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What happens if you stop taking levothyroxine?

Medically reviewed by Sally Chao, MD. Last updated on Aug 22, 2023.

Official answer


As the main treatment for a sluggish thyroid, levothyroxine is meant to be taken for life. Stopping this medication may result in a return of symptoms such as:

  • Fatigue
  • Weight gain
  • Difficulty tolerating cold
  • Dry skin
  • Thinning hair.

This medication should not be discontinued without talking to your physician first.

Even changing to a version of the drug made by a different manufacturer can affect the amount of medicine that is absorbed and change your thyroid hormone levels.

For best results, levothyroxine should be taken consistently at the same dose from the same manufacturer at all times. Levothyroxine doses may need to be adjusted at other times, including pregnancy. Blood tests help guide dosage decisions.

Hypothyroidism occurs when your thyroid gland no longer produces adequate levels of thyroid hormone. Levothyroxine is the name of all man-made forms of the thyroid hormone T4. It is the main treatment for hypothyroidism or an underactive thyroid gland.

Brand names of levothyroxine include:

Your thyroid is a butterfly-shaped gland located in the neck. Its task is to produce hormones that are responsible for regulating many of your body's functions, including heart rate, breath, weight, digestion and moods.

Hypothyroidism can be caused by an autoimmune disease like Hashimoto’s thyroiditis, removal of the thyroid gland or radiation treatment to the area.


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