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Head-to-head evidence comparison — which supplement is right for you?
Niacin wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mixed evidence
4 of 11 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
8 of 15 studies with measurable effects showed benefit.
Top outcomes
150-300mcg for maintenance; higher only if deficient under supervision
Any time with food
Potassium iodide (most common and studied)
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)
4-12 weeks
4-8 weeks
4-8 weeks
4-8 weeks
30-60 minutes after dose
Maternal Iodine Status and Birth Outcomes: A Systematic Literature Review and Meta-Analysis
Nutrients (2023) · Meta analysis · n=42269
Birth weight was similar between UIC ≥ 150 μg/L and <150 μg/L (difference = 30 g, 95% CI −22 to 83, p = 0.3, n = 13, I2 = 89%) with no evidence of linear trend (4 g per 50 μg/L, −3 to 10, p = 0.2, n = 12, I2 = 80%).
Iodine fortification of foods and condiments, other than salt, for preventing iodine deficiency disorders
The Cochrane database of systematic reviews (2019) · Meta analysis · n=4317
This is equivalent to an increase of 38.32 µg/L (95% CI 24.03 to 52.61 µg/L).
Systematic review and meta-analysis of iodine nutrition in modern vegan and vegetarian diets
The British journal of nutrition (2023) · Meta analysis · n=4421
Vegan diets had the poorest iodine intake (17·3 µg/d) and were strongly associated with lower iodine intake (P = < 0·001) compared with omnivorous diets.
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.
Based on meta-analyses showing urinary iodine concentration increases with supplementation. Effects only meaningful in iodine-deficient populations. Excessive intake (>300mcg) may increase thyroid cancer risk. Most studies used potassium iodide; kelp-derived forms have variable bioavailability.
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.
Niacin has a higher evidence score (9/10 vs 9/10) and wins in 1 of 3 categories.
No known interactions between Iodine and Niacin have been documented in our database. However, always consult a healthcare provider before combining supplements.