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Head-to-head evidence comparison — which supplement is right for you?
Omega-3 wins 2 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
15 of 23 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)
2-3g combined EPA+DHA daily
With meals containing fat
Triglyceride form fish oil
4-12 weeks
4-8 weeks
4-8 weeks
2-4 weeks
Immediate
4-12 weeks
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.
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.
Omega-3 fatty acids for intermittent claudication
The Cochrane database of systematic reviews (2024) · Meta analysis · n=1830
Omega-3 compared with a control may have little to no effect on ankle-brachial index (MD -0.02, 95% CI -0.08 to 0.04; 3 studies, 168 participants; very low-certainty evidence).
A systematic review and meta-analysis of the omega-3 fatty acids effects on brain-derived neurotrophic factor (BDNF)
Nutritional neuroscience (2024) · Meta analysis · n=587
The present systematic review and meta-analysis indicate the efficacy of omega-3 FAs in increasing the serum concentration of BDNF.
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 EPA-dominant formulas >1g/day most effective. Effects plateau around 2-2.5g. Adjunctive use with antidepressants shows better outcomes than monotherapy.
AI-estimated from published studies. Interpret as directional guidance.
Omega-3 has a higher evidence score (9/10 vs 9/10) and wins in 2 of 3 categories.
For prenatal support, Omega-3 has a higher relevance score (88 vs 82).
No known interactions between Iodine and Omega-3 have been documented in our database. However, always consult a healthcare provider before combining supplements.