Many athletes, fitness enthusiasts, and bodybuilders use ZMA (which stands for Zinc Magnesium Aspartate) to improve strength and testosterone. ZMA supplements consist of three main ingredients: magnesium, zinc, and vitamin B6.
Many supplement companies claim that ZMA can improve sleep, muscle recovery rates, testosterone levels, endurance, and overall strength. But is this true, or is it just a myth?
7 Potential Benefits of ZMA
- Improves Sleep
- Increases Strength
- Aids Muscle Recovery
- Boosts Testosterone Levels
- Improves Endurance
- Increases Muscle Growth
- Improves Athletic Performance
ZMA and Athletic Performance
There are, at present, just a small number of studies measuring the effectiveness of ZMA on athletic performance. In theory, taking ZMA might enhance performance and endurance in people who have a magnesium or zinc deficiency. If you have a deficiency in one of these minerals, you might experience a reduction in testosterone.
A lot of athletes have low magnesium and zinc levels, which can compromise exercise performance. In most cases, low levels of zinc and magnesium come from strict diets or excessive urination and sweat loss.
An 8-week study published in the Journal of Exercise Physiology followed 27 football players who took a daily ZMA supplement. The study found that taking ZMA created a significant increase in testosterone, functional power, and muscle strength.
However, it’s safe to assume that most football players were deficient in magnesium and zinc at the start of the study. Instead of boosting the football players’ zinc and magnesium levels, taking ZMA restored these micronutrients back to normal levels, which in itself would have a positive effect on performance and strength.
It’s important to note that one of the study authors has ownership in a company that produces ZMA supplements. That company also helped fund the research for the study, so in this case, there is a huge conflict of interest.
Another 8-week study conducted by Baylor University followed 42 men with resistance training experience. This study found that men who consumed a daily ZMA supplement did not increase their insulin-like growth hormone or testosterone levels compared to a placebo supplement. ZMA also failed to improve exercise performance or body composition.
A further study by the German Sport University in Cologne analyzed 14 men who were healthy and did regular exercise. The study found that men who took a daily ZMA supplement for 8-weeks showed no improvement in testosterone levels.
Studies show that when taken as a standalone supplement, magnesium and zinc can raise testosterone levels and reduce muscle fatigue. However, at this stage, it’s not clear if zinc and magnesium have a positive impact on testosterone when taken together.
Safety and Side Effects
A ZMA supplement contains moderate-to-high doses of three ingredients: zinc, magnesium, and Vitamin B6. Research shows that there is a possibility that these nutrients can result in side effects if consumed in high doses.
- Magnesium can cause stomach cramps, diarrhea, vomiting, and nausea.
- Zinc can cause dizziness, headaches, copper deficiency, stomach cramps, loss of appetite, diarrhea, vomiting, and nausea.
- Vitamin B6 can cause numbness and pain in the hands and feet, as well as nerve damage.
While ZMA supplements contain moderate-to-high doses of zinc and magnesium, these doses are not high enough to inflict side effects in most cases. However, if you take medication, you should be aware that magnesium and zinc can interact with blood pressure medication, diuretics, and antibiotics.
The most common dose recommendations for ZMA are as follows:
Zinc: 30 mg, which is more than double the recommended daily intake.
Magnesium Aspartate: 450 mg, which is 110% of the recommended daily intake.
Vitamin B6: 10-11 mg, which is over five times the recommended daily intake.
These doses are equivalent to either three ZMA capsules, or three scoops of ZMA powder. In most cases, ZMA supplements recommend this dose for men and advise women to take just two scoops of powder (or two capsules).
If you’re wondering when you should take ZMA, it’s best to consume ZMA on an empty stomach between a half-hour and an hour before you go to bed. This way, ZMA doesn’t interact with other nutrients, such as calcium, and you get as many benefits as possible out of the supplement.
Effectiveness of ZMA
There is a possibility that ZMA can improve athletic performance and testosterone. However, current research provides mixed results, and the one study that found a positive effect may be compromised.
People often experience a deficiency in magnesium and zinc; in this case, ZMA will be useful. It’s for this reason that ZMA is labeled effective, but not necessary.
Before taking ZMA supplements, it’s better to add more zinc and magnesium-rich foods to your diet. For more magnesium, try eating foods such as soybeans, brown rice, and raw spinach. For more zinc, you can eat foods like cashew nuts, beef, and oysters.
In most cases, if you consume a well-balanced diet and already have optimal levels of zinc and magnesium, ZMA supplements won’t increase your strength and testosterone levels.