Hi, From the information you have provided, your weight gain is most likely caused by your thyroid problem. Is it well controlled with thyroid hormone supplements? If this is not the case, then please go on and get this well addressed by your physician. Can you also report your weight and height to us? I recommend using drugs for weight loss only in extremes or persons who present with excess weight related complications. I hope this addresses your query fully. If need be, feel free to contact us again.