Hav you underwent thyroid test? if not you once better to undergo tests like hb levels, tsh, to exclude the reason. Evn less intake of food, noproper maintainence of quality food, less or non-nurtritious food, any vitamin deficiency, proteins, mal assimilation. Etc all may be the reason for thinning of hair.
Try to take homeo medicines weisbadan 200 twice/day for alternate days, lyco 1m weekly one dose, along with bioforce company's bio hair drops or r-89 drops daily in 1/4 th cup of luke warm water, twice/day fro 2-3 months n see the progress n let me know.
Take more proteinaceous food, like cereals, millets, sprouts, soya enriched food, milk, egg[if you r non. Vegetarian], fish, etc. More,
try to avoid taking junk, fast food, spicy, outside food, take more fruits, raw vegetables like carrots, keera etc. Whatever edible, take plenty of water, use shampoo, with herbal products, oil also, with arnica+jaborandi+cantahris mixed homeopathic oil will help for growth.