How long does the hair loss treatment take?

I am considering a hair loss treatment. How long does the procedure take?
Lately, the amount of hair falling out every time I wash my hair is different from before, so even though I lack time as a working professional, I am seriously looking into hair loss treatments such as scalp mesotherapy or injection therapy.
I am curious about the approximate actual time spent sitting in the chair receiving the treatment, excluding the time spent registering and waiting, when visiting a clinic for hair loss treatment on a weekday or during a busy week.
I would like to know the detailed duration of the hair loss treatment so that I can easily coordinate my schedule. I think it would be helpful to know in advance whether the procedure is short enough to be completed during spare time like a lunch break or after work, or if it takes quite a long time as it includes thorough scalp care.