Inadequate doses of Eugenol will show symptoms of hypothyroidism, such as coldness, chills, constipation, and weakness, etc. Because some thyroid hormone has been supplemented, more severe hypothyroid symptoms, such as swelling, hair loss, and severe anemia, will not occur. Eugenol is a synthetic thyroxine, also called levothyroxine sodium, which is usually given to patients with hypothyroidism as a replacement therapy for thyroid hormones. In the early stages of thyroid hormone replacement therapy, patients usually experience this condition, also known as hypothyroidism. Patients with hypothyroidism should visit the hospital regularly for thyroid function tests while taking Eugenol, and communicate with their endocrinologist for appropriate dose adjustments of thyroid hormone, gradually finding the right dose for them and maintaining their treatment.