Low-energy, depression, weight gain and thinning hair
With 123 million prescriptions in 2016, levothyroxine tops the charts as the most-prescribed drug. But a growing stack of research suggests this super-popular thyroid medication could also be one of the nation’s most over-prescribed pills—particularly for older adults and women with subclinical hypothyroidism, a slightly sluggish thyroid that may contribute to low energy, depression, weight gain and thinning hair.
Subclinical hypothyroidism is defined as a thyroid stimulating hormone (TSH) level of 4.6 to 10 mIU/L. A normal TSH level is 0.4 to 4.0 and full-blown hypothyroidism is 10 or higher. Researchers are finding that treating subclinical hypothyroidism— especially in people with no symptoms or without other indications that treatment may be a good idea (such as a high risk for heart disease)—isn’t helpful and could even be harmful. Yet prescriptions for this group are on the rise. In one 2014 study from the UK’s University of Cardiff, researchers found that 31% of people with mild hypothyroidism who got levothyroxine in the United Kingdom between 2001 and 2009 had no symptoms or other indications for a prescription.