Tretinoin (generic name for Renova, Retin A, etc) is very safe long term.  It has been studied for over 20 years and millions of people use it regularly.  It helps with wrinkles, improves sun damaged skin, and helps to prevent skin cancer.  It's hard to go wrong with it.  It may make you just slightly more sun sensitive.  You may want to stop it a week before a sunny vacation or times when you're in the sun a lot like summer unless you are compulsive about sunscreen and hats. Dr. I