Product description For Hyaluronic Acid Serum, apply a few drops morning and evening to cleansed skin, followed by your favorite moisturizer. If irritation occurs, discontinue use and consult a doctor. It is recommended to test the patches before use. For the Niacinamide Serum, apply to the entire face morning and evening before thicker creams. Avoid eye contact. If irritation occurs, discontinue use and consult a doctor. It is recommended to test the patches before use. IMPORTANT: To optimize results, if you are using topical vitamin C, alternate application times with our Niacinamide serum. Apply vitamin C in the evening and our Niacinamide serum in the morning. Avertissement De Sûreté The Original Hyaluronic Acid