Hello, Welcome to Healthcare Magic. I have read your question fully and understand your concerns. Thyroid disorders fall manly into two categories: Underproduction of Thyroid hormones called Hypothyroidism. The symptoms of this are weight gain, low mood, constipation, hair loss, intolerance to cold, dry skin, slow movements etc. Another category is over production of thyroid hormones called Hyperthyroidism and the symptoms are; palpitations, diarrhoea, weight loss, sweating, intolerance to heat, anxiety etc. From what you have told in your query, you may be having hypothyroidism. You could get yourself tested for it. You could get a Thyroid profile done; it is a blood test which measures TSH and T4, T3 levels. Hair fall could also be due to general aging process. Low Testosterone again is a consequence of aging, as the person becomes older, his testosterone production falls. I hope this answer has helped you. Thank you Regards Dr Sunita Sayammagaru