Magnesium, zinc and omega-3: limited evidence and what is not shown
Magnesium
The Heffernan et al. review (2019) includes 22 studies on magnesium, with 663 participants. It says evidence is growing that magnesium may matter for muscle mass, power and inflammation, but that the effects of supplementing remain ambiguous. Inconsistencies may depend on dose, baseline mineral status, exercise intensity and population.1 On cramps, the Garrison et al. Cochrane review (2020) includes 11 trials and 735 people. For idiopathic cramps, largely in adults with a mean age between 61.6 and 69.3 years and nocturnal cramps, differences from placebo are small and not significant (for example -0.18 cramps per week at four weeks, confidence interval -0.84 to 0.49, moderate certainty). For pregnancy cramps the literature is conflicting. The authors found no randomised trials of magnesium for exercise-associated cramps.2 So it is not evidence on exercise cramps, nor proof that it helps nobody.
Zinc and other minerals
In the same review zinc counts 9 experiments. The authors conclude that for most minerals and trace elements there is little evidence supporting supplementation to improve performance, with the possible exception of iron (in particular biological situations) and magnesium, which currently have the best-quality evidence. Some may have potential, but better studies are needed.1 The AIS lists zinc in Group A, for identified athletes with protocols, not for general use.4 Iron, calcium and vitamin D are in the vitamins and minerals guide.
Omega-3
A 2022 systematic review of 15 randomised trials (461 healthy people) concludes that omega-3 fatty acids do not improve hypertrophy, strength or muscle markers of inflammation and damage beyond the benefits of training itself. They do improve recovery from delayed-onset muscle soreness and some measures of muscle function (range of motion, electromechanical delay, muscle quality). Only six studies measured hypertrophy.3 This source does not cover endurance performance, so we say nothing here on that point.
Limits and safety
- Reviews of small studies that differ in doses and populations: results cannot be added together and do not hold for everyone.
- The sources are not about safety: with medicines or medical conditions, even without a risk documented here, see a doctor, as for any supplement.
- Anti-doping and contamination: the WADA list changes every year and an unchecked product can contain banned substances.65 WOLF LAB does not certify products or batches and does not recommend brands.
How we reviewed it
Document review: 2019 systematic review on minerals, 2020 Cochrane on magnesium and cramps, 2022 review on omega-3 (abstract), AIS, IOC and WADA pages. Primary studies not read. No WOLF LAB tests.
Limits. Small studies that differ in doses and populations. Cochrane on non-exercise cramps. Omega-3 and endurance not covered. Zinc only in the minerals review. No dose. Not medical advice.
Sources
- Heffernan SM et al. The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review. Nutrients, 2019. PMC.
- Garrison SR et al. Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews, 2020. PubMed.
- López-Seoane J et al. N-3 PUFA as an ergogenic supplement modulating muscle hypertrophy and strength: a systematic review. Critical Reviews in Food Science and Nutrition, 2022. PubMed.
- AIS (Australian Sports Commission). Sports supplements, Group A. AIS.
- Maughan RJ et al. IOC consensus statement: dietary supplements and the high-performance athlete. British Journal of Sports Medicine, 2018. PMC.
- WADA. The Prohibited List. WADA.
Sources read on 31 October 2026: abstracts and, for minerals, the magnesium section; not every full text or primary study. General information, not medical advice. No WOLF LAB tests.