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Head-to-head evidence comparison — which supplement is right for you?
Vitamin A wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Probably helps
8 of 15 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mixed evidence
8 of 17 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Niacin and Vitamin A have evidence — compare verdict strength side-by-side.
500-2000mg daily for lipid effects; 50-500mg for general health
With food (reduces flush), Evening for lipid effects, Split doses for high amounts
Immediate-release niacin (nicotinic acid)
2500-5000 IU daily (retinol); up to 25000 IU (beta-carotene)
With fat-containing meal, Any time of day
Mixed carotenoids or low-dose retinyl palmitate
4-8 weeks
4-8 weeks
30-60 minutes after dose
2-4 weeks
2-4 weeks
4-8 weeks
With chronic excess
Niacin for primary and secondary prevention of cardiovascular events
The Cochrane database of systematic reviews (2017) · Meta analysis · n=39195
Participants randomised to niacin were more likely to discontinue treatment due to side effects than participants randomised to control group (RR 2.17, 95% CI 1.70 to 2.77; participants = 33,539; studies = 17; I2 = 77%; moderate-quality evidence).
Effect of lipid-lowering therapies on lipoprotein(a) levels: a comprehensive meta-analysis of randomized controlled trials
Atherosclerosis (2025) · Meta analysis · n=145314
Among available LLTs, PCSK9mAbs, inclisiran, CETPi, and niacin significantly decreased Lp(a) levels.
A terminal metabolite of niacin promotes vascular inflammation and contributes to cardiovascular disease risk
Nature medicine (2024) · Meta analysis
Lastly, treatment with physiological levels of 4PY, but not its structural isomer 2PY, induced expression of VCAM-1 and leukocyte adherence to vascular endothelium in mice.
Effects of primary or secondary prevention with vitamin A supplementation on clinically important outcomes: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis
BMJ open (2024) · Meta analysis · n=672
Vitamin A did not reduce mortality in individually randomised trials (RR 0.99, 95% CI 0.93 to 1.05; I²=32%; p=0.19; 105 trials; moderate certainty), and this effect was not affected by the risk of bias.
Vitamin and Mineral Supplementation During Pregnancy on Maternal, Birth, Child Health and Development Outcomes in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis
Nutrients (2020) · Meta analysis · n=451723
IFA supplementation showed notable improvement in maternal anemia and the reduction in low birthweight, whereas LNS supplementation had no apparent effect on outcomes; further research that compares LNS and MMN supplementation could help understand differences with these commodities.
Vitamin A supplements for reducing mother-to-child HIV transmission
The Cochrane database of systematic reviews (2017) · Meta analysis · n=6601
Antepartum or postpartum vitamin A supplementation, or both, probably has little or no effect on mother-to-child transmission of HIV in women living with HIV infection and not on antiretroviral drugs.
Based on multiple meta-analyses showing HDL increases. Higher doses increase discontinuation rates due to side effects (RR 2.17). Immediate-release forms have better lipid effects but more flushing.
AI-estimated from published studies. Interpret as directional guidance.
Vitamin A has a higher evidence score (9/10 vs 9/10) and wins in 1 of 3 categories.
For healthy aging, Vitamin A has a higher relevance score (80 vs 65).
No known interactions between Niacin and Vitamin A have been documented in our database. However, always consult a healthcare provider before combining supplements.