Does Hypothyroidism Cause Weight Gain?

Yes, hypothyroidism commonly causes weight gain due to a significantly slowed metabolism. When your thyroid gland produces insufficient hormones, your metabolic rate can drop by 15-40%, making your body burn fewer calories at rest. This metabolic slowdown often leads to gradual weight gain of 5-10 pounds, even without changes in diet or exercise habits. The weight gain typically includes both fat accumulation and fluid retention from reduced kidney function. Studies show that 60-80% of people with untreated hypothyroidism experience some degree of weight gain. Proper thyroid hormone replacement therapy can help restore normal metabolism and make weight management easier.