The thyroid gland uses iodine to produce thyroxine (T4) and triiodothyronine (T3), the hormones that regulate metabolic rate, body temperature, energy production, neurological function, and cardiovascular activity. Without adequate iodine: 1️⃣ TSH may rise as the pituitary attempts to stimulate thyroid output 2️⃣ T4 and T3 production can become impaired 3️⃣ Metabolic efficiency and cellular energy production may decline Both deficiency and excess iodine can disrupt thyroid physiology, which is w