How to stop & prevent hair loss? i did all types of tests out there & i am fine. yet, my hair keeps falling & it's frizzy with split ends. help plz!

Rogaine (minoxidil): If the complete work up of your hair loss, including blood tests for vit d, b, iron, thyroid, cell count, hormones, and biopsy were normal, then you can start rogaine (minoxidil). Rogaine (minoxidil) prevents cycling of hair follicles, keeping them in growth phase. It works by blocking the chemical signal which instructs hairs to fall out. You should see a difference in 6 mo, and should stay on it indefinitely.