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Head-to-head evidence comparison — which supplement is right for you?
Magnesium wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
2 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
13 of 17 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Glycerol and Magnesium have evidence — compare verdict strength side-by-side.
1-1.5g per kg body weight
1-2.5 hours before endurance exercise, Consume with large volume of fluid (1-2L)
Glycerol powder (65% concentration typical)
200-350mg elemental magnesium daily
Evening for sleep/relaxation (glycinate), Morning for energy (malate), Anytime (citrate)
Depends on goal - see notes
During exercise (1-3 hours post-ingestion)
During exercise in heat
During exercise
1-2 hours post-ingestion
1-2 weeks
1-2 weeks
1 week
Immediate
Nutritional Ergogenic Aids in Combat Sports: A Systematic Review and Meta-Analysis
Nutrients (2022) · Meta analysis
In this regard, abilities including the number of attacks, reaction time, handgrip strength, power and TTE, among others, were improved.
The effect of pre-exercise oral hyperhydration on endurance exercise performance, heart rate, and thermoregulation: a meta-analytical review
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme (2024) · Meta analysis
Meta-analysis determined overall effect size (Hedges' g), and meta-regression the influence of independent moderators (ambient temperature, hyperhydration agent, exercise mode, extent of hyperhydration).
Meta-analysis: Effects of glycerol administration on plasma volume, haemoglobin, and haematocrit
Drug testing and analysis (2013) · Meta analysis
The meta-analysis revealed that the increase in plasma volume was 3.3% larger (95%-CI: 1.1-5.5%) after glycerol administration when compared to fluid only.
Magnesium supplementation in pregnancy
The Cochrane database of systematic reviews (2014) · Meta analysis · n=9090
Women receiving magnesium were significantly less likely to require hospitalisation during pregnancy (RR 0.65, 95% CI 0.48 to 0.86; three trials, 1158 women).Of the 10 trials included in the review, only two were judged to be of high quality overall.
Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis
Hypertension (2025) · Meta analysis · n=2709
38 RCTs with 2709 participants analyzed
Magnesium and Potassium Supplementation for Systolic Blood Pressure Reduction in the General Normotensive Population: A Systematic Review and Subgroup Meta-Analysis for Optimal Dosage and Treatment Length
Nutrients (2024) · Meta analysis
Both supplements demonstrated greater reductions in SBP for the general population at lower dosages and longer treatment durations.
Based on meta-analysis showing hyperhydration effects on endurance. Conservative effectiveness given limited direct glycerol performance studies in the provided evidence. GI side effects increase notably at higher doses.
Based on meta-analysis of 38 RCTs with 2709 participants showing -7.68 mmHg reduction in hypertensive individuals. Effects are greatest in those with hypomagnesemia. Limited evidence in normotensive populations.
AI-estimated from published studies. Interpret as directional guidance.
Magnesium has a higher evidence score (8.5/10 vs 5.8/10) and wins in 2 of 3 categories.
For speed up recovery, Magnesium has a higher relevance score (80 vs 55).
No known interactions between Glycerol and Magnesium have been documented in our database. However, always consult a healthcare provider before combining supplements.