Does ZMA Work?

May 20th, 2008 by Paul Johnson

ZMA is a proprietary trademark blend, developed by Victor Conte of Balco Labs, based on research studies. It was developed to increase testosterone and muscular strength.

How ZMA works

ZMA is zinc, magnesium and B6. Zinc appears to have a strong role in regulating testosterone levels, by blocking the conversion of testosterone to DHT, through the 5A Reductase enzyme. Magnesium is a important neurological mineral and has been shown in past studies to improve strength. Vitamin B6 helps with zinc's inhibitory action on the 5A reductase enzyme.

ZMA Studies

The original study on ZMA was founded by the Victor Conte. He had NCAA football athletes stop taking nutritional supplements for 8 weeks. The control group took ZMA and their lean muscle, strength, and serum testosterone levels were monitored. ZMA supplementation iincreased the leg strength by 11.5% over 4.9% of the placebo. There was an increase of 30% in free and total testosterone (vs 10% in the placebo), and an increase of 20% in IGF-1 levels (vs a 20% decrease in placebo). Results of the study did not show any changes in lean muscle gains despite the anabolic changes.

A study published in (Journal of the International Society of Sports Nutrition 1 (2): 12-20. doi:10.1186/1550-2783-1-2-12) showed 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 during 8 weeks of ZMA supplementation.

A recent ZMA study published in (European Journal of Clinical Nutrition advance online publication, 19 September 2007; doi:10.1038/sj.ejcn.1602899) 14 subjects in their 20s through 30's excercised regularly and took 11 to 22 mg of zinc a day, before the study started. When the study started, they took the recommended doses of ZMA and measured their urine for testosterone and other metabolites and their serum testosterone levels. Results showed no difference in free or total testosterone serum levels or in changes in urine excretion patterns of testosterone and it's metabolites. Serum zinc levels and excretion in urine were heightened.


The only study that shows ZMA works, was the original funded by the developer of ZMA. ZMA probably only works if you are deficient in magnesium or zinc. Zinc appears to be excreted after excercise, so bodybuilders may require slightly more to offset their active lifestyle. This doesn't point to the efficacy of ZMA as being anything special, just that some may benefit from ZMA because they are already deficient. If you have a really good multi-vitamin with a easily absorbable form of zinc (something other than zinc oxide), it should be adequate zinc intake.

  1. jack on January 5th, 2010

    God, I am so divided on this one. I’ve now read about 50 websites about zma, and I still don’t know what to think.

    I wish people could come to a consensus. I would say half of the reviews I’ve read say it works and the other half say it’s crap. I guess I will just have to try it and decide for myself.

  2. admin on March 3rd, 2010

    If your deficient in zinc or magnesium its great. The thing is calcium in meals interferes with zinc and magnesium absorption and most multivitamins have poor forms of zinc and magnesium (oxide) so some are deficient for those reasons. ZMA is a cheap insurance to make sure your getting enough.

  3. Jerry Bruton on July 15th, 2010

    Thanks for the review on ZMA. I tried ZMA based on the first study. My experience with ZMA was disappointing. I should have read the 2007 study.
    I put ZMA in the same group as NO supplements to avoid buying. Spend the money on protein and creatine.