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Head-to-head evidence comparison — which supplement is right for you?
Black Seed Oil wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
11 of 12 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mixed evidence
4 of 12 studies with measurable effects showed benefit.
Top outcomes
1-3g oil (or 200-400mg thymoquinone)
With meals
Cold-pressed oil softgels
150-300mcg for maintenance; higher only if deficient under supervision
Any time with food
Potassium iodide (most common and studied)
4-8 weeks
4-8 weeks
8-12 weeks
4-12 weeks
4-8 weeks
Does Nigella sativa supplementation improve cardiovascular disease risk factors? A comprehensive GRADE-assessed systematic review and dose-response meta-analysis of 82 randomized controlled trials
Pharmacological research (2025) · Meta analysis · n=5026
Our findings suggest that N. sativa could be a promising adjunct therapy for improving cardiovascular disease (CVD) risk factors.
A systematic review on anti-diabetic plant essential oil compounds: Dietary sources, effects, molecular mechanisms, and safety
Critical reviews in food science and nutrition (2024) · Systematic review
They can also significantly inhibit the generation of TBARS and MDA, reduce oxidative stress, increase insulin levels, adiponectin, and glycoprotein enzymes, boost antioxidant enzymes like SOD, CAT, and GPx, as well as reduce glutathione and vital glycolytic enzymes.
Effect of Nigella sativa Intake on Oxidative Stress and Inflammation in Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-analysis of Randomized Controlled Trials
Current pharmaceutical biotechnology (2024) · Meta analysis · n=1033
In addition, SOD: (SMD: 1.35; (95% CI, from 0.77 to 1.93); P = 0.00) and TAC (SMD: 2.82; (95% CI, from 0.55 to 5.084); P = 0.01) levels significantly increased in the intervention group compared to the placebo group.
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-analysis of 1086 participants showing significant reductions in CRP and TNF-α, but no effect on IL-6. High heterogeneity between studies limits confidence.
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.
Black Seed Oil has a higher evidence score (6.5/10 vs 8.5/10) and wins in 2 of 3 categories.
For fertility support, Black Seed Oil has a higher relevance score (80 vs 70).
No known interactions between Black Seed Oil and Iodine have been documented in our database. However, always consult a healthcare provider before combining supplements.