I know many people with hair loss that use ketoconazole 2% shampoo times a week, thinking it fights seb derm. Others use salycylic acid shampoos 4 – 5 times a week thinking it thickens the hair shaft
My question is: Could overusing active medicated shampoos for long periods, contrary to official recommendations lead to permanent hair loss?
I don’t think shampoos will cause permanent hair loss per se, but you should not be using medications of any sort in ways they are not prescribed or recommended.
Ketoconazole shampoo (also known as Nizoral, among other names) does work in treating seborrhoeic dermatitis, but you should follow your doctor’s recommendation for dosing.