I'm using minoxidil 5% to treat my hair fall. Should I shampoo my head daily, or once every two days?

You can shampoo your hair as many times as you would like. It does not affect genetic balding. If you feel shampooing makes your hair / scalp dry, then shampoo less.

Thinning Hair -- Rogaine, Propecia, Viviscal, Progesterone, PRPIf you have thinning hair you really need an evaluation to see if it is genetic or from another cause like stress or autoimmune. If it is determined to be genetic there are many options and traditional treatments like rogaine foam and propecia pills can be used. I have great success in my practice using injectable progesterone and prp to the scalp. Postmenopausal women also benefit from spironolactone. I suggest seeing a dermatologist with expertise in hair loss. Best, Dr. Emer.

In general, washing your hair is not going to cause hair loss.  If the hair is shedding for other reasons, shampooing may highlight this effect.  In conclusion, washing your hair nightly or every other night would not in my opinion have any effect on your hair loss progress.  Consulting with a hair loss expert if you haven't done that yet would be a good idea.