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Head-to-head evidence comparison — which supplement is right for you?
Copper vs Iodine: they're closely matched on evidence (5.5 vs 8.5/10); they're alternatives for boost daily energy — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Copper and Iodine are closely matched across evidence, studies, and safety.
Verdict
Likely helps
10 of 11 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mixed evidence
4 of 11 studies with measurable effects showed benefit.
Top outcomes
1-2mg daily (typically to balance zinc)
With food to reduce GI upset, Separate from zinc by 2+ hours if taking both
Copper Bisglycinate (gentle, well-absorbed)
150-300mcg for maintenance; higher only if deficient under supervision
Any time with food
Potassium iodide (most common and studied)
Ongoing
4-8 weeks
With chronic excess
4-12 weeks
4-8 weeks
Micronutrient deficiencies in patients with celiac disease: A systematic review and meta-analysis
International journal of immunopathology and pharmacology (2025) · Meta analysis · n=4140
Meta-analysis revealed a significant difference in hemoglobin levels between patients with CeD and controls (standardized mean difference (SMD) -0.59 (95% confidence interval (CI) -0.8459 to -0.3382); P = 0.0003).
Trace Elements and Risk of Immune-Mediated Skin Disease: A Systematic Review and Meta-analysis
Nutrition reviews (2025) · Meta analysis · n=7014
Serum trace element levels showed more significant changes in patients with IMSDs than in healthy controls.
Healthy lifestyle choices: new insights into vitiligo management
Frontiers in immunology (2024) · Meta analysis · n=8542
Vitamin C [mean difference (MD), -0.342; 95% confidence interval (CI), -1.090-0.407; p >0.05), folic acid (MD, -1.463; 95% CI, -7.133-4.208; p >0.05), and selenium (MD, 0.350; 95% CI, -0.687-1.387; p >0.05) levels did not differ between the groups.
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.
Both Copper and Iodine are closely matched — the best choice depends on your specific health goals.
For boost daily energy, Iodine has a higher relevance score (95 vs 50).
No known interactions between Copper and Iodine have been documented in our database. However, always consult a healthcare provider before combining supplements.
AREDS2 works for diagnosed AMD; lutein/screen-strain claims are weaker. Who actually benefits.
When to take what, with or without food, and which supplements compete vs pair well.
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).
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.