Zinc-Magnesium Supplementation, Hormones and Strength
Journal of Exercise Physiology
Official Journal of The American
Society of Exercise Physiologists (ASEP)
An International Electronic Journal
Volume 3 Number 4 October 2000
Effects of a Novel Zinc-Magnesium Formulation on Hormones and Strength
AND VICTOR CONTE
Exercise and Sports Science Laboratory, Western Washington University, Bellingham, WA
BALCO Laboratories, 1520 Gilbreth Road, Burlingame, CA 94010, Tel: 800-777-7122
L.R. BRILLA AND VICTOR CONTE.
Effects of a Novel Zinc-Magnesium Formulation on Hormones and
, 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
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
19.43 to 20.63 mcg/ml
) and P
(0.84 to 0.80
; 19.68 to 18.04
g/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.
Key Words: vitamin B
, anabolic hormones, testosterone, IGF-I, muscle
Zinc (Zn) and magnesium (Mg) may enhance levels of Insulin-like Growth Factor-I (IGF-I)(1); and
zinc, in particular, may contribute to elevating serum testosterone (2).
Both IGF-I and testosterone are
anabolic factors that enhance muscle function and physical performance.
Testosterone's role in physical
performance enhancement has been studied for a number of years. The IGF-I response to intense
muscular activity has not been well defined, relatively. Training may lead to a short-term catabolic state
hormonally expressed by reductions in IGF-I. Baseline serum concentrations of testosterone, GH, and
IGF-I were unaffected by 16-wk resistive training program which elicited an approximate 40% increase
in muscular strength in men, 60
It was intimated that training-induced increases in IGF-I could
occur in muscle without altering serum IGF-I concentration (3).
A condition named somatopause due to decreased IGF-I and GH has been identified with aging.
countermeasure somatopause, 33 moderately obese women (67.1
5.2 yr), self-injected IGF-I. Weight
loss with muscle strength increases were greater in IGF-I group due to training (12-wk: walk 3 days,