What does it mean if my TSH is low but T3 and T4 are normal?

If your TSH is low but T3 and T4 are within the normal range, it could indicate subclinical hyperthyroidism, where the thyroid is slightly overactive but has not yet caused a significant change in hormone levels. This condition may be caused by Graves’ disease, thyroid nodules, or overmedication with thyroid hormone replacement. Although symptoms may be mild or absent, subclinical hyperthyroidism can increase the risk of osteoporosis and heart problems over time. Your doctor may recommend regular monitoring or treatment depending on the severity of your symptoms and risk factors.