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Head-to-head evidence comparison — which supplement is right for you?
Vitamin D3 wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
4 of 5 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
18 of 30 studies with measurable effects showed benefit.
Top outcomes
1-3g daily
Pre-workout for performance, Evening for sleep
Powder or capsules
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
4-8 weeks
8-12 weeks
2-4 weeks
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Effects of Nutritional Supplements on Endurance Performance and Subjective Perception in Athletes Exercising in the Heat: A Systematic Review and Network Meta-Analysis
Nutrients (2025) · Meta analysis · n=552
Standardized mean differences (SMDs) and posterior probabilities (P-scores based on Bayesian ranking) were calculated using random-effects and Bayesian models.
Effect of a 12-mo intervention with whey protein powder on cognitive function in older adults with mild cognitive impairment: a randomized controlled trial
The American journal of clinical nutrition (2025) · Rct · n=107
The results also found a significant beneficial effect of the active intervention for several secondary cognitive outcomes such as Digit Symbol Substitution Test score, and the mean difference between groups in the ITT analysis was 2.72 (95% CI: 0.20, 5.23).
Caffeine and taurine: a systematic review and network meta-analysis of their individual and combined effects on physical capacity, cognitive function, and physiological markers
Journal of the International Society of Sports Nutrition (2025) · Meta analysis
Posterior estimates indicated that CAF+TAU was associated with a credible positive effect on anaerobic capacity (g = 0.46, 95% CrI [0.19, 0.71]) and reaction time (g = 0.75, 95% CrI [0.29, 1.18]) compared to CAF or TAU alone.
Vitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and Omega-3 Trial
Nature communications (2025) · Meta analysis · n=5205
Mean body mass index (BMI) was 27.5 kg/m2 (SD = 5.3), with 51% female and 17% Black race/ethnicity.
Vitamin D Supplementation for Patients with Dysmenorrhoea: A Meta-Analysis with Trial Sequential Analysis of Randomised Controlled Trials
Nutrients (2024) · Meta analysis · n=687
TSA revealed that the current RCTs provide sufficient information.
Vitamin D and respiratory tract infections
BMJ (2017) · Meta analysis · n=11321
12% reduction in respiratory infections overall
Based on meta-analysis showing small-to-moderate effects (g=0.25). Conservative estimates due to high heterogeneity (I²=61%) and mixed study quality. Effects primarily seen in anaerobic capacity and reaction time when combined with caffeine.
Meta-analysis showed 12% overall reduction in respiratory infections, with greater benefits in severely deficient individuals. Daily dosing more effective than bolus. Conservative estimate assumes most users not severely deficient.
AI-estimated from published studies. Interpret as directional guidance.
Vitamin D3 has a higher evidence score (7.5/10 vs 7.5/10) and wins in 1 of 3 categories.
For bone health, Vitamin D3 has a higher relevance score (92 vs 80).
No known interactions between Taurine and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.