Methods A randomized clinical trial to placebo (P) or MTF use. Previous fine needle aspiration confirming the diagnosis is necessary to inclusion. Patients will receive similar tablets of MTF and placebo and instruct to take 3 tablets/day of MTF (500mg/tablet). Thyroid volume, as TN volume, will be assess by ultrasound, both in the beginning, six months and one year after randomization, by the same researcher blinded regarding location group. Blood samples to measure: TSH, FT4, TPO-Ab, lipid profile, glucose and insulin were done after 8h fasting.