Retinoids thicken your skin and fend off wrinkles by increasing collagen and elastin production - so use one nightly. There are over 700 published studies that have proven how good these skincare products are for skin. Retinoids are a form of Vitamin A that speed up collagen production (which reduces wrinkles) and even out skin tone. If you have dark spots on your skin, they'll reduce them. The higher the percentage of retinol (the over the counter version), the better the result. Learn more here: https://masterpieceskinrestoration.com/blog/prevent-wrinkles-colorado/