Skin care products containing vitamin A derivatives and analogs such as retinol as well as those containing glycolic and other alpha hydroxy acids have been scientifically proven to help rejuvenate the skin. Other products including those containing vitamins C, D, and E may also help rejuvenate the skin and limited scientific evidence confirms their value. Sunscreens, of course, are a key part of any complete skin rejuvenation program since sun exposure is the main cause of skin aging.