Weight Gain

Underactive Thyroid Gland Can Cause Weight Gain.

What is thyroid gland?

The thyroid gland, which is a major endocrine gland in our body, is in the front part of the neck. It secretes triiodothyronine (T3) and Thyroxine (T4) hormones. Production of thyroid hormones is regulated by a hormone known as Thyroid stimulating hormone (TSH), which is secreted by the pituitary gland in the brain. Dietary iodine is an essential nutrient for thyroid hormone production.

Effects of thyroid hormones

Thyroid hormones:

  • Increase heart rate and pumping action of the heart.
  • Help maintain the normal breathing cycle.
  • Increase bowel movements.
  • Promote red blood cells to release oxygen to the tissues.
  • Increase speed of muscle activity.
  • Promote liver gluconeogenesis, glucose absorption in the intestine, and help increase the blood-glucose level.
  • Increase breakdown of lipids in the fat tissues.
  • Basically, thyroid hormones regulate growth and metabolism, including energy consumption in the body.

Underactivity of the thyroid gland (hypothyroidism)

The thyroid gland fails to produce enough thyroid hormones in hypothyroidism. Underactivity of the thyroid gland reduces your heart rate and pumping action of the heart. It reduces liver gluconeogenesis, bowel movements and absorption of glucose, resulting in low energy level in the body. Hypothyroidism reduces speed of muscle activity and release of oxygen to tissues by red cells.

Therefore, hypothyroidism causes low basal metabolic rate and lower energy consumption in your body. Consequently, excess dietary calories will be deposited as fat in adipose tissues. Hypothyroidism slows the breakdown of lipids in the fat tissues and makes you fatter.

Symptoms of hypothyroidism

  • Weight gain
  • Tiredness
  • Loss of appetite
  • Sensitivity to cold weather (cold intolerance)
  • Poor memory
  • Depression
  • Lump in the neck (enlarged thyroid gland/goitre)
  • Poor libido
  • Excessive sleep during the day
  • Swollen eyes
  • Joint pain (arthralgia)
  • Muscle pain (myalgia)
  • Dry, rough skin
  • Dry and brittle hair
  • Loss of eyebrows
  • Constipation
  • Heavy periods (menorrhagia) or infrequent periods (oligomenorrhoea)
  • Muscle weakness and stiffness
  • Some psychiatric conditions
  • Deafness
  • Coma (a state of unconsciousness)

If you have any symptoms of underactivity of the thyroid gland, consult your doctor. The doctor may offer you some blood tests (TSH, free T4, Free T3, and thyroid antibodies), which help diagnose hypothyroidism. This clinical condition can be managed easily.


(Photo courtesy: Tony Alter)

About the author
Dr. Nalaka Priyantha is the founder and author of 'DRN Health'. He currently works at the Ministry of Health, Sri Lanka as a senior medical officer. He is blogging about healthy living since 2012.
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