The Myth (?)
ZMA (Zinc Magnesium Aspartate) is well known and widely used ‘ergogenic’ supplement that is thought to significantly improve muscle strength along with concentrations of total testosterone, free testosterone and insulin-like growth factor (Brilla & Conte, 2000).
The Reasoning:
It is known that deficiencies of zinc and magnesium aspartate decrease both testosterone and IGF-1. Simultaneously, athletes are reported to have lower levels of these minerals which possibly occurs due to increased sweating and inadequate intake in their diets. By this logic, supplementation with zinc and magnesium should raise the serum levels of these minerals, thereby enhancing the anabolic hormonal profiles of athletes and improving adaptations to resistance training.
The Facts:
To date, only one study has found a positive effect of ZMA on muscle strength and IGF-1 (Brilla & Conte, 2000). The International Society of Sports Nutrition reports that it is yet unknown whether Zinc/Magnesium Aspartate is effective in muscle building, and it certainly appears that clear proof to this effect is currently lacking. For example, an 8-week study of 42 resistance-trained males saw no significant ergogenic improvements following supplementation (Wilborn, et al., 2004). Another investigation into the effects of ZMA on serum testosterone and urinary excretion of steroid hormone metabolites found, similarly, that ZMA had no significant effects on these hormones (Koehler, et al. 2009).
The Conclusion:
Supplementation with ZMA at recommended doses does not appear to result in any adverse effects. However, more research is needed to determine whether this supplementation enhances training adaptations in resistance trained populations. Companies reporting that their ZMA product may provide increases to testosterone, etc. are likely citing the work of Brilla & Conte (2000), while ignoring the remaining studies which were unable to find any significant ergogenic benefits. Whether you invest in ZMA or not, the choice is ultimately up to you. You should be aware that the research is currently stacked against ZMA in terms of its purported benefits, and (in terms of supplements to aid recovery & lean mass accrual). As for me, I would turn to a host of other products including EFA’s, Vitamin D & Creatine before spending money on a more ‘exotic’ product such as ZMA.
References:
Brilla, L.R., Conte, V. (2000). Effects of a novel zinc-magnesium formulation on hormones and strength. J Exerc Physiol Online; 3:26-36.
Koehler, K., Parr, M. K., Geyer, H., Mester, J., & Schanzer, W. (2009). Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement. European Journal of Clinical Nutrition, 63, 65-70.
Wilborn, C. D., Kerksick, C. M., Campbell, B. I., Taylor, L. W., Marcello, B. M., Rasmussen, C. J., Greenwood, M. C., Almada, A., & Kreider, R. B. (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, doi: 10.1186/1550-2783-1-2-12
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