What is ZMA?

ZMA combines zinc, magnesium and vitamin B6. Exact mineral forms and amounts vary between products.

ZMA supplements are commonly taken before bed. Magnesium supports normal muscle and nerve function, zinc is required for protein synthesis and immunity, and vitamin B6 participates in amino-acid metabolism and neurotransmitter production.

Does ZMA improve sleep?

Direct evidence is limited. A 2024 trial found that ZMA taken during two nights of partial sleep restriction did not improve sleep or next-morning weightlifting performance.

Another 2024 trial in active men with adequate micronutrient intake found no meaningful improvement in sleep, repeated sprint performance or cognitive performance after an acute dose.

ZMA may be more relevant when it corrects low zinc or magnesium intake, but it is not an established treatment for insomnia.

Does ZMA increase testosterone?

An eight-week controlled trial involving resistance-trained men found no improvement in total or free testosterone, strength, body composition or training adaptations.

Products for testosterone support should not replace hormone testing or medical evaluation.

Dosage and safety

Check the total amounts obtained from ZMA, multivitamins and other mineral supplements.

European adult upper levels include approximately:

• zinc: 25 mg per day from all sources,
• supplemental magnesium: 250 mg per day,
• vitamin B6: 12 mg per day.

These are safety limits, not recommended supplement doses.

Excess magnesium can cause diarrhoea. Long-term high zinc intake can cause copper deficiency, while excessive vitamin B6 can result in peripheral neuropathy.

Conclusion

ZMA provides essential micronutrients but has not been shown to reliably increase testosterone, strength, muscle growth or sleep quality in people with adequate nutritional intake.

Its main potential value is correcting insufficient zinc or magnesium intake rather than acting as a direct hormonal or performance-enhancing supplement.

References

1. Wilborn CD et al. Effects of ZMA Supplementation on Training Adaptations and Markers of Anabolism and Catabolism. Published 2004.
2. Gallagher C et al. ZMA, Sleep Quality and Weightlifting Performance Following Partial Sleep Deprivation. Published January 17, 2024.
3. Edwards BJ et al. Effects of an Acute Dose of ZMA on Sleep and Next-Day Performance. Published 2024.
4. NIH Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. Updated January 6, 2026.
5. NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Updated January 6, 2026.
6. EFSA NDA Panel. Tolerable Upper Intake Level for Vitamin B6. Published May 17, 2023.