Hyperthyroidism (overactive thyroid) doesn’t usually cause weight gain, though it may cause other weight changes. Sometimes, treatment for hyperthyroidism can lead to weight gain. Hyperthyroidism ...

Subclinical hyperthyroidism means that a person has low or undetectable levels of thyroid-stimulating hormone (TSH) with normal levels of free thyroid hormones. It usually does not cause symptoms. The ...