ZMA Review: How Potent Is The Zinc/Magnesium/Vitamin B6 Trio?

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No question about it, ZMA has the scientific research and real-world anecdotal evidence to launch it to a level previously held only by creatine…Any bodybuilder looking to gain strength, increase athletic performance, and muscle mass should consider taking ZMA.”

Or so the ads tell us…But does ZMA really have as much scientific support and real world results as creatine does?

Well, no…not quite. It’s not even close, really.

What is ZMA?

ZMA is a relatively simple blend, consisting of zinc monomethionine aspartate, magnesium aspartate and vitamin B6. The formula was originally created and marketed by SNAC System Inc—a supplement company founded by Victor Conte (of BALCO fame). It was heavily promoted to bodybuilders on the strength of a single study demonstrating significant increases in testosterone and IGF-1 in collegiate football players.

Effects of a Novel Zinc-Magnesium Formulation on Hormones and Strength

L.R. BRILLA AND VICTOR CONTE
JEPonline, 3(4): 26-36, 2000.

Muscle attributes and selected blood hormones of football players were assessed in response to a nightly supplementation regimen during spring football, over an 8-week period, with pre-post measures. A double-blind randomized study was conducted with ZMA (30 mg zinc monomethionine aspartate, 450 mg magnesium aspartate, and 10.5 mg of vitamin B-6) and placebo (P), n=12 and n=15, respectively. Plasma zinc and magnesium levels were ZMA (0.80 to 1.04 mg/ml; 19.43 to 20.63 mcg/ml ) and P(0.84 to 0.80 mg/ml ; 19.68 to 18.04 mg/ml), respectively (P<0.001). Free testosterone increased with ZMA (132.1 to 176.3 pg/mL),compared to P (141.0 to 126.6 pg/mL) (P<0.001); IGF-I increased in the ZMA group (424.2 to 439.3 ng/mL) and decreased in P (437.3 to 343.3 ng/mL) (P<0.001). Muscle strength via torque measurements and functional power were assessed with a Biodex dynamometer. Differences were noted between the groups (P<0.001): ZMA (189.9 to 211 Nm at 180º/s and 316.5 to 373.7 Nm at 300º/s) and P (204.2 to 209.1 Nm at 180º/s and 369.5 to 404.3 Nm at 300º/s). The results demonstrate the efficacy of a Zn-Mg preparation (ZMA) on muscle attributes and selected hormones in strength-trained, competitive athletes.

According to this study (co-authored by Victor Conte himself), the ZMA supplemented players had increases in total/free testosterone and IGF-1 over an intensive, 8-week training period, vs. decreases in the control group. In addition, strength increases were higher in the ZMA supplemented group.

The Real World…and More Science

Needless to state, this generated a lot of interest in ZMA when it was first released, and hopes were high. Nonetheless, experience with the supplement fell short of expectations. In fact, just a few short years after ZMA’s triumphal debut, a different, independent study conducted at Baylor University concluded:

“Results of the present study do not support contentions that ZMA supplementation increases zinc or magnesium status and/or affects training adaptations in experienced resistance trained males with normal zinc status. These findings are in contrast with the notion that ZMA supplementation can increase zinc and magnesium status, anabolic hormone status, and/or strength gains during training. These findings refute claims that ZMA supplementation in the amount and manner investigated provides ergogenic value to experienced resistance trained athletes.”

What happened? Was there something wrong with the original study? Not necessarily, although to understand why, it will help to know a little more about the theory behind ZMA.

To begin with, zinc and magnesium are both essential minerals that play significant roles in a wide variety of biochemical reactions.

Zinc has important antioxidant, immune and anti-inflammatory activities.

More importantly (at least from a bodybuilding perspective), zinc plays a role in normal reproductive and sexual functions for both men and women.

Deficiencies of both minerals may also result in reduced IGF-1 levels and impaired muscle protein synthesis. Vitamin B-6 is also important for protein metabolism. In addition, animal experiments have shown that the absorption of both zinc and magnesium may be enhanced by vitamin B-6.

Needless to state, a deficiency in any of these three nutrients isn’t good news, for your health as well as your performance in the gym. It’s a different story, however, if your intake is already sufficient. This was supported by a recent study looking at the effects of ZMA in young, exercising men consuming between 11.9 mg and 23.2 mg of the RDA (slightly over 100%–200% of the RDA). ZMA supplementation had no effects on total or free testosterone levels.

All Things Considered…

Does this mean ZMA is useless?

Not necessarily. Dietary surveys have shown that the normal American diet may not always be adequate in zinc and/or magnesium, and intense exercise may further deplete tissue stores of these minerals. Under these circumstances, additional supplementation can be useful. ZMA is likely to be a superior supplemental source as the minerals are chelated to amino acids, which may improve their bioavailability.

In addition, many users report that ZMA helps them get to sleep at night, so there may be reasons to take it beyond correcting possible deficiencies. Thus, while ZMA may not radically improve your hormones or strength, ZMA could be a worthwhile supplement to take. It’s certainly inexpensive and readily obtainable, so feel free to experiment.

There are a wide variety of ZMA products available, including:

Twinlab ZMA Fuel, Ultimate Nutrition ZMA, ProLab ProZMA, NOW ZMA, Primaforce ZMA, Optimum ZMA, SciFit ZMA, SNAC ZMA, Dymatize Z-Force, Kaizen ZMA PM, Muscle Link ZMA-T, ALLMax ZMA and Universal ZMA Pro.

Summary of ZMA
  • Composed of essential nutrients.
  • Some scientific evidence behind it.
  • Inexpensive and easily obtained.
  • Negative studies also exist.
  • No performance benefits in the absence of deficiency.
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