Yes—a small share of people taking levothyroxine, a thyroid hormone medicine, still do not feel well. In a Mayo Clinic Press discussion, Dr. Juan P. Brito Campana explains this gap. He describes care for people with an underactive thyroid. For the Thyroid Hormone Replacement community, the key point is that treatment does not always bring full symptom relief. Levothyroxine supplies T4, one form of thyroid hormone. Cells turn T4 into T3, another form. Brito says learning about that process shifted treatment toward T4 alone. He describes it as the main treatment over the last two or three decades. Yet some people still do not feel better on levothyroxine alone. Brito says researchers are still trying to understand why. Sometimes, care teams try both T4 and T3 together. The excerpt does not show that using both works better. It gives no exact share of people with ongoing symptoms. It also gives no results comparing the two approaches. This is an expert discussion, not a study testing treatments. For members, this raises a useful tracking question: how do bloodwork and daily experience compare? A dated record can put test results beside notes about feeling better, worse, or unchanged. Recording the medicine used and when it changed adds context. That can make community comparisons more useful than a single result or a good day alone. Shared experiences can reveal questions worth exploring, without proving which treatment caused a change. What have you noticed when comparing your thyroid bloodwork with how you feel over time?