Reducing the frequency of minoxidil application from twice daily to once daily may result in a slightly reduced efficacy of the medication. Minoxidil is typically recommended for twice-daily use to maintain consistent levels of the active ingredient in the scalp. By using it less frequently, you may experience a slight decrease in its overall effectiveness, potentially leading to a slower rate of hair regrowth or maintenance.
However, it's important to note that the impact of reducing the dosage may vary among individuals. Factors such as the stage of hair loss, individual response to treatment, and genetics can influence the extent of the effect. Some individuals may find that using minoxidil once daily still yields satisfactory results, while others may experience a more noticeable decline in efficacy.