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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
11 of 14 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
15 of 26 studies with measurable effects showed benefit.
Top outcomes
100-200mg daily
Morning with food, Can be divided into two doses
Pycnogenol (standardized extract)
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
4-8 weeks
6-12 weeks
4-8 weeks
Initial use
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Phlebotonics for venous insufficiency
The Cochrane database of systematic reviews (2020) · Meta analysis · n=7690
Pooled data suggest that phlebotonics probably increase adverse events slightly, compared to placebo (RR 1.14, 95% CI 1.02 to 1.27; 37 studies; 5789 participants; moderate-certainty evidence).
Pine bark (Pinus spp.) extract for treating chronic disorders
The Cochrane database of systematic reviews (2020) · Meta analysis · n=1641
In a mixed group of participants with type 1 and type 2 DM we do not know whether pine bark extract decreases HbA1c (MD -0.20 %, 95% CI -1.83 to 1.43; one study; 67 participants; very low-certainty evidence).
Effect of pycnogenol supplementation on blood pressure: A systematic review and meta-analysis of clinical trials
Phytotherapy research : PTR (2020) · Meta analysis · n=922
Pooled analysis suggested that pycnogenol supplementation can reduced systolic blood pressure (SBP) of (-3.22 mmHg; 95% CI [-5.52, -0.92]) and diastolic blood pressure (DBP; -1.91 mmHg; 95% CI [-3.64, -0.18]).
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-analyses showing modest reductions in systolic (-3.22 mmHg) and diastolic (-1.91 mmHg) blood pressure. Effects are clinically small and studies show heterogeneity.
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 (9/10 vs 9/10) and wins in 1 of 3 categories.
For reduce inflammation, Pine Bark Extract has a higher relevance score (75 vs 58).
No known interactions between Pine Bark Extract and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.