ZMA (Zinc monomethionine aspartate and Magnesium Aspartate) is a supplement used by bodybuilders

Bodybuilding

Bodybuilding is a form of body modification involving intensive muscle hypertrophy. An individual who engages in this activity is referred to as a bodybuilder. In competitive and professional bodybuilding, bodybuilders display their physiques to a panel of judges, who assign points based on their...

 and athletes. It was developed by Victor Conte

Victor Conte

Victor Conte is a former musician with Tower of Power and founder and president of BALCO, a sports nutrition center in California. He served time in prison in 2005 after pleading guilty to conspiracy to distribute steroids and money laundering....

 (founder of BALCO Laboratories

Balco

Balco can refer to:* the Bay Area Laboratory Co-operative - a controversial sports medicine/nutrition centre in Burlingame, California.* Balco balcony systems who develops, designs and manufactures balcony systems and glazing solutions....

 in Burlingame, California

Burlingame, California

Burlingame is a city in San Mateo County, California. It is located on the San Francisco Peninsula and has a significant shoreline on San Francisco Bay. The city is named after diplomat Anson Burlingame. It is renowned for its many surviving examples of Victorian architecture, its affluence, and...

) and is a combination of zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

, magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 and vitamin B₆

Vitamin B6

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Several forms of the vitamin are known, but pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation...

. The formula is "patent pending" and the name "ZMA" trademarked by SNAC System Inc. ZMA claims to raise strength levels, though independent studies do not support this claim.

ZMA is a combination of two minerals, zinc and magnesium, and vitamin B₆ or pyridoxine

Pyridoxine

Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.-Chemistry:...

. All three of these compounds are important in biological processes, and while studies have shown that most Americans get enough zinc and vitamin B₆, more than 50% don't meet the U.S. government's recommendation for magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

.

The proportion of ingredients generally used in products is 20–30 mg zinc, 400–500 mg magnesium and ~10 mg B₆. According to the label directions, ZMA should be taken before bed on an empty stomach (2 hours after eating your last meal and at least 30 minutes prior to any other supplements). The product should not be taken with calcium (cheese, milk, etc.), the reason being that calcium blocks the absorption of zinc.

Scientific studies

In 2004, a study funded by a research grant from Cytodyne (another supplement producing company) with 42 resistance trained males showed that ZMA supplementation had no significant effects on total and free testosterone, IGF-1, growth hormone, cortisol, the ratio of cortisol to testosterone, or muscle and liver enzymes in response to training. No significant effects were observed in changes in strength, upper or lower body muscle endurance, or anaerobic sprint capacity.

In another study done in 2006, a team of German scientists conducted a study on the effect of ZMA and testosterone levels in the body. The result showed an increase in zinc secretions in urine making it much darker like blood, but no effect on the level of testosterone in the body.

A 1998 study was undertaken on NCAA

National Collegiate Athletic Association

The National Collegiate Athletic Association is a semi-voluntary association of 1,281 institutions, conferences, organizations and individuals that organizes the athletic programs of many colleges and universities in the United States...

 football

College football

College football refers to American football played by teams of student athletes fielded by American universities, colleges, and military academies, or Canadian football played by teams of student athletes fielded by Canadian universities...

 players during an 8 week spring training program. The control group was told to cease taking any nutritional supplements. Those who took the ZMA tablets claimed greater increases in muscle strength. This study was funded by SNAC Systems, the patent holder, and one of the study's authors, Victor Conte, has ownership equity

Ownership equity

In accounting and finance, equity is the residual claim or interest of the most junior class of investors in assets, after all liabilities are paid. If liability exceeds assets, negative equity exists...

in this company.