Thyroid hormones are produced by the thyroid gland, a butterfly-shaped gland in your neck. The main thyroid hormones are thyroxine (T4) and triiodothyronine (T3), which control your body’s metabolic rate.
What Thyroid Hormones Do:
These hormones regulate how quickly your body uses energy, makes proteins, and responds to other hormones. They affect heart rate, body temperature, digestion, muscle function, brain development, and bone maintenance. Essentially, thyroid hormones influence nearly every cell in your body.
TSH – The Regulator:
Thyroid-stimulating hormone (TSH) from the pituitary gland controls thyroid hormone production. When thyroid hormone levels are low, TSH rises to signal the thyroid to produce more. When levels are high, TSH drops. This is called a feedback loop.
Thyroid Imbalances:
Hypothyroidism (underactive thyroid) causes fatigue, weight gain, cold sensitivity, and slow metabolism. Hyperthyroidism (overactive thyroid) causes weight loss, rapid heartbeat, anxiety, and heat intolerance. Both require medical evaluation and treatment.

