to boosting testosterone and IGF-I and blunting cortisol, ZMA may also indirectly enhance growth hormone levels. ZMA aids sleep quality because magnesium can normalize and extend stage 3 and 4 slow-wave sleep. This is critical. Deeper sleep can help to raise GH levels, which peak during the night. Improved sleep quality also aids the recovery process. As talked about above, recovery is critical to your results. So we see that ZMA has an impact on the natural anabolic hormones of the body. Not to mention the recovery ability of the body.

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ZMA Supplements, Timing and Dosage

ZMA supplements come in pill or capsule form, as pure ZMA or as part of a testosterone boosting complex. To a lesser extent ZMA can be part of a natural sleep aid complex. The dosage and proportion is very important: 450 mg of magnesium to 30 mg of zinc to 11 mg of B6. Most ZMA products will have this proportion.

ZMA Dosage

It’s typically taken twice daily. Once prior to training and again on an empty stomach before bed. This is important due to its effects on sleep. On non training days it would be taken twice. First in the early afternoon and then again before bed. ZMA is all natural and has no reported side effects. Dosages may vary between products, always follow the instructions on the label.

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