ZMA (supplement)

ZMA (Zinc monomethionine aspartate and Magnesium Aspartate) is a supplement used by bodybuilders and athletes. It was developed by Victor Conte (founder of BALCO Laboratories in Burlingame, California) and is a combination of zinc, magnesium and vitamin B6. The name "ZMA" is 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. All three of these compounds are important in biological processes, and while studies have shown that most Americans get enough zinc and vitamin B6,[1] more than 50% don't meet the U.S. government's recommendation for magnesium.[2]

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.[3]

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.[4] 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 football 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 in this company.

References

  1. ^ "Ohio State University Extension Fact Sheet". http://ohioline.osu.edu/hyg-fact/5000/5560.html. Retrieved 2006-08-11. 
  2. ^ "More than half of Americans don’t get nearly enough magnesium" (PDF). http://www.longislanddiabetes.org/Microsoft%20Word%20-%20Nutrient%20Gap%20for%20ADA.pdf. Retrieved 2006-08-11. 
  3. ^ Wilborn, Colin D; Kerksick, Chad M; Campbell, Bill I; Taylor, Lem W; Marcello, Brandon M; Rasmussen, Christopher J; Greenwood, Mike C; Almada, Anthony et al. (2004). "Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training Adaptations and Markers of Anabolism and Catabolism". Journal of the International Society of Sports Nutrition 1 (2): 12–20. doi:10.1186/1550-2783-1-2-12. PMC 2129161. PMID 18500945. http://www.jissn.com/content/1/2/12. 
  4. ^ Koehler, K; Parr, M K; Geyer, H; Mester, J; Schänzer, W (2007). "Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement". European Journal of Clinical Nutrition 63 (1): 65–70. doi:10.1038/sj.ejcn.1602899. PMID 17882141. http://www.nature.com/ejcn/journal/v63/n1/abs/1602899a.html.