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Head-to-head evidence comparison — which supplement is right for you?
Iodine and Vitex are closely matched across evidence, studies, and safety.
Verdict
Mixed evidence
4 of 12 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
12 of 13 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Iodine and Vitex have evidence — compare verdict strength side-by-side.
150-300mcg for maintenance; higher only if deficient under supervision
Any time with food
Potassium iodide (most common and studied)
20-40mg extract (standardized to 0.5% agnuside)
Morning, Consistently at same time daily
Standardized extract (0.5% agnuside or 0.6% aucubin)
4-12 weeks
4-8 weeks
1-3 cycles
2-3 cycles
1-2 cycles
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.
Vitex agnus-castus in premenstrual syndrome: A meta-analysis of double-blind randomised controlled trials
Complementary Therapies in Medicine (2019) · Meta analysis · n=1878
Vitex significantly reduced overall PMS symptom scores vs placebo
Herbal medicine for depression and anxiety: A systematic review with assessment of potential psycho-oncologic relevance
Phytotherapy research : PTR (2018) · Systematic review
Overall, 45% of studies reported positive findings with fewer adverse effects compared with conventional medications.
A Critical Approach to Evaluating Clinical Efficacy, Adverse Events and Drug Interactions of Herbal Remedies
Phytotherapy research : PTR (2016) · Review
A critical evaluation of the clinical data regarding the adverse effects has shown that herbal remedies are generally better tolerated than synthetic medications.
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 meta-analysis of RCTs showing large effect size. Most effective for irritability, mood swings, and breast tenderness. Standardized extracts (Ze 440, BNO 1095) had strongest evidence. High heterogeneity noted between studies.
AI-estimated from published studies. Interpret as directional guidance.
Both Iodine and Vitex are closely matched — the best choice depends on your specific health goals.
For testosterone & cortisol balance, Vitex has a higher relevance score (92 vs 85).
No known interactions between Iodine and Vitex have been documented in our database. However, always consult a healthcare provider before combining supplements.