Hormones produced by the thyroid gland that regulate metabolism, energy, body temperature, and growth.
FULL EXPLANATION
The thyroid gland produces two main hormones: T4 (thyroxine) and T3 (triiodothyronine). T4 is the storage form, converted to the active T3 in tissues. TSH (thyroid-stimulating hormone) from the pituitary controls thyroid function.
Thyroid hormones affect virtually every cell in the body, regulating metabolic rate, heart rate, body temperature, mood, and energy levels. Both hypothyroidism (underactive) and hyperthyroidism (overactive) have significant health consequences.
WHY IT MATTERS
Thyroid function is fundamental to metabolism and energy. Subclinical thyroid dysfunction is common and can affect weight, energy, mood, and cognitive function.
HOW TO IMPROVE
Support thyroid health through adequate iodine, selenium, and zinc; managing stress; avoiding excessive goitrogens; and maintaining healthy body weight.
NORMAL RANGES
TSH: 0.4-4.0 mIU/L (optimal often 1-2). Free T4: 0.8-1.8 ng/dL. Free T3: 2.3-4.2 pg/mL. Optimal ranges may be narrower than \"normal\" ranges.
RELATED TERMS
Metabolic Rate
The rate at which your body burns calories at rest to maintain basic life functions.
Insulin
A hormone produced by the pancreas that regulates blood sugar by promoting glucose uptake into cells.
Cortisol
The primary stress hormone that regulates metabolism, immune response, and the body's fight-or-flight response.
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