ZMA is a combination of zinc, magnesium, and vitamin B6. Consequently, ZMA’s benefits are similar to those of its individual components.
The official ZMA formula was created by sports supplement developer Victor Conte for SNAC System, Inc., a sports nutrition company. SNAC System’s ZMA formula is still patent-pending. Many other sports supplement companies have created their own ZMA products.
ZMA is used by both men and women.
ZMA is most commonly used as a natural athletic performance enhancer. It is meant to increase muscular strength and improve muscle recovery.
A trial performed by ZMA’s original developers tested ZMA’s effects on muscle strength. This trial used ZMA composed of 30 mg zinc, 450 mg magnesium, and 10.5 mg vitamin B6. Over 8 weeks, this ZMA dosage caused 10% to 15% increases in torque and power in young, highly trained male athletes. However, ZMA did not have any effect on muscle mass.
Another use for ZMA is to increase anabolic hormone levels, including testosterone and IGF-1.
During the initial testing of ZMA, scientists also measured testosterone, free testosterone, and IGF-1 in those taking ZMA. At the conclusion of the study, both total and free testosterone levels had increased by over 30% in those who took ZMA. IGF-1 levels also increased by an average of 3%.
The zinc in ZMA is usually credited with stimulating these hormone increases. According to one study, low zinc levels decrease testosterone while zinc supplementation increases testosterone.
Some athletes use ZMA to restore zinc and magnesium levels. Research shows athletic-induced stress often causes athletes to become deficient in these key minerals.
ZMA is also used as a sleep aid. The magnesium in ZMA is associated with improving sleep quality. Low magnesium levels often occur in those who have difficulty getting to sleep.
Because it contains zinc, ZMA may also boost immunity. Although ZMA has not been specifically tested for this purpose, scientists know zinc plays several key roles in proper immune system function.
Although ZMA contains only essential nutrients, it may still cause side effects.
There are anecdotal reports that ZMA causes vivid, sometimes violet dreams. Scientists are unsure exactly why this side effect occurs. One possible reason is ZMA’s vitamin B6 enhances dream perception. But, vitamin B6 dosages that cause this effect are usually larger than those in ZMA supplements.
The Office of Dietary Supplements at the National Institutes of Health recommends adults take no more than 350 mg supplemental magnesium per day. Magnesium dosages of 350 mg or more sometimes cause diarrhea. Most ZMA formulas contain 450 mg or more of magnesium, so ZMA may induce diarrhea.
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-  ZMA product label. SNAC System, Inc.