Why would someones hair thin or become loss?

most likely stressWhy would someones hair thin or become loss?
most likely dirty folicules (build up), if it is only loss it may be stress ...lack of vitamins or illness in the worst of the cases.Try changing shampoo for a milder one, If you use conditioner then use it ONLY on the tips, there麓s this shampoo Folicure its worked for me you can try it and try fermodyl treatments if you case is only cosmetic.