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Head-to-head evidence comparison — which supplement is right for you?
Vitamin B6 and Vitamin D3 are closely matched across evidence, studies, and safety.
Verdict
Likely helps
9 of 11 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
15 of 26 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Vitamin B6 and Vitamin D3 have evidence — compare verdict strength side-by-side.
25-100mg daily
Morning with food, Can take with other B vitamins
P-5-P (Pyridoxal-5-Phosphate)
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
2-4 weeks
1-2 cycles
Months of high doses
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Dosage exploration of combined B-vitamin supplementation in stroke prevention: a meta-analysis and systematic review
The American journal of clinical nutrition (2024) · Meta analysis · n=76664
In areas without and with partial folic acid fortification, combined B-vitamin supplementation significantly reduced the risk of stroke by 34% [RR: 0.66; 95% confidence interval (CI): 0.50, 0.86] and 11% (RR: 0.89; 95% CI: 0.79, 1.00), respectively.
Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life
The Cochrane database of systematic reviews (2018) · Meta analysis · n=83000
We found that giving B vitamin supplements to cognitively healthy adults, mainly in their 60s and 70s, probably has little or no effect on global cognitive function at any time point up to 5 years (SMD values from -0.03 to 0.06) and may also have no effect at 5-10 years (SMD -0.01).
Drug Efficacy in the Treatment of Antipsychotic-Induced Akathisia: A Systematic Review and Network Meta-Analysis
JAMA network open (2024) · Meta analysis · n=492
No association between effect sizes and psychotic severity was found.
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 systematic review of nutritional interventions for PMS psychological symptoms. Evidence quality limited by study heterogeneity and need for more consistent protocols.
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.
Both Vitamin B6 and Vitamin D3 are closely matched — the best choice depends on your specific health goals.
For support immune system, Vitamin D3 has a higher relevance score (92 vs 65).
No known interactions between Vitamin B6 and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.