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Head-to-head evidence comparison — which supplement is right for you?
Green Tea Extract vs Vitamin D3: they're closely matched on evidence (7.5 vs 7.5/10); they're alternatives for reduce inflammation — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Green Tea Extract and Vitamin D3 are closely matched across evidence, studies, and safety.
Verdict
Likely helps
8 of 10 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
18 of 30 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Green Tea Extract and Vitamin D3 have evidence — compare verdict strength side-by-side.
250-500mg EGCG (or 500-1000mg green tea extract)
With meals, Morning or pre-exercise
Standardized extract (45-50% EGCG)
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
Acute and 4-8 weeks
Acute
30-60 minutes
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Green tea (Camellia sinensis) for the prevention of cancer
The Cochrane database of systematic reviews (2020) · Meta analysis · n=1795
For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence).
Impact of flavan-3-ols on blood pressure and endothelial function in diverse populations: a systematic review and meta-analysis of randomized controlled trials
European journal of preventive cardiology (2025) · Meta analysis · n=5205
Flavan-3-ol interventions included epicatechin, epigallocatechin-gallate, cocoa products, tea, grape extract, and apples delivering 586 mg (95% CI 510, 662) total flavan-3-ols.
The effects of green tea extract supplementation on body composition, obesity-related hormones and oxidative stress markers: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials
The British journal of nutrition (2024) · Meta analysis · n=3802
Pooled effect sizes indicated that BM, BFP, BMI and MDA significantly reduced following GTE supplementation.
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 9.29 mg/dl LDL reduction with 107-856 mg/d EGCG. Optimal cardiovascular benefits observed at 400-500 mg/day. Take with food to reduce GI side effects.
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 Green Tea Extract and Vitamin D3 are closely matched — the best choice depends on your specific health goals.
For reduce inflammation, Green Tea Extract has a higher relevance score (85 vs 58).
No known interactions between Green Tea Extract and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.
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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.