Im losing my hairs and im 21 years old. i have dandruff in my hairs. please tell me what can i do to prevent hair loss.?

Good hair care: There are many simple steps to take if you are losing your hair. Hopefully, it is only because of your family genetics. Try, over the counter Minoxidil (rogaine) 2 x each day, take biotin (a vitamin part of vit b complex) 5000 units each day, wash with a mild shampoo and use conditioner, do not brush your hair or use chemicals or hot heat. Blow drying is ok with low or cool settings.

Hair issues: Thinning hair or hair falling out can be caused by several conditions, including but not limited to thyroid disorders, stress, or scalp infections to name a few. Since you have dandruff, there may be an underlying scalp infection, so best to see a dr. For an evaluation and treatment. Good luck to you.