Iodine

Essential for thyroid health with strong evidence for deficiency correction. Supplementation is unnecessary and potentially harmful in iodine-replete populations.

A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.

Iodine is a core component of T3 and T4 thyroid hormones. WHO estimates 2 billion people are at risk of iodine deficiency globally. Salt iodization has dramatically reduced deficiency-related disorders. Excess iodine can paradoxically cause hypothyroidism or hyperthyroidism, particularly in those with underlying thyroid disease.

• Essential for thyroid hormone synthesis
• Critical during pregnancy for fetal brain development
• Corrects deficiency-related cognitive and metabolic impairment

RDA: 150 mcg for adults, 220-290 mcg during pregnancy/lactation. Supplementation beyond RDA is rarely needed in iodine-sufficient regions.

• Thyroid dysfunction at excessive doses
• Metallic taste
• GI irritation
• Acne-like skin eruptions

Excess iodine can cause or worsen thyroid dysfunction. Those with Hashimoto's thyroiditis may be particularly sensitive. Do not exceed UL of 1100 mcg/day.

Most people in developed countries get adequate iodine from iodized salt and dairy. Supplementation is primarily indicated for documented deficiency, pregnancy, or restricted diets.

• Energy45
• Longevity40