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Head-to-head evidence comparison — which supplement is right for you?
Milk Thistle 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
9 of 13 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)
200-400mg silymarin (standardized extract)
With meals, Split into 2-3 doses
Standardized extract (70-80% silymarin)
4-12 weeks
4-8 weeks
4-8 weeks
8-12 weeks
4 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.
Clinical Efficacy of Curcumin, Resveratrol, Silymarin, and Berberine on Cardio-Metabolic Risk Factors Among Patients With Type 2 Diabetes Mellitus: A Systemic Review and Bayesian Network Meta-Analysis
Phytotherapy research : PTR (2025) · Meta analysis · n=1337
For HbA1c, silymarin was more effective than resveratrol (MD -2.08, 95%Cl -3.50 to -0.72) (P < 0.05).
Effects of different natural products in patients with non-alcoholic fatty liver disease-A network meta-analysis of randomized controlled trials
Phytotherapy research : PTR (2024) · Meta analysis · n=2509
The results of the network meta-analysis showed that artichoke leaf extract confers a relative advantage in reducing the aspartate aminotransferase (AST) levels (SUCRA: 99.1%), alanine aminotransferase (ALT) levels (SUCRA: 88.2%) and low-density lipoprotein cholesterol (LDL-C) levels (SUCRA: 88.9%).
Are alterations needed in Silybum marianum (Silymarin) administration practices? A novel outlook and meta-analysis on randomized trials targeting liver injury
BMC complementary medicine and therapies (2025) · Meta analysis · n=3545
According to the findings of this meta-analysis silymarin administration showed a significant reduction in AST (SMD [95% CI]: - 0.670 [- 0.931, - 0.408], p-value = 0.000), and ALT (SMD [95% CI]: - 0.912 [- 1.177, - 0.646], p-value = 0.000) levels.
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 significant ALT/AST reduction. Effect size modest (SMD -0.67 to -0.9). Effectiveness assumes standardized 80% silymarin extract. Lower bioavailability forms may require higher doses.
AI-estimated from published studies. Interpret as directional guidance.
Milk Thistle has a higher evidence score (9/10 vs 9/10) and wins in 2 of 3 categories.
No known interactions between Iodine and Milk Thistle have been documented in our database. However, always consult a healthcare provider before combining supplements.