1. From low to high concentration
Retinol should be applied 1 nights per week to start. If the skin isn’t irritated by it, After 2 week, move up to 2 nights a week. After 4 week, move up to 3 nights a week. After 6 week, move up to 4 nights a week. After 9 week, change to use every day. After 11 week, start with a retinol 0.5.
If you have sensitive or dry skin, it is recommended that you use a lower strength retinol product and start with only using it a few days per week. Slowly, you can build up to using it every night.
2. Use Retinol Only at Night and Wear SPF Every Day
"Retinol makes your skin more sensitive to UV rays and sunlight decreases the efficacy of the product," only use retinoids at night and be diligent about applying a daily broad-spectrum SPF 30 or higher during the day.
3. Don’t use with AHA/BHA
During this period of using retinol, the skin may be weaker, at this time, don't use AHA/BHA at same time to avoid more irritation to the skin.
4. Is Retinol Safe For Pregnant?
Maternal use of synthetic vitamin A (retinoids) such as isotretinoin (Accutane) during pregnancy can result in multiple effects on the developing embryo and fetus including miscarriage, premature delivery and a variety of birth defects.