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ZMA, zinc, magnesium and B6

Also called: zinc monomethionine aspartate, magnesium aspartate, zinc magnesium B6, ZMA for sleep.

A patented combination of zinc, magnesium and B6 sold for testosterone and sleep, where the trials that followed do not find the effect.

Hormonal Sleep Recovery

What it is

ZMA combines about 30 mg of zinc (monomethionine and aspartate), 450 mg of magnesium (aspartate) and 10.5 to 11 mg of vitamin B6, a formula developed and first tested by its manufacturer. Zinc and magnesium are essential minerals whose deficiency has real effects. People buy it for testosterone, recovery and sleep.

What the label does not say

The original trial (2000) reported rises in testosterone, IGF-1 and strength in football players; Examine specifies that it was conducted by the manufacturer. Two later trials found nothing: 42 trained men for 8 weeks (no difference in total or free testosterone, IGF-1, strength or body composition) and 14 men for 56 days (serum zinc up, testosterone unchanged, in subjects whose zinc intake was already sufficient).
450 mg of magnesium exceeds the upper limit of 350 mg per day set for magnesium from supplements and medications, the one above which diarrhea becomes frequent. The label does not flag it.
30 mg of zinc represents nearly three times the recommended intake (11 mg for men) and 75% of the upper limit of 40 mg from all sources. The NIH reports that from 50 mg per day for weeks, zinc harms copper absorption, immunity and HDL; a multivitamin or lozenges add to the ZMA without the total showing up anywhere.
B6 at 10.5 mg is eight times the recommended intake of 1.3 mg; that is far from the 100 mg limit, but the NIH reports sensory neuropathies at doses below 500 mg in prolonged use. No trial found tests the sleep claim with the complete formula.

The forms on the shelf

Original formula: zinc 30 mg, magnesium 450 mg, B6 about 11 mg per day, as used in the 2004 trial.
"Zinc magnesium B6" copies: the same nutrients, variable salt forms; the NIH classes magnesium aspartate among the forms better absorbed than the oxide.
Zinc and magnesium taken separately: the same nutrients, adjustable doses.

Published reference values

Recommended intake: zinc 11 mg per day for men, 8 mg for women; magnesium 400 to 420 mg for men, 310 to 320 mg for women; B6 1.3 mg from 19 to 50.
Upper limits: zinc 40 mg per day from all sources; magnesium 350 mg per day from supplements and medications only; B6 100 mg per day.
Above that: diarrhea (magnesium), nausea and copper deficiency (zinc).

When

The trials gave it daily for 8 weeks. As with zinc on its own, spacing from certain antibiotics counts more than the hour.

Keep apart from

Quinolones and tetracyclines: at least 2 hours before or 4 to 6 hours after (zinc and magnesium).
Bisphosphonates: at least 2 hours apart (magnesium).
Copper: prolonged high-dose zinc reduces its absorption; not a matter of spacing but a cumulative total to watch.

To mention to a professional

Kidney failure (magnesium), prolonged intake above 40 mg of zinc from all sources, a multivitamin already containing zinc and magnesium, pregnancy and breastfeeding: check with a health care professional.

What it is sold for, and what the data show

ZMA is sold for testosterone, strength and sleep. Apart from the manufacturer's trial, two trials in men with normal zinc status showed no hormonal effect and none on strength, and no trial found covers sleep. Correcting a zinc or magnesium deficiency makes sense; doing it with a magnesium dose above the upper limit for supplements does not.

From the plate first

Zinc: oysters, beef, pumpkin seeds. Magnesium: pumpkin seeds, chia, almonds, spinach, according to the NIH fact sheets.

Sources

Educational information, drawn from the sources above. It does not replace the advice of a health professional, who remains the reference for your situation, your medications, pregnancy or breastfeeding.