Thursday, February 28, 2013

ZMA under the microscope. By Vic Goyaram

ZMA under the Microscope:
Wonder Supplement or Just Another Decent Zinc Formulation?
Researched and composed by Veeraj Goyaram
What is ZMA?
ZMA stands for Zinc, Magnesium and Aspartate and is a patented formulation containing Zinc in the form of Zinc monomethionine/ Zinc aspartate, Magnesium aspartate and Vitamin B6 (Figure 1).
Figure 1: Supplement facts of a ZMA supplement
The monomethionine and aspartate are amino acids to which the minerals Zinc and Magnesium are bound. This binding is called amino acid chelation and the resulting products are called amino acid chelates. This is a term which is often seen on supplement labels, especially mineral supplements. Chelation is simply a procedure to improve the absorption and availability of the mineral. The presence of the amino acid with the mineral molecule renders the latter less prone to absorption inhibitors. 

Zinc and Testosterone levels
ZMA, as most of you already know, is sold as a testosterone booster supplement either by itself or as part of products marketed as testosterone boosters (Figure2).  ZMA capitalises on the known link between deficiency of zinc in the male body and reduced testosterone levels. This link was first established in the early 60s by Prasad et al. (1963). The actual mechanism became clear subsequently when it was found that Zinc deficiency impairs the production of testosterone by reducing the action of important hormonal signals in testosterone production like Luteinizing hormone, follicle stimulating hormone and gonadotropin-releasing hormone.
Figure 2: ZMA is marketed as a testosterone booster supplement (A)  either
by itself in ZMA-only products or product formulations (B)containing 
other ingredients that are supposed to increase testosterone production
ZMA came into limelight in the year 2000 at the same time that a study by Brilla and Conte (2000) showed that semi-professional athletes who consumed ZMA experienced a 30% increase in testosterone and an accompanying increase in muscle strength compared to athletes who did not take any ZMA. As a side-note, this study compared ZMA to a placebo rather than also including another group that supplemented with another zinc formulation in order to see whether ZMA is superior to any other zinc formulation. 

It is interesting to note that one of the two authors of this article, Victor Conte (Figure 3) is the founder of BALCO Labs of steroid scandal fame. Conte also owns SNAC systems, the company commercialising the product. The publication of the Brilla and Conte (2000) paper really helped business. 
Figure 3: Victor Conte of BALCO labs fame with his flagship product, ZMA 
Failure of ZMA to increase testosterone levels
Unfortunately, many studies conducted afterwards using ZMA did not find any increase in testosterone. For example, a study by Wilborn et al. (2004) tested ZMA in resistance-trained males aged between 27-28 for 8 weeks. ZMA supplementation increased blood zinc levels by 11-17%.  However, they did not find any significant difference between the levels of anabolic and catabolic hormones, strength, endurance and anaerobic capacity.  

Another study was conducted by German researchers (Koehler et al., 2009) in actively exercising men aged 22-33 yrs who are already consuming enough zinc on a daily basis (11.9-23.2mg/day) within the RDA range (9-11mg). They found no change in serum total and free testosterone with ZMA supplementation, suggesting that ZMA has no significant effects regarding serum testosterone in people who consume a zinc-sufficient diet.

Is Zinc supplementation of any help then?
The answer is yes but only under conditions of Zinc deficiency which is something not difficult to develop. Zinc deficiency not only impairs testosterone production but also leads to problems like growth abnormalities, mental lethargy, delayed wound healing and impaired activities of zinc-dependent enzymes which play very important roles in the body. Under these conditions zinc supplementation definitely help.

What bring about zinc deficiency are factors like:
  • High phytate content of the diet. Phytate is present in the hull of seeds, nuts and grains. It is indigestible and is able to complex minerals, namely Iron and Zinc which are then not available for absorption. My undergraduate degree  dissertation was in the field of human mineral nutrition (details in reference section) and I looked extensively at the disadvantages of diets rich in phytates that may lead to mineral deficiency.
  • Alcoholism, leading to urinary zinc excretion.
  • Liver and renal disease.
  • Exercise?
Exercising individuals are at great risk of developing zinc deficiency as plasma zinc levels have been shown to decline with acute stress such as exercise (Volpe, 2012) thereby creating a need for ensuring adequate zinc intakes. Food sources are excellent for this (Figure 4). In a study conducted in wrestlers it was found that exhaustion exercise led to a significant reduction of zinc levels which led to decreased testosterone and thyroid hormones. However, a 4-week zinc supplementation program rescued this effect (Kilic et al., 2006). Therefore, zinc supplementation increases testosterone if you are deficient in zinc.

However, even if you are actively exercising taking extra zinc when you are already getting sufficient amounts in the diet will be of no further help (Koehler et al., 2009).  You can turn to food rather than jump on supplement mega-doses. Taking too much zinc, for instance, potentially has urinary alkalising and diuretic effect and can negatively impact on the absorption of other minerals like Iron (competitive mineral absorption) (Veeraj Goyaram BSc Hons thesis, 2004) 
Figure 3: some good dietary sources of Zinc (Volpe et al., 2012)
ZMA and sleep quality
There are many anecdotal reports that intake of ZMA and Zinc-Magnesium formulations help improve sleep quality. Studies also found that zinc and magnesium supplementation improves sleep quality although these studies did not use ZMA (Rondanelli et al., 2011). I have personally taken a Cal-Mag-Zinc mineral combo during my early bodybuilding heydays with good result. 

The take-home message
  • Zinc is important for many body function and a deficiency of zinc can lead to, among others, low testosterone levels.
  • Athletes can develop zinc deficiency and must consume foods that provide zinc.
  • ZMA has not been proven to increase testosterone. Likewise zinc supplementation is not proven to increase testosterone further when zinc intakes were already adequate.
  • You can obtain zinc from food sources and cheaper supplemental sources (e.g Zinc gluconate) rather than the patented, and therefore expensive, ZMA.
  • If you have money, buy ZMA. But remember taking extra zinc if testosterone levels and zinc intake are normal will not lead to higher testosterone. There are tests that can be done to check whether you are zinc deficient. 


Brilla LR and Conte V (2000). Effects of a novel zinc–magnesium formulation on hormones and strength. JEPonline 3, 26–35.

Goyaram, V. (2004). Determinants of Bioavailability in Human Iron Nutrition: Ascorbic Acid as a Knight in Shining Armour. Dissertation in partial fulfillment of the degree of BSc (Hons) in Biology, University of Mauritius, Reduit, Mauritius. 

Kilic M, Baltaci AK, Gunay M, Gökbel H, Okudan N, Cicioglu I. The effect of exhaustion exercise on thyroid hormones and testosterone levels of elite athletes receiving oral zinc. Neuro Endocrinol Lett. 2006 Feb-Apr;27(1-2):247-52.

Koehler K, Parr MK, Geyer H, Mester J, Schänzer W.Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement. Eur J Clin Nutr. 2009 Jan;63(1):65-70.

Prasad AS, Miale A, Farid Z, Schulert A, Sandstead HH (1963). Zinc metabolism in patients with the syndrome of iron deficiency anemia, hypogonadism and dwarfism. J Lab Clin Med 61, 537–549

Rondanelli M, Opizzi A, Monteferrario F, Antoniello N, Manni R, Klersy C.The effect of melatonin, magnesium, and zinc on primary insomnia in long-term care facility residents in Italy: a double-blind, placebo-controlled clinical trial. J Am Geriatr Soc. 2011 Jan;59(1):82-90.

Volpe, Stella Lucia. Minerals as Ergogenic Aids. Current Sports Medicine Reports. 7(4):224-229, July/August 2008.

Wilborn CD, Kerksick CM, Campbell BI, Taylor LW, Marcello BM, Rasmussen CJ, Greenwood MC, Almada A, Kreider RB. Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training Adaptations and Markers of Anabolism and Catabolism. J Int Soc Sports Nutr. 2004 Dec 31;1(2):12-20.

My Bio: I am a Mauritian originally from Roche Bois, Port Louis and have been calling Cape Town, South Africa home since 2010 when I came to follow my passion for performance nutrition and nutritional supplements. I studied at the University of Cape Town at the UCT Research Unit of Exercise Science & Sports Medicine then under the leadership of Professor Tim Noakes. I came to South Africa with nothing and thus had to work my way through university by working shifts in pharmacies and supermarkets merchandising and selling nutritional supplements every day after school and every weekend. I had a great time doing this work even for a full year following my cum laude MSc graduation. My university research looked at the influence of nutrition and exercise on the function of genes in muscle, research which is relevant and applicable to exercising individuals, sports persons and diabetic individuals. The knowledge that I share with you stems from my 18 years of experience in bodybuilding and 7 years university education in the field. I have also published work in the American Journal of Physiology: Endocrinology and Metabolism (2013), International Journal of Sport Nutrition and Exercise Metabolism (2013) and co-authored two book chapters on exercise and diabetes. I also presented my research work at the 2012 International Sports and Exercise Nutrition Conference (UK) and the 2013 Physiological Society of Southern Africa conference. I now serve as Director of Research & Development for Functional Nutrition International Pty. Ltd, an avant-garde nutritional supplements company based in Cape Town. 
©,2013, Veeraj Goyaram, Bodybuilding Mauritius. Any reprinting in any type of media is prohibited.
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