Levothyroxine is actually a synthetic hormone, which is used for the treatment of hypothyroidism. In conditions of hypothyroidism, the thyroid gland does not produce enough thyroid hormone, resulting in symptoms like weight gain, hair loss, poor growth, slow speech, dry thick skin and lack of energy. When taken in prescribed doses levothyroxine is known to correct these symptoms. Additionally levothyroxine is also used for the treatment of goiter and hypothyroidism.

One can find extensive information on levothyroxine over the internet. You can also shop around for levothyroxine at online pharmacies. It is always recommended though that you consult your physician or pharmacist before you take this medication.
 
The dose may differ from patient to patient based on conditions such as the presence of cardiovascular disease and blood levels of thyroid hormone. Usually effects one to three weeks after this medication are taken.

You should always inform your doctor about any other medical condition that you may be having before taking levothyroxine. For instance patients with diabetes may require an increase or decrease in the dose of insulin if they are taking levothyroxine. Levothyroxine is also known to interfere with the working of other medicines such as warfarin which is a blood thinner. In such conditions constant monitoring of blood clotting is required. Side effects of levothyroxine include increased heart rate, heat intolerance, nervousness, insomnia, vomiting, weight loss and fever. Levothyroxine is also known to cause irregular menstrual cycles in women. In case of any other persistent or serious side effect, one should immediately seek medical attention.