Hello, Welcome to Healthcaremagic and i am Dr Talal hussain. Well overactive thyroid or Hyperthyroidism is very common condition. And it does cause weight lose also .But what needs to be considered that hyperthyroid causes all system to over work especially heart. Which could result into palpitations, loose motion, feeling hot all the time etc. You might be in the initial stage of hyperthyroidism that is why you might be not effected with other problems i mentioned , but it might start any moment. You might start having increased blood pressure also which will put undue pressure on the heart and weaken you heart. Therefore it is better that you start with medication and avoid complication of overactive thyroid . i hope this answer was helpful. If you need any further assistance feel free to contact us in writing . Regards . Dr Talal hussain