There is no correct answer to this. You see, glycolic (in addition  to other Alpha Hydroxy Acids) and retinol have completely different functions. While retinol is mainly suited in stimulating cell regeneration as well as the synthesis of elastin and collagen, glycolic is majorly suitable for cleansing purposes and removing debris from the skin. In other words, if you are looking to address and prevent wrinkles, fine lines and damage then retinol is your best bet. On the other hand, those who want to address oiliness, clogged pores and uneven texture will be best served with glycolic.