In case you haven’t heard, your thyroid is kind of a big deal. The butterfly-shaped gland at the base of your neck takes iodine, found in many foods, and converts it into thyroid hormones. And that’s important because “every tissue and every cell is sensitive to TH,” says endocrinologist Antonio Bianco, MD, PhD, a professor of medicine at Rush University Medical Center in Chicago. TH impacts everything from metabolism to cognitive function to body temperature to energy levels. But for 1 in 8 women, this essential regulator goes on the fritz, producing too much—or too little TH, according to the American Thyroid Association.