ZMA, short for zinc magnesium aspartate, is a popular supplement in the fitness community.
It contains three ingredients: zinc, magnesium, and vitamin B6.
Manufacturers claim ZMA has a variety of health benefits for performance and building muscle mass, which includes increasing testosterone levels. However, research in this area shows mixed results.
This article explains whether ZMA increases testosterone and if it’s safe.
ZMA is a nutritional supplement targeted at athletes, bodybuilders, and fitness enthusiasts.
It contains the following ingredients in varying forms and doses:
- Zinc: as zinc monomethionine, zinc aspartate, or zinc oxide
- Magnesium: as magnesium aspartate, magnesium oxide, or magnesium citrate
- Vitamin B6 (pyridoxine)
Some manufacturers include other vitamins, minerals, or amino acids in their ZMA products, such as vitamin D3, folate, theanine, 5-HTP, valerian root, Tribulus terrestris, melatonin, and various other ingredients.
People take ZMA for various reasons, including to increase testosterone, aid recovery, improve sleep quality, boost immunity, and help with muscle and strength, as manufacturers claim ZMA can help in these areas.
Still, there’s limited research supporting the health and performance benefits of ZMA.
ZMA is a vitamin and mineral supplement containing zinc, magnesium, and vitamin B6. Most people take ZMA to aid muscle recovery and performance, but research in this area is limited.
Many athletes, bodybuilders, and fitness enthusiasts take ZMA to boost testosterone.
However, research on ZMA and testosterone shows mixed results, with some studies indicating it can increase testosterone, while other studies find no effect. It should be noted that most research on ZMA is fairly old and outdated.
An 8-week study from 2000 in 27 college football players observed that taking a ZMA supplement daily significantly increased free testosterone by 33.5% and insulin-like growth factor 1 (IGF-1) levels by 3.6%. Plus, it improved muscle strength and functional power (4).
Still, it should be noted that an author in this study has ownership in the company that manufactured the particular ZMA supplement. Additionally, this company helped fund the study, raising a potential conflict of interest.
Outside of this study, other research did not find that ZMA increases testosterone.
For example, an 8-week study from 2004 in 42 resistance-trained men found that supplementing with ZMA did not increase free or total testosterone. Also, ZMA did not improve exercise performance or body composition (
Similarly, a study in 14 healthy men found that taking a ZMA supplement daily for 56 days did not raise free or total testosterone levels (
Individually, some research suggests that supplementing with zinc may help increase testosterone levels in people with a zinc deficiency or among men with low testosterone levels. Yet, this doesn’t seem to apply to healthy men (
ZMA may increase testosterone in men with a zinc deficiency or low testosterone levels due to its zinc content. However, most research suggests it won’t increase testosterone in healthy individuals.
While most research doesn’t suggest that ZMA will increase testosterone in healthy individuals, it may offer some other benefits.
May improve sleep quality
Many people take ZMA as a sleep aid to improve sleep quality.
This is mostly because of the combination of zinc and magnesium.
Research suggests supplementing with zinc may help improve sleep quality, while magnesium helps activate your parasympathetic nervous system, which helps the brain and body relax before you fall asleep (
Magnesium appears to help regulate melatonin, a hormone that regulates your sleep-wake cycles, and bind to gamma-aminobutyric acid (GABA) receptors, which plays a role in slowing down nerve activity (
An 8-week study in 43 people with insomnia found that taking the combination of zinc, magnesium, and melatonin before bedtime improved sleep quality and reduced the time to sleep, compared with placebo treatment (
May support immunity
Zinc, magnesium, and vitamin B6 have properties that may help support immunity.
Zinc is important for the development of immune cells and healthy cell signaling, so a lack of zinc in the diet may impair your immune system’s response (
Supplementing with magnesium has been shown in studies to reduce inflammatory markers, such as C-reactive protein (CRP), and interleukin 6 (IL-6). Whereas research has linked a magnesium deficiency to chronic inflammation (
However, there are currently no studies on the combination of zinc, magnesium, and vitamin B6 as a supplement to help boost immunity.
The combination of zinc and magnesium in ZMA supplements may help improve sleep quality. Plus, as zinc, magnesium, and vitamin B6 play vital roles in the health of the immune system, supplementing with ZMA may support immune health.
There’s limited research examining the effects of ZMA on testosterone.
Most studies use the following dose, similar to the amounts present in supplements:
- Zinc: 30 mg, or 273% of the Daily Value (DV)
- Magnesium: 450 mg, or 107% of the DV
- Vitamin B6: 10–11 mg, or 588–647% of the DV
Because current research does not clearly show that supplementing with ZMA increases testosterone, more research is needed before it can be recommended for this purpose.
However, ZMA may aid other areas of your health, by improving sleep quality and aiding immunity.
ZMA is available at health food stores, supplement stores, and online. It comes in various forms, including powder and capsules.
Most ZMA supplements are dosed similarly to the amounts listed above. This equates to taking three ZMA capsules or three scoops of ZMA powder for men. However, women are typically advised to take two capsules or two scoops of powder.
Supplement labels recommend taking ZMA on an empty stomach approximately 30–60 minutes before bed. This prevents zinc, magnesium, and vitamin B6 from interacting with other nutrients in your diet.
ZMA supplements typically recommend three capsules or scoops of powder for men and two for women. Avoid taking more than advised on the supplement label.
To date, no studies have reported side effects related to ZMA.
- Zinc: nausea, vomiting, loss of appetite, stomach cramps, diarrhea, and headaches; also, excessive zinc intake may mask a copper deficiency
- Magnesium: diarrhea, nausea, stomach cramps, and vomiting
- Vitamin B6: pain or numbness in the hands or feet, and nerve damage
Still, these side effects aren’t likely at doses listed on the label.
Zinc, magnesium, and vitamin B6 may interact with various medications, such as antibiotics, anti-epileptic drugs, theophylline, bisphosphonates, diuretics (water pills), penicillamine, proton pump inhibitors, and various blood pressure medications (27, 28, 29).
As with all dietary supplements, it’s important to speak with your healthcare provider before taking ZMA, in case of any adverse effects.
ZMA is relatively safe at standard doses, but it may cause side effects at very high doses. As with any dietary supplement, talk with your healthcare provider before taking ZMA.
ZMA is a nutritional supplement containing zinc, magnesium, and vitamin B6.
Research on ZMA and testosterone shows mixed results, but most research suggests ZMA won’t increase testosterone in healthy men. Among men with a zinc deficiency or low testosterone, ZMA may increase testosterone due to its zinc content.
Aside from testosterone, ZMA may enhance sleep quality and aid immunity. These qualities can benefit many individuals, including athletes, bodybuilders, and fitness enthusiasts.
ZMA is generally safe when taken at the recommended dosage. As with any dietary supplement, speak with your healthcare provider before taking ZMA.
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