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Head-to-head evidence comparison — which supplement is right for you?
Olive Leaf Extract 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
18 of 30 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Olive Leaf Extract and Vitamin D3 have evidence — compare verdict strength side-by-side.
500-1000mg (standardized to 15-20% oleuropein)
With meals
Standardized extract (15-20% oleuropein)
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
2-4 weeks
8 weeks
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
The impact of oleuropein, hydroxytyrosol, and tyrosol on cardiometabolic risk factors: a meta-analysis of randomized controlled trials
Critical reviews in food science and nutrition (2025) · Meta analysis · n=594
Fourteen human intervention studies with 594 participants were included.
Exploring the Benefits of Extra Virgin Olive Oil on Cardiovascular Health Enhancement and Disease Prevention: A Systematic Review
Nutrients (2025) · Systematic review
The beneficial effect was attributed to the polyphenols contained in EVOO.
Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials
Nutrition reviews (2024) · Meta analysis · n=703
In the meta-analysis, fasting glycemia, as evaluated in studies using a low dose of OLE, showed a significant result favoring the control group.
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 RCT showing 6.4 mmHg SBP reduction, but one crossover trial showed no effect. Mixed results suggest conservative effectiveness estimates. Primarily studied in hypertensive populations.
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 Olive Leaf Extract 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 75).
No known interactions between Olive Leaf Extract and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.