Does magnesium improve athletic performance?

Not for most people who train. A meta-analysis of 14 randomized trials found that magnesium supplements did not significantly improve peak torque, muscle strength or muscle power. Its authors concluded that the evidence does not support magnesium for muscle fitness in most athletes and active people, who tend to have relatively high magnesium status. People who are short of magnesium may be the exception, and that is where the few positive results come from.

Myth. A magnesium supplement does not make a well-fed athlete stronger or more powerful. This was tested in randomized trials, and the pooled result did not reach significance for any of the three measures of muscle performance.

The one recent trial in regular exercisers found the opposite of a boost, and the chart shows it.

What the trials found

Strength and power in people who train

The 14-trial meta-analysis found a difference in peak torque of 0.87 with a 95% interval from -1.43 to 3.18, a difference in muscle strength of 0.87 (-0.12 to 1.86), and a difference in muscle power of 3.28 (-14.94 to 21.50). Every interval crosses zero. The trials pooled athletes, untrained healthy people and older or alcoholic adults, with different tests in each, so the combined numbers are rough. An older systematic review of 12 human experiments, not all of them randomized, reached the same place: most evidence showed no effect on strength, anaerobic or aerobic performance.

The trial that went backwards

In a 2025 double-blind crossover trial, 15 healthy men and women aged 18 to 40 who exercised regularly took 300 mg of magnesium chloride twice a day or placebo for 9 days. Magnesium raised blood levels of ionized magnesium and lowered VO2max from 44.4 to 41.3 mL/kg/min. Mean power in a 30 second sprint fell from 439 to 415 W. Time over 10 km did not change, 1282 against 1281 seconds. The trial was small and short, and its dose, 600 mg a day, was well above the 350 mg upper limit for supplements. Its authors advise people who train and are not low in magnesium against taking it.

Where benefit appears

In 139 healthy women with a mean age of 71.5 attending a mild fitness program, 300 mg of magnesium oxide a day for 12 weeks improved a physical performance score by 0.41 points, chair stand time by 1.31 seconds and walking speed over 4 m by 0.14 m/s, compared with no treatment. There was no placebo, strength did not change, and the gains were larger in women eating less magnesium than the RDA. These were older women, not athletes.

Unsettled. A 2019 systematic review of minerals in sport found 22 magnesium studies with 663 people, ten of them randomized and only 72 of the participants women. It suggests that 300 to 500 mg a day for about one to four weeks may help jump height, one repetition maximum and fatigue resistance, with thigh strength gains after more than seven weeks. That review did not pool the numbers, its own wording is may, and its authors note that low doses may only be restoring normal levels. Most of that range also sits above the supplement upper limit.

A 2025 network meta-analysis of 80 trials in 1425 soccer players linked magnesium creatine chelate to higher mean power, with a standardized effect of 1.3. That product is a form of creatine, the effect is most likely the creatine, and the network gives no result for plain magnesium.

Are athletes short of magnesium?

A 2022 review of 31 studies found magnesium intake below the RDA in most studies of active people, even though they ate more magnesium than inactive controls. That is a comparison of diets, not a test of supplements, and the same review found no study that had measured how much magnesium athletes actually need.

Who should be careful

Not for everyone. The doses used in the trials on this page, 300 to 600 mg a day, run from just under to well above the upper limit the NIH sets for magnesium from supplements, 350 mg a day for adults. High doses can cause diarrhea, nausea and cramping, which is a poor trade before a race. The risk of magnesium toxicity rises with poor kidney function, because the kidneys can no longer clear the excess.

Magnesium may interact with oral bisphosphonates and with tetracycline and quinolone antibiotics, and the NIH notes that diuretics and proton pump inhibitors can change magnesium status. If you take any of these regularly, the timing of a magnesium supplement is a question for whoever prescribes them. The upper limit applies only to supplements. Magnesium from food is not capped.

What expert bodies say

The 2018 International Olympic Committee consensus on supplements for elite athletes names only caffeine, creatine, specific buffering agents and nitrate as having good evidence of benefit. Magnesium is not on that list. The European Union allows magnesium to be labeled as contributing to normal muscle function. That claim is about having enough magnesium, and it does not say that extra magnesium improves performance.

How we searched

What would change this answer

• A randomized trial in athletes selected for low magnesium status. Every positive signal points to people who are short, and the trials in athletes mostly did not measure status at all.
• A trial at doses within the 350 mg supplement limit, long enough to matter, in trained men and women. The 2019 review had only 72 women among 663 participants.
• A fresh meta-analysis. The last one pooled 14 trials up to July 2017 and mixed athletes with older and alcoholic adults.
• A study that measures how much magnesium athletes actually need. The 2022 review found none.

Sources

1. ev-mgath-01 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 14 RCTs, 542 participants
   The results of the meta-analysis suggested that no significant improvements in the supplementation group were observed regarding isokinetic peak torque extension [WMD = 0.87; 95% CI = (-1.43, 3.18)], muscle strength [WMD = 0.87; 95% CI = (-0.12, 1.86)] or muscle power [WMD = 3.28; 95% CI = (-14.94, 21.50)].
   
   Who: athletes or physically active individuals (215), untrained healthy individuals (95), elderly or alcoholics (232) in RCTs to July 2017
   Effect: peak torque WMD 0.87 (95% CI -1.43 to 3.18); muscle strength WMD 0.87 (-0.12 to 1.86); muscle power WMD 3.28 (-14.94 to 21.50), all non-significant
   Certainty: Fixed effects; heterogeneous populations and tests. The authors explain the absence of effect in athletes by high magnesium status.
   Magnes Res, 2017 · checked 2026-10-07 · we read the abstract
2. ev-mgath-02 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 14 RCTs
   Evidence does not support a beneficial effect of Mg supplementation on muscle fitness in most athletes and physically active individuals who have a relatively high Mg status.
   
   Who: athletes and physically active individuals with relatively high magnesium status
   Effect: no supportive evidence in athletes; possible benefit if magnesium deficient (elderly, alcoholics)
   Certainty: The authors' conclusion; magnesium status was not measured directly in most RCTs.
   Magnes Res, 2017 · checked 2026-10-07 · we read the abstract
3. ev-mgath-03 · Randomized controlled trial(s) · systematic review of experimental studies · n = 12 studies
   Most evidence indicates no effect of Mg supplementation on performance (strength, anaerobic-lactacid, and aerobic).
   
   Who: human experimental studies of magnesium supplementation and exercise performance, Medline 1966 to June 1999
   Effect: most evidence: no effect on strength, anaerobic-lactacid or aerobic performance; equivocal only for peak treadmill speed
   Certainty: Old review without quantitative pooling; not all studies were randomized, some with multivitamins.
   Clin J Sport Med, 2000 · checked 2026-10-07 · we read the abstract
4. ev-mgath-04 · Randomized controlled trial(s) · systematic review (PRISMA, PROSPERO CRD42018090502) · n = 22 articles, 663 participants (72 female), 10 RCTs
   Twenty two articles fulfilled the inclusion criteria for magnesium (Mg), including 663 participants (females, n = 72). These consisted of ten RCT’s, three of which referred to elite athletes.
   
   Who: exercising adults and athletes in studies of magnesium supplementation
   Effect: magnesium and iron the only minerals with articles rated 'strong'; effect depends on dose, baseline status, exercise intensity
   Certainty: No meta-analysis; "best evidence" among minerals does not mean an established effect. Only 72 women out of 663.
   Nutrients, 2019 · checked 2026-10-07 · we read the fulltext
5. ev-mgath-05 · Randomized controlled trial(s) · systematic review · n = 22 articles
   300–500 mg·day−1 of Magnesium in the short-term (~1–4 weeks) may have a positive influence on functional dynamic measures of muscle performance (CMJ, 1RM, fatigue resistance) and longer-term (>7 weeks) benefits on quadricep torque measurements.
   
   Who: exercising adults and athletes in studies of magnesium supplementation
   Effect: 300-500 mg/day short term (about 1-4 weeks): possible gains in CMJ, 1RM, fatigue resistance; over 7 weeks: quadriceps torque
   Certainty: Wording "may" from the key points; the authors write that low doses may only restore a normal level. 350-500 mg is above the UL for supplements (350 mg).
   Nutrients, 2019 · checked 2026-10-07 · we read the fulltext
6. ev-mgath-06 · Randomized controlled trial(s) · randomized double-blind placebo-controlled crossover trial · n = 15
   Compared with a placebo, MgCl2 supplementation increased the circulating ionized Mg concentration (p < 0.03), decreased the VO2max (44.4 ± 7.7 vs. 41.3 ± 8.0 mL/kg/min; p = 0.005), and decreased the mean power output during a 30 s sprint (439 ± 88 vs. 415 ± 88 W; p = 0.03).
   
   Who: healthy men and women aged 18-40 who were regular exercisers or competitive cyclists, MgCl2 300 mg twice daily or placebo for 9 days
   Effect: VO2max 44.4 vs 41.3 mL/kg/min (p = 0.005); 30 s sprint mean power 439 vs 415 W (p = 0.03); 10 km time trial 1282 vs 1281 s (p = 0.89)
   Certainty: Small sample, 9 days, dose 600 mg/day, roughly 1.7 times above the UL for supplements (350 mg). The authors advise those who train without hypomagnesemia not to take magnesium.
   Nutrients, 2025 · checked 2026-10-07 · we read the abstract
7. ev-mgath-07 · Randomized controlled trial(s) · randomized parallel-group controlled trial (no placebo) · n = 139 randomized, 124 analyzed
   After 12 wk, the treated group had a significantly better total SPPB score (Δ = 0.41 ± 0.24 points; P = 0.03), chair stand times (Δ = -1.31 ± 0.33 s; P < 0.0001), and 4-m walking speeds (Δ = 0.14 ± 0.03 m/s; P = 0.006) than did the control group.
   
   Who: healthy women, mean age 71.5 years, attending a mild fitness program; magnesium oxide 300 mg/day vs no intervention, 12 weeks
   Effect: SPPB +0.41 points (P = 0.03); chair stand -1.31 s (P < 0.0001); 4-m walking speed +0.14 m/s (P = 0.006); no effect on strength
   Certainty: Control without placebo; older women, not athletes. The effect is stronger when magnesium intake is below the RDA.
   Am J Clin Nutr, 2014 · checked 2026-10-07 · we read the abstract
8. ev-mgath-08 · Meta-analysis or systematic review · systematic review and Bayesian network meta-analysis of RCTs · n = 80 RCTs, 1425 players
   Magnesium creatine chelate (SMD: 1.3, large) and sodium pyruvate (SMD: 0.56, small) were associated with a significant effect on increasing mean power.
   
   Who: soccer players in RCTs of 31 dietary supplements or placebo, searched to 5 February 2024
   Effect: magnesium creatine chelate: mean power SMD 1.3 (large)
   Certainty: Very large SMDs from a small number of studies; the effect is most likely from creatine. The network does not give magnesium separately (without creatine).
   J Int Soc Sports Nutr, 2025 · checked 2026-10-07 · we read the abstract
9. ev-mgath-09 · Observational data · scoping review with meta-analysis of intake comparisons · n = 31 studies
   The Mg intake among physically active individuals was below the recommended dietary allowance in most studies.
   
   Who: professional or recreational athletes in studies to 31 May 2020
   Effect: intake below RDA in most studies; higher than controls in 5 pooled studies; no gold-standard studies of optimal intake
   Certainty: Comparison of intake (observational data), not the effect of supplements.
   J Nutr Sci Vitaminol (Tokyo), 2022 · checked 2026-10-07 · we read the abstract
10. ev-mgath-10 · Position of an expert body · consensus statement · n = —
    Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits.
    
    Who: high-performance athletes
    Effect: good evidence only for caffeine, creatine, buffering agents, nitrate
    Certainty: Magnesium in the consensus is considered as a way to correct deficiency, not as an ergogenic supplement (per the abstract, indirectly).
    Br J Sports Med, 2018 · checked 2026-10-07 · we read the abstract
11. ev-mgath-11 · Position of an expert body · entry in the EU Register on nutrition and health claims, authorized list · n = —
    POL-HC-6405 Magnesium Magnesium contributes to normal muscle function Authorised
    
    Who: EU food labeling
    Effect: claim POL-HC-6405 'Magnesium contributes to normal muscle function', status Authorised
    Certainty: An authorized functional claim does not mean that extra magnesium improves performance.
    EU Register on nutrition and health claims (European Commission), claim POL-HC-6405, snapshot 2026-09-21 · checked 2026-10-07 · we read the dataset
12. ev-mgath-12 · Position of an expert body · agency fact sheet · n = —
    The Tolerable Upper Intake Level for supplemental magnesium is 350 mg for adults, and it ranges from 65 to 350 mg for children and adolescents, depending on age. Too much magnesium from food does not pose a health risk in healthy individuals because the kidneys eliminate excess amounts in the urine [29]. However, high doses of magnesium from dietary supplements or medications often result in diarrhea that can be accompanied by nausea and abdominal cramping [1].
    
    Who: adults; children and adolescents 65 to 350 mg depending on age
    Effect: UL 350 mg/day supplemental magnesium (adults); food magnesium not limited
    Certainty: Doses in the RCTs of this page (300-600 mg/day) range from slightly below to well above this limit.
    NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals · checked 2026-10-07 · we read the section
13. ev-mgath-13 · Position of an expert body · agency fact sheet · n = —
    Magnesium may interact with certain medications, such as oral bisphosphonates, tetracyclines, and quinolone antibiotics. In addition, some medications, including diuretics and proton pump inhibitors, can affect magnesium status.
    
    Who: people taking these medications regularly
    Effect: interactions with bisphosphonates, tetracyclines, quinolones; diuretics and PPIs affect status
    Certainty: Practically: separate the timing of magnesium and these drugs; details in ODS.
    NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals · checked 2026-10-07 · we read the section
14. ev-mgath-14 · Position of an expert body · agency fact sheet · n = —
    The risk of magnesium toxicity increases with impaired renal function or kidney failure because the ability to remove excess magnesium is reduced or lost
    
    Who: people with impaired renal function or kidney failure
    Effect: higher risk of magnesium toxicity
    Certainty: General caveat without a numeric threshold.
    NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals · checked 2026-10-07 · we read the section