ZMA, or zinc magnesium aspartate, is a popular supplement among athletes, bodybuilders, and fitness enthusiasts.

It contains a combination of three ingredients — zinc, magnesium, and vitamin B6.

ZMA manufacturers claim it boosts muscle growth and strength and improves endurance, recovery, and sleep quality.

This article reviews ZMA’s benefits, side effects, and dosage information.

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ZMA is a popular supplement that typically contains the following:

  • Zinc monomethionine: 30 mg — 270% of the Reference Daily Intake (RDI)
  • Magnesium aspartate: 450 mg — 110% of the RDI
  • Vitamin B6 (pyridoxine): 10–11 mg — 650% of the RDI

However, some manufacturers produce ZMA supplements with alternative forms of zinc and magnesium, or with other added vitamins or minerals.

These nutrients play several key roles in your body (1, 2, 3, 4):

  • Zinc. This trace mineral is necessary for more than 300 enzymes involved in metabolism, digestion, immunity, and other areas of your health.
  • Magnesium. This mineral supports hundreds of chemical reactions in your body, including energy creation and muscle and nerve function.
  • Vitamin B6. This water-soluble vitamin is needed for processes such as making neurotransmitters and nutrient metabolism.

Athletes, bodybuilders, and fitness enthusiasts often use ZMA.

Manufacturers claim that increasing your levels of these three nutrients can help increase testosterone levels, aid exercise recovery, improve sleep quality, and build muscle and strength.

However, the research behind ZMA in some of these areas is mixed and still emerging.

That said, consuming more zinc, magnesium, and vitamin B6 may provide many other benefits, such as improved immunity, blood sugar control, and mood. This especially applies if you’re deficient in one or more of the aforementioned nutrients (5, 6, 7).

Summary ZMA is a nutritional supplement that contains zinc monomethionine aspartate, magnesium aspartate, and vitamin B6. It’s typically taken to enhance athletic performance, improve sleep quality, or build muscle.

ZMA supplements are claimed to enhance athletic performance and build muscle.

In theory, ZMA may enhance these factors in those who are deficient in zinc or magnesium.

A deficiency in either of these minerals may reduce your production of testosterone, a hormone that affects muscle mass, as well as insulin-like growth factor (IGF-1), a hormone that affects cell growth and recovery (8).

In addition, many athletes may have low zinc and magnesium levels, which can compromise their performance. Lower zinc and magnesium levels may be the result of strict diets or losing more zinc and magnesium through sweat or urination (9, 10).

Currently, only a few studies have looked into whether ZMA can improve athletic performance.

One 8-week study in 27 football players showed taking a ZMA supplement daily significantly increased muscle strength, functional power, and testosterone and IGF-1 levels (11).

However, another 8-week study in 42 resistance-trained men found that taking a ZMA supplement daily did not raise testosterone or IGF-1 levels when compared to a placebo. Furthermore, it did not improve body composition or exercise performance (12).

What’s more, a study in 14 healthy men who exercised regularly showed that taking a ZMA supplement daily for 8 weeks did not raise total or free blood testosterone levels (13).

It’s worth noting that one of the authors of the study that found ZMA improved athletic performance has ownership in the company that produced the specific ZMA supplement. That same company also helped fund the study, so there may be a conflict of interest (11).

Individually, both zinc and magnesium have been shown to reduce muscle fatigue and either raise testosterone levels or prevent a fall in testosterone due to exercise, though it’s unclear if they’re more beneficial when used together (14, 15, 16).

All told, it’s unclear whether ZMA improves athletic performance. More research is needed.

Summary There is mixed evidence on ZMA’s effects on athletic performance. More human studies are needed in this area.

Studies on ZMA’s individual components suggest that the supplement may offer several benefits.

May boost immunity

Zinc, magnesium, and vitamin B6 play key roles in your immune health.

For example, zinc is essential for the development and function of many immune cells. In fact, supplementing with this mineral may reduce your risk of infections and aid wound healing (5, 17, 18).

Meanwhile, magnesium deficiency has been linked to chronic inflammation, which is a key driver of aging and chronic conditions like heart disease and cancer.

Conversely, taking magnesium supplements may reduce markers of inflammation, including C-reactive protein (CRP) and interleukin 6 (IL-6) (19, 20, 21).

Lastly, vitamin B6 deficiency has been linked to poor immunity. Your immune system requires vitamin B6 to produce bacteria-fighting white blood cells, and it enhances their ability to combat infection and inflammation (22, 23, 24).

May aid blood sugar control

Zinc and magnesium may help people with diabetes control their blood sugar levels.

An analysis of 25 studies in over 1,360 people with diabetes showed that taking a zinc supplement reduced fasting blood sugar, hemoglobin A1c (HbA1c), and post-meal blood sugar levels (6).

In fact, it found that supplementing with zinc lowered HbA1c — a marker for long-term blood sugar levels — to an extent similar to that of metformin, a popular diabetes drug (6, 25).

Magnesium may also improve blood sugar control in people with diabetes by improving the body’s ability to use insulin, a hormone that moves sugar from your blood into cells (26).

In fact, in an analysis of 18 studies, magnesium was more effective at reducing fasting blood sugar levels than a placebo in people with diabetes. It also significantly reduced blood sugar levels in those at risk of developing diabetes (27).

May help improve your sleep

The combination of zinc and magnesium may improve your sleep quality.

Research suggests that magnesium helps activate the parasympathetic nervous system, which is responsible for helping your body feel calm and relaxed (28, 29).

Meanwhile, supplementing with zinc has been linked to improved sleep quality in both human and animal studies (30, 31, 32).

An 8-week study in 43 older adults with insomnia showed that taking a combination of zinc, magnesium, and melatonin — a hormone that regulates sleep-wake cycles — daily helped people fall asleep faster and improved sleep quality, compared to a placebo (33).

May elevate your mood

Magnesium and vitamin B6, both of which are found in ZMA, may help elevate your mood.

One study in approximately 8,900 adults found that those under the age of 65 with the lowest magnesium intake had a 22% higher risk of developing depression (34).

Another 12-week study in 23 older adults showed that taking 450 mg of magnesium daily reduced depression symptoms as effectively as an antidepressant drug (7).

Several studies have linked low blood levels and intakes of vitamin B6 to depression. However, taking vitamin B6 doesn’t appear to prevent or treat this condition (35, 36, 37).

Summary ZMA may improve your immunity, mood, sleep quality, and blood sugar control, especially if you’re deficient in any of the nutrients it contains.

The vitamins and minerals in ZMA may play a role in weight loss.

In a 1-month study in 60 obese people, those taking 30 mg of zinc daily had higher zinc levels and lost significantly more body weight than those taking a placebo (38).

The researchers believed that zinc aided weight loss by suppressing appetite (38).

Other studies have found that obese people tend to have lower zinc levels (39).

Meanwhile, magnesium and vitamin B6 have been shown to reduce bloating and water retention in women with premenstrual syndrome (PMS) (40, 41).

However, no studies have found that ZMA can help you lose weight, especially body fat.

While ensuring you have enough magnesium, zinc, and vitamin B6 in your diet is important for your overall health, supplementing with these nutrients is not an effective solution for weight loss.

A better strategy for long-term weight loss success is to create a calorie deficit, exercise regularly, and eat plenty of whole foods such as fresh fruits and vegetables.

Summary Although its individual components are necessary for overall health, there is no evidence that ZMA can help you lose weight.

ZMA can be purchased online and in health food and supplement stores. It’s available in several forms, including capsule or powdered.

The typical dosage recommendations for the nutrients in ZMA are as follows:

  • Zinc monomethionine: 30 mg — 270% of the RDI
  • Magnesium aspartate: 450 mg — 110% of the RDI
  • Vitamin B6: 10–11 mg — 650% of the RDI

This is typically the equivalent to taking three ZMA capsules or three scoops of ZMA powder. However, most supplement labels advise women to take two capsules or two scoops of powder.

Avoid taking more than the recommended dose, as too much zinc may cause side effects.

Supplement labels often advise taking ZMA on an empty stomach about 30–60 minutes before bed. This prevents nutrients like zinc from interacting with others such as calcium.

Summary Supplement labels typically recommend three capsules or scoops of powder for men and two for women. Avoid consuming more ZMA than advised on the label.

Currently, no side effects have been reported related to supplementing with ZMA.

However, ZMA provides moderate-to-high doses of zinc, magnesium, and vitamin B6. When taken in high doses, these nutrients may have side effects, including (42, 43, 44, 45):

  • Zinc: nausea, vomiting, diarrhea, loss of appetite, stomach cramps, copper deficiency, headaches, dizziness, nutrient deficiencies, and reduced immune function
  • Magnesium: nausea, vomiting, diarrhea, and stomach cramps
  • Vitamin B6: nerve damage and pain or numbness in the hands or feet

Nevertheless, this shouldn’t be an issue if you don’t exceed the dose listed on the label.

Furthermore, both zinc and magnesium can interact with a variety of medications, such as antibiotics, diuretics (water pills), and blood pressure medicine (46, 47).

If you’re taking any medications or are pregnant or breastfeeding, speak with your healthcare provider before taking a ZMA supplement. Furthermore, avoid taking more ZMA than the recommended dose listed on the label.

Summary ZMA is generally safe when taken at the recommended dosage, but taking too much may cause side effects.

ZMA is a nutritional supplement that contains zinc, magnesium, and vitamin B6.

It may improve athletic performance, but current research shows mixed results.

Moreover, there is no evidence that ZMA can help you lose weight.

However, its individual nutrients may provide health benefits, such as improving blood sugar control, mood, immunity, and sleep quality.

This especially applies if you have a deficiency in one or more of the nutrients contained in ZMA supplements.