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.

You did not state your
sex, something that has great value when answering this type of question. I
always start off with the drug finasteride for one year in men. Many men under 30, will stop or reverse the thinning that
occurs with genetic balding with the drug finasteride. I also always perform
bulk measurements with an instrument called HAIR CHECK which is a good way to
determine just how much thinning you have that you can not see. Once this test
is done and you have gone a year, I often repeat the test as it gives an
excellent measurement on what happened to your hair over the year. If it got
better and some of the thinning reversed, maybe you won't need a transplant and
that is the goal that you should look to do. Of course, a good doctor is
critical to this course.If you are a woman, then you absolutely need a doctor to make the diagnosis and treating your hair loss with minoxidil without a diagnosis will probably get you no where.