Medically reviewed by Kelly Wood, MD Key Takeaways High TSH levels usually mean the thyroid is underactive, which is called hypothyroidism.  TSH levels can change due to factors like age, sex, and ...

Seasonal variation in one of the hormones used to monitor thyroid function could in turn lead to false diagnoses of subclinical hypothyroidism and unnecessary prescriptions of levothyroxine, says Yale ...

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 ...

When assessing thyroid function, thyroid hormone levels ― particularly free thyroxine (FT4) levels ― consistently show stronger associations with a wide array of clinical conditions than the standard ...

Metformin, a commonly used drug for treating type 2 diabetes, is linked to an increased risk of low thyroid-stimulating hormone levels in patients with underactive thyroids, according to a study. Low ...