- Reformulated with a 400% increase of the active ingredient from 0.5% to 2.5% - An innovative complex that both reduces hair loss and stimulates your hair follicles to get healthier and more vibrant hair.* - Helps to stimulate hair follicles and affects the cells in both the growth phase and the resting phase to help dormant hair follicles to return to the growth phase so that the hair has the opportunity to start growing as usualSwiss Clinic Hair Serum 2.5% *Please note- This product has recently been reformulated and improved with a 400% increase of the active ingredient (0.5% to 2.5%) Hair Serum 2.5% is a cosmetic treatment with an innovative complex that both reduces hair loss and stimulates your hair follicles to get healthier and more vibrant hair.* Thanks to the cell-communicating ingredients, the hair serum helps to stimulate the hair follicles and affects the cells in both the growth phase and the resting phase to help dormant hair follicles to return to the growth phase