If you are already using a topical hair loss formulation with Finasteride or Dutasteride, you can still use Strut Hair Booster. You will simply choose one time a day to apply Strut Hair Booster (many people choose the same time as their other formula for ease of application). Then, you will apply to the scalp in a thin layer directly after you have spread out the Finasteride or Dutasteride formulation. If you prefer to wait a few minutes in between to allow the first formulation to absorb, or you do want to space out the application entirely, that is also fine.