Hi, Welcome and thanks for posting your query to HCM. After reading your query it appears that your brittle hair problem is due to thyroid problem. It is quite common to find this kind of problem if there is any hormonal imbalance is present. In your self it is super-added by the medicines also. The important thing is to not to get panicky about the situation. It is a common problem where the hormones are not normal. Now it can be related to both T3 and T4 as both are important in working of normal processes of body. To get improved you hormonal level should be in normal level. So talk to your docotr for the same. you can follow the suggestions as below:Other than that you can improve your diet at the best. Eat at least 3-4 fruits per day. Every fruit is good but you can make a combination of sour with sweet fruits such as oranges, papaya and other of seasonal fruits. Pulses are good source of proteins. So everyday have a bowel full of mixed pulses. Add green leafy vegetables additionally in the pulses which contains lot of iron and vitamins in it. Sprouts are the best source of fibers, minerals vitamins and proteins too. so add it at-least alternate day if you can not make in everyday s part of meal. Reduce your stress f any kind as stress also leads to falling and weakness of hair. Hope this information helps you. If you have any further queries I will be happy to help. Wish you good health Dr Sanjay Kumar Kanodia MD (Dermatology)