Low TSH levels are generally associated with hyperthyroidism and can lead to various symptoms. General complaints that may be observed with this condition include rapid fatigue, a feeling of weakness, depression, unhappiness, edema in the hands and feet, hoarseness, decreased appetite, and constipation. Additionally, symptoms frequently encountered in hyperthyroidism due to low TSH may include: Rapid heartbeat, anxiety and tension, unexplained weight loss, frequent urination, visual disturbances, sweating and reduced heat tolerance, thin, warm, and moist skin, enlargement of the thyroid gland (goiter), irregular menstrual periods, irritability, muscle weakness, and hair loss.