Will long-term use of Euthyrox cause weight gain?
Jul 09, 2025
Source: Cainiu Health
Dr. Yang Chuanjia
Introduction
Long-term administration with an appropriate dose maintains stable thyroid hormone levels within the normal range, keeps the body's metabolism balanced, coordinates energy expenditure and intake, and prevents abnormal weight gain due to medication, thereby allowing long-term weight stability consistent with the weight fluctuation patterns observed in healthy individuals. Long-term administration of an insufficient dose fails to correct hypothyroidism, and persistent hormone deficiency will result in a consistently low metabolic rate.
Levothyroxine sodium tablets (Euthyrox) will not cause weight gain when taken long-term at the appropriate dose with normal thyroid function. However, weight gain may occur if the dose is insufficient, leading to persistent hypothyroidism. If any abnormalities occur, timely medical attention is recommended. Detailed explanation is as follows:
When the appropriate long-term dose is taken and thyroid hormone levels remain steadily within the normal range, the body's metabolism remains balanced, with coordinated energy expenditure and intake. Body weight will not exhibit abnormal increases and can remain stable long-term, consistent with the weight fluctuation patterns seen in healthy individuals.
If the dose taken long-term is insufficient and hypothyroidism remains uncorrected, prolonged hormone deficiency will keep metabolic rates consistently low, reducing calorie consumption. Excess energy gradually converts to stored fat, resulting in weight gain and an increasingly obese body shape. This may also be accompanied by symptoms such as fatigue and cold intolerance.
Regular monitoring of thyroid function is necessary when taking levothyroxine sodium tablets long-term. Dose adjustments must strictly follow medical advice, while maintaining a balanced diet and moderate exercise to prevent abnormal weight changes.
