Clinique Smart Night Clinical Md Treatment Retinol Serum is a skin-repairing night treatment that jumpstarts the anti-aging process with retinol plus hydration. What you should know about retinol: * Retinol is an extremely effective and powerful anti-aging ingredient. You may experience mild redness, a warm, tingling sensation, or flaking (skin exfoliation). These conditions are normal, temporary indications that the formula is working. If you experience increased discomfort when using Clinique Smart Night Clinical Md Multi-Dimensional Repair Treatment Retinol, revert to once every other night until skin adjusts. This adjustment can take up to 4 weeks. First time users and those with drier skin types may want to use Clinique Smart Night Clinical Md Multi-Dimensional Repair Treatment Retinol every other night for more than 2 weeks to give skin additional time to adjust. For added comfort, use a mild cleanser and layer an additional moisturizer over Clinique Smart Night Clinical Md Multi-Dimensional Repair Treatment Retinol. Limit sun exposure in general. Be sure to apply a sunscreen of SPF15 or higher during the day while using and one week after stopping use of Clinique Smart Night Clinical Md Multi-Dimensional Repair Treatment Retinol. Note that extreme weather conditions such as wind or cold may be more irritating, so take the proper precautions to protect your face.