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Anatomy

Thyroid gland

A butterfly-shaped gland in the neck that produces hormones controlling metabolism.

The thyroid is a small, butterfly-shaped gland at the front of your neck, just below the Adam's apple. It is made up of two lobes - one on each side of the windpipe - joined by a narrow strip of tissue called the isthmus.

Its main job is to produce thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3). These hormones circulate in the bloodstream and help govern how fast almost every cell in the body works - a process called metabolism.

The thyroid's output is regulated by the pituitary gland at the base of the brain, which releases thyroid-stimulating hormone (TSH) to signal how much hormone is needed. When levels are high, TSH falls; when they drop, TSH rises.

Because thyroid hormones influence so many systems - heart rate, temperature, mood, weight, digestion, and more - conditions affecting the thyroid can produce a very wide range of symptoms.

Common questions

Where exactly is the thyroid?
It sits at the front of the lower neck, wrapping around the trachea (windpipe) just below the larynx (voice box). A healthy thyroid is usually not palpable.
What does the thyroid do in everyday terms?
It makes T4 and T3 hormones that act like the body's accelerator - influencing heart rate, body temperature, energy levels, weight, mood, and digestion.
Can the thyroid be felt from outside?
A normal thyroid is not usually palpable. If it becomes enlarged (a goitre), it may be visible as a swelling in the front of the neck and detectable on examination by a doctor.

Related terms

Thyroid lobe Isthmus TSH (thyroid-stimulating hormone) Free T4 (free thyroxine) Free T3 (free triiodothyronine)

ThyroidTools is an independent, patient-led project - not a charity, not a medical service, and not affiliated with any healthcare organisation or clinical body. We're not your doctor. We're the friend who helps you get more from seeing one. Nothing here is medical advice; always speak to a qualified clinician about your own situation.