Hello, You are feeling tiredness and weakness. You also have brittle hair. You have been on prescription medicine Synthyroid as you have history of having thyroid. You have not mentioned the last report of T3,T4, TSH. Brittle hair and tiredness are symptoms of thyroid dysfunction. You should talk to your treating doctor if you think the doses being given to you are not okay. However, to help your hair get better you should take care of your diet. When your diet is poor, it will be reflected in your body and in your hair. Healthy diet for hair means taking a lot of lean protein and fresh fruits and vegetables. Take diet rich in nutrients like biotin, vitamin E, vitamin C and iron. Wash your hair alternately with a mild herbal shampoo and keep it hydrated and conditioned. You can apply natural oil (coconut oil, almond oil, etc.). Avoid exposing your hair on bright sunlight. Avoid the use of sprays and harsh chemical based hair styling products. Be gentle while combing your hair especially when wet. Prefer to use wide toothed comb on wet hair. You have lost weight, so you may be feeling tired. No worries, make sure that you are getting adequate quality sleep at night. Avoid smoking, taking alcohol and addictions if any. If diabetic, control blood glucose level at all cost. To get rid of tiredness, take green tea, pumpkin seeds, bananas, oat meal, yogurt, walnut, water melon, beans, spinach, iron, etc. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician