TG and thyrotoxicosis: Importantly, HT can manifest as euthyroidism (normal thyroid function), hypothyroidism (characterized by insufficient thyroid hormone production leading to symptoms such as fatigue, weight gain, and cold intolerance), or thyrotoxicosis (characterized by excess thyroid hormone leading to symptoms such as tachycardia, weight loss, and increased sweating) due to destructive thyroiditis (also known as Hashitoxicosis).