The thyroid gland regulates your body weight and metabolism.

Many people gain weight after thyroid removal surgery. However, some people may lose weight or not experience any weight changes.

Research from 2023 did not identify specific factors that contributed to either weight gain or weight loss in people who had a thyroidectomy. Some factors that did not correlate with weight loss or gain among the participants included:

  • age
  • sex
  • thyroid function before surgery
  • thyroid status after surgery
  • thyroid pathology (genetic testing of the removed thyroid gland)

How thyroid removal affects your thyroid function can depend on whether your thyroid removal surgery was complete or partial, and the reason for removal. If you still have some of your thyroid gland, you may not notice significant changes to your weight following surgery.

But if you had your thyroid removed due to hyperthyroidism (an overactive thyroid), you will likely have hypothyroidism (an underactive thyroid). Hypothyroidism typically slows many of your body’s functions, including your metabolism. This can potentially contribute to weight changes.

However, if you’ve had your thyroid removed, you will need to take thyroid medication. You may experience weight changes until your doctor finds the right dose of medication.

Having your thyroid removed means that you will take thyroid replacement medication to help manage the functions that your thyroid gland used to perform.

This medication can help manage body functions like your metabolism.

Too little or too much thyroid replacement medication may affect your body’s functions in a way similar to hypothyroidism or hyperthyroidism.

With hypothyroidism, this may look like fatigue, weight gain, and constipation.

With hyperthyroidism, this may include a rapid heartbeat, weight loss, and frequent bowel movements.

If you’re experiencing symptoms of either condition, it’s best to talk with a doctor and revisit your medication.

If you’re experiencing weight gain or weight loss after a thyroidectomy, it’s best to talk with your doctor. They may need to adjust your medication.

If you notice weight gain, you can take some steps to manage your weight by:

If you’re experiencing weight loss, it’s best to talk with a doctor. They may recommend changes to your diet and medication.