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Head-to-head evidence comparison — which supplement is right for you?
Vitamin D3 wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
6 of 7 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 Pregnenolone and Vitamin D3 have evidence — compare verdict strength side-by-side.
5-50mg daily
Morning (mimics natural production), With or without food
Micronized pregnenolone capsules
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
2-4 weeks
2-4 weeks
2-4 weeks
Variable
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Adjunctive use of anti-inflammatory drugs for schizophrenia: A meta-analytic investigation of randomized controlled trials
The Australian and New Zealand journal of psychiatry (2019) · Meta analysis · n=2914
The comparative evaluation of efficacy and safety supported the use of anti-inflammatory adjuvant therapy over the use of antipsychotics alone.
Sex hormones and oxytocin augmentation strategies in schizophrenia: A quantitative review
Schizophrenia research (2015) · Meta analysis · n=1149
Significant effects were found for estrogen action (k=10), regarding total symptoms (Hedges' g=0.63, p=0.001), positive (Hedges' g=0.42, p<0.001), and negative symptoms (Hedges' g=0.35, p=0.001).
Advancements in Non-Dopaminergic Treatments for Schizophrenia: A Systematic Review of Pipeline Developments
Pharmacopsychiatry (2024) · Systematic review
Systematic review examining Pregnenolone efficacy
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
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 8.5/10) and wins in 3 of 3 categories.
For fertility support, Vitamin D3 has a higher relevance score (85 vs 80).
No known interactions between Pregnenolone and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.