ZMA is a scientifically designed anabolic vitamin and mineral
formula. It specifically contains Zinc Monomethionine Aspartate,
Magnesium Aspartate, and vitamin B-6. It is an all-natural product
that has been theorized to significantly increase anabolic hormone
levels and muscular strength in trained athletes. In fact, ZMA
is thought to be one of the only natural and completely safe
methods of supplementation to significantly increase testosterone
and growth hormones. ZMA has also been known to increase muscle
mass, strength, power, and even enhances sleep quality. However,
there have been relatively few studies performed on ZMA since
its inception into the supplement industry.
The most talked about and significant study on ZMA is the following
by Brilla et al (23) at Washington University. This study reported
that ZMA significantly increased free testosterone levels and
muscle strength in NCAA football players. Specifically, Brilla
reported that a group of competitive NCAA football players who
took ZMA nightly during an eight-week spring training program
had 2.5 times greater muscle strength gains than a placebo group.
In practical terms, this means that if the placebo group improved
by only 20 pounds, the ZMA group would improve by 50 pounds.
Overall, the strength of the ZMA group increased by 11.6% compared
to only a 4.6% increase in the placebo group.
Brilla (23) went on to further say, "The muscle strength
increases may have been mediated by the anabolic hormone increases
in the ZMA group. The ZMA group had 30% increases in free and
total testosterone levels compared to 10 percent decreases in
the placebo group. The ZMA group also had a slight increase in
insulin-like growth factor-1 (IGF-1) levels compared to a 20
percent decrease in the placebo group. This study shows that
anabolic hormone and muscle strength increases can be induced
in already strength-trained athletes by using a novel zinc-magnesium
preparation." Although it has been debated as to how certain
hormonal changes take place such as IGF-1, it appears there are
specific mechanisms in ZMA that may trigger physiological changes
associated with elevating hormonal responses.
Another benefit commonly associated with ZMA is better sleep
(24). Typically, ZMA should be taken 30 - 60 minutes before bed.
Although not clinically proven, it has been noted that most people
supplementing with ZMA noticed better sleep patterns and a deeper
sleep which may directly and indirectly affect athletic performance.
While zinc and magnesium deficiencies are common in the general
population, deficiencies of these minerals are even more prevalent
in athletes. Research shows that intense exercise and stress
related physical activity results in relatively high levels of
bodily losses of zinc and magnesium. Furthermore, in 1998, BALCO
Laboratories tested the mineral status of over 250 NFL players,
including the entire Denver Broncos Super Bowl championship team,
as well as the entire Miami Dolphins team. The results showed
that over 70% of the football players were either depleted or
deficient in both zinc and magnesium (25).
The dosage and proportion is very important. A common multi-vitamin
will not produce these results. Most successful ZMA products
have: Vitamin B6: 11mg, Magnesium: 450mg, Zinc: 30mg. This product
is all-natural and there are no known side effects. It is safe
for men and women. Because of the limited studies done on this
supplement, much more research is needed to clarify all based
conclusions in regards to ZMA.
Summary and Recommendation
There is currently very little research and evidence found
for ZMA supplementation. Although the supplement receives critical
acclaim from the bodybuilding industry and many athletes, there
lacks sufficient scientific studies to fully condone ZMA supplementation.
The few studies that have been performed on ZMA, such as those
previously described, have favorable conclusions and results
that support ZMA. It appears ZMA increases strength, growth hormone
levels, testosterone, muscle mass, IGF-1 levels, and enhanced
Dosage recommendations for ZMA seem to be very inconclusive.
In fact, consumerlab.com does not have any recommendations in
regards to ZMA. However, most successful ZMA products have: Vitamin
B6: 11mg, Magnesium: 450mg Zinc: 30mg. It appears that the ratio
of the three substances found in ZMA is very critical for its
maximum potency. It is typically recommended that ZMA is taken
before sleep on an empty stomach in the same dosage recommendations
as stated above. However, certain companies encourage double
to triple that dosage as long as the ratio is kept constant.
Whether this is an advertising ploy by the companies to sell
more of the product or simply a positive performance enhancement,
formula has yet to be determined by proper scientific studies.
It is currently believed that there is no toxicity associated
with ZMA, however, very little research in this specific area
According to consumerlab.com and other valid sources, some of
the best ZMA products are manufactured by the following companies:
Beverly, Optimum Nutrition, PrimaForce, Dymatize, ISS, Prolab,
Ultimate Nutrition, Twinlab, and Universal.
23. Brilla, L. Effects of zinc-magnesium (ZMA) supplementation
on muscle attributes of football players. ACSM journal, Medicine
and Science in Sports and Exercise, Vol.31, No. 5, May 1999.
24. Bodybuilding.com. ZMA Info and Products. 2006.
25. Conte, V. The Natural Alternative to Prohormones. Fitness
Matters- maxmuscle.com. 2006.