Why ZMA Supplements Are Overrated

ZMA is a patented combination of Zinc, Magnesium, and Vitamin B6 which was originally developed by SNAC Systems in the late 1990’s and marketed primarily as a Testosterone Booster. The specific forms used in the original formula (still used today) are Zinc Monomethionine and Aspartate, Magnesium Aspartate, and Pyridoxine HCL (Vitamin B6).

Today, ZMA is sold by virtually all of the big name supplement companies, each claiming similar benefits most of which pertain to increasing Testosterone. However, a simple review of the scientific research conducted on ZMA over the years paints a different picture.

How It All Started

In a 1998 study, researchers sought to determine whether ZMA had any effect on strength and testosterone in athletes undergoing rigorous training. The group taking ZMA showed roughly 11% increases in strength, compared to a roughly 5% increase in the placebo group. The ZMA group also showed a roughly 30% increase in Testosterone, compared to a roughly 10% increase in the placebo group.

Well, there you have it! ZMA boosting strength and Testosterone significantly in athletes! Oh wait…we forgot to mention that one of the researchers in the study was Victor Conte, the creator of ZMA and equity holder in SNAC Systems, the company which owns the patent.

Suddenly that study seems a kind of shady. Luckily, because of ZMA’s massive rise in popularity after the data from the study was released, further studies took place. However, these studies were not so encouraging…

Later ZMA Research

A study published in the “Journal of the International Society of Sports Nutrition” in 2004 sought to replicate the findings of the study mentioned above. Researchers in this study (who weren’t equity holders in SNAC this time) found absolutely no influence on Testosterone, strength, endurance, or body composition in resistance-trained males taking ZMA daily for 8 weeks.

Another study, published in the “European Journal of Clinical Nutrition”, also failed to find any influence of ZMA supplementation on Testosterone levels in male subjects, despite increases in circulating and urinary zinc levels.

So, Does ZMA Boost Testosterone?

If we take a step back and look at the research on ZMA and Testosterone as a whole, what we have is one study with a massive conflict of interest showing some unbelievable results, and two later studies with no conflicts of interest failing completely. The facts are pretty clear…

ZMA does not boost Testosterone.  That said, if we take a look at the individual components of ZMA, Zinc and Magnesium, we can see that it may serve a purpose afterall, aleit not one that pertains to everyone.

Zinc And Testosterone

Although Zinc has failed to increase Testosterone levels in individuals with sufficient dietary Zinc intake, it has actually been shown to preserve Testosterone levels in athletes undergoing rigorous training, when a drop in Testosterone would normally occur (and did occur in the placebo group). This has been replicated elsewhere as well.

It’s important to understand though, that preventing a decline in Testosterone and “boosting” Testosterone are two very different things.

The average person who eats a relatively balanced diet full of Zinc-rich foods is not going to experience any noticeable increase in Testosterone, but if you train hard and often you may want to consider throwing some Zinc into the mix.  To learn more about the relationship between Zinc and Testosterone, check out this article.




OptiZinc is Zinc Monomethionine, the same form of Zinc used in the original ZMA formulation.  Although there is no research indicating that this form is better than other forms, it has been shown to be well absorbed upon orla ingestion so it’ll get the job done.

Source Naturals OptiZinc also contains a small amount of Copper.  High doses of Zinc over time may deplete Copper, so it is generally recommend to keep an eye on Copper intake while supplementing with Zinc.

Magnesium and Testosterone

Studies regarding the influence of Magnesium on Testosterone are scarce, but one study did show a slight Testosterone increase in exercising subjects consuming magnesium compared to non-exercising subjects consuming magnesium. However, the increases in total and free Testosterone in this study were pretty marginal, and certainly not enough to enhance muscle growth.

A minor, but not stastically significant increase in Testosterone has been noted in a separate study as well. Looking at the research as a whole, it appears as though Magnesium supplementation may help normalize Testosterone levels but will not outright increase Testosterone to any significant degree.

As with Zinc, the average person isn’t going to experience a Testosterone boost from Magnesium supplementation, but those who exercise regularly and rigorously may want to consider taking Magnesium to maintain optimal Testosterone levels.


Dr's Best Magnesium


Doctor’s Best High Absorption Magnesium is chelated which means it is bound to amino acids (in this case Glycine and Lysine) which improves absorption more so than ordinary elemental Magnesium.

Each serving provides 200mg, or roughly half the RDI for Magnesium, which is safer than many other Magnesium supplements which deliver extremely high (and unncessary) doses.

You don’t need 800% of the RDI, 50-100% will pick up the slack in your diet just fine.

When To Consider Taking ZMA

ZMA has no inherent Testosterone-boosting power, but it is a convenient way to supplement Zinc and Magnesium. So, if you are at risk for deficiency for both Zinc AND Magnesium, ZMA may be the way to go. Just understand that you won’t be “boosting” your Testosterone, you’ll be preserving it by correcting a deficiency.


Optimum Nutrition ZMA


If you want to take a ZMA Supplement, don’t be fooled into takings some over-priced designed brand that claims unrealstic benefits, just go with the basics.

Optimum ZMA is an economical and straight-forward option for individuals who train extremely hard and want to ensure adequate levels of Zinc and Magnesium.


The Bottom Line

ZMA isn’t completely worthless as a supplement, but the benefits have certainly been exaggerated by the mainstream supplement industry, in some cases quite considerably. For athletes and bodybuilders undergoing seriously exhaustive training on a regular basis, ZMA can be effective for encouraging optimal Testosterone levels, but this is a preservation, not a “boost” like most companies claim. The same benefits can be obtained through supplementation with either Zinc or Magnesium seperately as well.


  1. Koehler, K., et al. “Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement.”European journal of clinical nutrition 63.1 (2009): 65-70.
  2. Wilborn, Colin D., et al. “Effects of zinc magnesium aspartate (ZMA) supplementation on training adaptations and markers of anabolism and catabolism.” J Int Soc Sports Nutr 1.2 (2004): 12-20.
  3. Brilla, L. R., and Victor Conte. “Effects of a novel zinc-magnesium formulation on hormones and strength.” J Exerc Physiol Online 3.4 (2000): 26-36.
  4. Brilla, Lorraine R., and Timothy F. Haley. “Effect of magnesium supplementation on strength training in humans.” Journal of the American College of Nutrition 11.3 (1992): 326-329.
  5. Cinar, Vedat, et al. “Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion.”Biological trace element research 140.1 (2011): 18-23.
  6. Neek, Leila Shafiei, Abas Ali Gaeini, and Siroos Choobineh. “Effect of zinc and selenium supplementation on serum testosterone and plasma lactate in cyclist after an exhaustive exercise bout.” Biological trace element research 144.1-3 (2011): 454-462.
  7. Koehler, K., et al. “Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement.” European journal of clinical nutrition 63.1 (2009): 65-70
  8. Kilic, Mehmet, et al. “The effect of exhaustion exercise on thyroid hormones and testosterone levels of elite athletes receiving oral zinc.” Neuro endocrinology letters 27.1-2 (2005): 247-252.
  9. Om AS, Chung KW. Dietary zinc deficiency alters 5 alpha-reduction and aromatization of testosterone and androgen and estrogen receptors in rat liver. J Nutr. (1996) exists to educate the supplement community and seperate the science from the hype.

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