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Head-to-head evidence comparison — which supplement is right for you?
AREDS2 Formula vs Iodine: Iodine has the stronger overall evidence (8.5 vs 7/10); the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Iodine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mixed evidence
4 of 10 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both AREDS2 Formula and Iodine have evidence — compare verdict strength side-by-side.
One AREDS2 daily regimen, usually split into two servings: vitamin C 500 mg, vitamin E 400 IU, lutein 10 mg, zeaxanthin 2 mg, zinc 80 mg (as zinc oxide) and copper 2 mg (as cupric oxide)
with-meals
A product matching the AREDS2 composition exactly: vitamin C 500 mg, vitamin E 400 IU, lutein 10 mg, zeaxanthin 2 mg, zinc 80 mg, copper 2 mg
150-300mcg for maintenance; higher only if deficient under supervision
Any time with food
Potassium iodide (most common and studied)
Years — average follow-up was 6.3 years
Years
Long-term
Years
4-12 weeks
4-8 weeks
Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial.
JAMA (2013) · Rct · n=4203
Primary analysis was NULL: lutein/zeaxanthin HR 0.90 (98.7% CI 0.76-1.07, P=.12); DHA+EPA HR 0.97 (0.82-1.16, P=.70); both together HR 0.89 (0.75-1.06, P=.10)
A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.
Arch Ophthalmol (2001) · Rct · n=3640
Antioxidants plus zinc vs placebo for advanced AMD: OR 0.72 (99% CI 0.52-0.98). Zinc alone OR 0.75 (0.55-1.03); antioxidants alone OR 0.80 (0.59-1.09) — neither significant on its own
Long-term Outcomes of Adding Lutein/Zeaxanthin and ω-3 Fatty Acids to the AREDS Supplements on Age-Related Macular Degeneration Progression: AREDS2 Report 28.
JAMA Ophthalmol (2022) · Cohort · n=3882
10-year lung cancer odds ratio: 1.82 (95% CI 1.06-3.12, P=.02) for beta-carotene assignment vs 1.15 (0.79-1.66, P=.46) for lutein/zeaxanthin
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.
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.
AI-estimated from published studies. Interpret as directional guidance.
Iodine has a higher evidence score (8.5/10 vs 7/10) and wins in 2 of 3 categories.
No known interactions between AREDS2 Formula and Iodine have been documented in our database. However, always consult a healthcare provider before combining supplements.
Selenium helps; iodine can WORSEN Hashimoto’s. The honest take on "thyroid support".
What’s safe while nursing, the truth about milk-supply herbs, and what to avoid (it passes into milk).
Commonly recommended vs ask-your-clinician vs avoid — a general, safety-first overview.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.