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Head-to-head evidence comparison — which supplement is right for you?
Taurine vs Vitamin D3: Vitamin D3 has the stronger overall evidence (7.5 vs 7.5/10); they're alternatives for bone health — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Vitamin D3 wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Too few graded studies
2 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
7 of 14 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
and 1 more not shown
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) · Rct · n=22220
Ancillary analysis of VITAL: 22,220 adults without T2D randomized to vitamin D3 2000 IU/day or placebo, with a meta-analysis of 3 additional trials.
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
25 RCTs, 11 321 participants aged 0 to 95 years. Vitamin D reduced acute respiratory tract infection overall (adjusted OR 0.88, 95% CI 0.81 to 0.96).
Rests on two meta-analyses that state the dose range they cover. One (PMID 29546641, 10 studies, single doses or up to 2 weeks of 1 to 6 g a day) found endurance improved (Hedges' g 0.40) and that the dose did not change the size of the effect. The other (PMID 40852891, 23 randomised trials of a single dose, 308 participants) found a small-to-moderate overall gain (g 0.25, I² 61%), no significant dose-response within 1 to 6 g, and rated the certainty low to very low. So the curve is flat from 1 g to 6 g. No minimum, optimal or ceiling dose is set, because neither abstract reports an effect or safety at a single dose within the range.
Both points come from a meta-analysis of double-blind cholecalciferol trials in people aged 60 and over (PMID 15886381). Trials at 700 to 800 IU a day cut hip fracture risk by 26% (RR 0.74) and non-vertebral fractures by 23%, plotted at 800 IU. Trials at 400 IU a day showed no benefit (hip fracture RR 1.15), and the WHI trial of 400 IU with 1,000 mg calcium did not significantly reduce hip fracture (PMID 16481635). Most of these trials also gave calcium, and the Cochrane review found vitamin D alone unlikely to prevent fractures while vitamin D with calcium gave a small reduction (PMID 24729336). Doses above 800 IU were not compared, so no optimal dose or ceiling is set.
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 documented interaction was found in the data searched. This does not establish that this exact combination is safe.
Caffeine, citrulline, beta-alanine, creatine — the ingredients that work, at clinical doses (vs fairy dusting).
The honest tier list — proven staples vs situational vs mostly marketing. The hub the other guides feed into.
On Ozempic/Wegovy/Mounjaro? What actually helps — muscle preservation, GI relief, nutrient gaps (no upsell).
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The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.