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Does Cytomel help with weight loss?

Medically reviewed by Carmen Fookes, BPharm. Last updated on Aug 23, 2021.

Official answer


Although Cytomel does help with weight loss in people prescribed it for hypothyroidism (low thyroid levels), it is not effective at usual dosages at reducing weight in people with normal thyroid levels. Using high dosages of Cytomel to reduce weight in people with normal thyroid levels is dangerous, not safe, and can be life-threatening. Strokes, seizures, shock, coma and death have been reported in people who have taken higher than recommended dosages of Cytomel. Some symptoms of Cytomel toxicity (overdose), such as confusion, disorientation, or heart changes may not appear until several days after ingestion. Cytomel should not be used as a treatment for weight loss or obesity.

Cytomel has a narrow therapeutic index – this means there is a fine line between taking too much or having too little. Over or under treatment can be detrimental to a young person’s growth and development, cardiovascular function, bone metabolism, reproductive health, emotional state, gastrointestinal function, and glucose and lipid metabolism. In people taking Cytomel for low thyroid levels, the dosage must be carefully titrated to avoid these effects, and possible drug or food interactions taken into account.

Cytomel contains liothyronine in sodium salt form (also called LT3) which is a man-made form of a naturally occurring hormone produced by our thyroid glands called liothyronine. Cytomel may be used to increase levels of thyroid hormone in the body and treat thyroid deficiency disorders (hypothyroidism). It may also be given to help manage thyroid cancer in addition to surgery and radiotherapy, or to help diagnose conditions such as mild hyperthyroidism (high thyroid levels).

  • Cytomel. Updated 06/2021. Pfizer Laboratories Div Pfizer Inc

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