Recently, in Recover and Get Stronger With ZMA, we went over the benefits of zinc magnesium aspartate (ZMA) as a nighttime aid to recovery after very strenuous workouts.
Two studies have just been posted on the ISSN forums refuting the claims of serum testosterone increase while using ZMA. The abstracts follow and you can decide for yourself if ZMA is something you want to use in your recovery arsenal. (Anecdotally, I sleep deeper when take it and wake up refreshed). I probably will continue to take it on my heaviest lifting days.
These were originally posted on Supertraining by “carruthersjam”.
Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement
European Journal of Clinical Nutrition (2009) 63, 65?70;
doi:10.1038/sj.ejcn.1602899; published online 19 September 2007
Abstract
Objectives:
To investigate whether the administration of the zinc-containing
nutritional supplement ZMA causes an increase of serum testosterone
levels, which is an often claimed effect in advertising for such
products; to monitor the urinary excretion of testosterone and
selected steroid hormone metabolites to detect potential changes in
the excretion patterns of ZMA users.
Subjects:
Fourteen healthy, regularly exercising men aged 22?33 years with a
baseline zinc intake between 11.9 and 23.2 mg day-1 prior to the
study.
Results:
Supplementation of ZMA significantly increased serum zinc (P=0.031)
and urinary zinc excretion (P=0.035). Urinary pH (P=0.011) and urine
flow (P=0.045) were also elevated in the subjects using ZMA. No
significant changes in serum total and serum free testosterone were
observed in response to ZMA use. Also, the urinary excretion pattern
of testosterone metabolites was not significantly altered in ZMA
users.
Conclusions:
The present data suggest that the use of ZMA has no significant
effects regarding serum testosterone levels and the metabolism of
testosterone in subjects who consume a zinc-sufficient diet.
Keywords:
zinc supplementation, athletes, serum testosterone, urinary steroid
hormone metabolites, urinary zinc excretion
Here is the second:
Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training
Adaptations and Markers of Anabolism and Catabolism
Colin D Wilborn1, Chad M Kerksick1, Bill I Campbell1, Lem W Taylor1,
Brandon M Marcello1, Christopher J Rasmussen1, Mike C Greenwood1,
Anthony Almada2 and Richard B Kreider1
Journal of the International Society of Sports Nutrition 2004, 1:12-
20doi:10.1186/1550-2783-1-2-12
Abstract
This study examined whether supplementing the diet with a commercial
supplement containing zinc magnesium aspartate (ZMA) during training
affects zinc and magnesium status, anabolic and catabolic hormone
profiles, and/or training adaptations. Forty-two resistance trained
males (27 ± 9 yrs; 178 ± 8 cm, 85 ± 15 kg, 18.6 ± 6% body fat) were
matched according to fat free mass and randomly assigned to ingest in
a double blind manner either a dextrose placebo (P) or ZMA 30?60
minutes prior to going to sleep during 8-weeks of standardized
resistance-training. Subjects completed testing sessions at 0, 4, and
8 weeks that included body composition assessment as determined by
dual energy X-ray absorptiometry, 1-RM and muscular endurance tests
on the bench and leg press, a Wingate anaerobic power test, and blood
analysis to assess anabolic/catabolic status as well as markers of
health. Data were analyzed using repeated measures ANOVA. Results
indicated that ZMA supplementation non-significantly increased serum
zinc levels by 11 ? 17% (p = 0.12).
However, no significant differences were observed between groups in
anabolic or catabolic hormone status, body composition, 1-RM bench
press and leg press, upper or lower body muscular endurance, or
cycling anaerobic capacity. Results indicate that ZMA supplementation
during training does not appear to enhance training adaptations in
resistance trained populations.
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