There are 2 important benefits to using minoxidil once per day. The first being you don't have to use it at an inopportune time, such as in the morning before styling your hair, the second being reduced costs.
The issue with a once a day protocol is that it goes against the directions on the box. The directions for men state that the product should be used twice per day. However the duration of effect for minoxidil is 21 hours, which nearly covers the entire day. Is this enough to get good results? Dr. Russell Knudsen, one of the 5 original dermatologists involved in minoxidil trials in 1984 suggests it is. You can see his discussion of once per day application here.
If you are more comfortable using the product twice per day, as instructed then feel free to do so, but note that a once per day protocol is likely to achieve the same results. As always ensure that your applications get good coverage of the affected areas and that your scalp is as clean as possible before applying.
If you have questions, feel free to get in touch with us.