As a monotherapy, Pigmentbio C-Concentrate is used as a cure of 1 month up to 3 months. STEP 1 For the first use, press firmly with both thumbs on the pack’s cap until the canister is fully engaged to release vitamin C. Unscrew the white cap and check that all the vitamin C powder has been released. Screw on the dropper and shake for 10 seconds to mix the vitamin C. STEP 2 Apply 5 drops every evening to face and neck after cleansing with Pigmentbio H2O or Pigmentbio Foaming Cream. Can be applied on its own or before Pigmentbio Night Renewer in the evening. STEP 3 To maintain good results all year long, renew the 1 month cure every 3 months. Avoid the eye contour area. Follow the instructions for use. Tingling sensations related to the mechanism of action may be felt, they should rapidly disappear. If irritation persists, stop using the product and consult a healthcare professional.