"Medical privacy rules forbid Brown from naming all the athletes he has treated for that condition. But among those who have publicly acknowledged being treated for thyroid problems by Brown or unnamed other physicians are American runners Ryan Hall, Galen Rupp, Amy Yoder Begley, Bob Kennedy and Patrick Smyth. "I knew hypothyroidism was kind of like something that was being diagnosed more among elite runners," said Smyth, a marathoner who in 2011 started feeling chronically tired. When a physician near his California home found no evidence of thyroid dysfunction, Smyth flew to Houston to see Brown, who conducted some blood tests and diagnosed him with the condition. Smyth, now retired, said the medication never enhanced his performance.?