Apply once a day, morning, or evening after cleansing. Apply 1/3 dropper with hands to a dry face.
If using in the morning, apply before a SkinCeuticals vitamin C antioxidant serum and a broad-spectrum sunscreen to protect the skin from UVA/UVB radiation.
In the evening, apply before serums and moisturizers.
Depending on the content of your usual regimen (retinoids, other acids), should you feel any discomfort, space out the application of Cell Cycle Catalyst or switch usage of Cell Cycle Catalyst to the morning or to the night to avoid over-application of active ingredients.
Gently smooth the serum onto dry skin. If using in the morning, apply before a SkinCeuticals vitamin C antioxidant serum and a broad-spectrum sunscreen to protect the skin from UVA/UVB radiation.