What product is best for fading dark spots on face skin?

Hydroquinone. A very common treatment for unwanted pigment is hydroquinone. However, remember that even if it works you still have to use sunscreen. The dark spots can come back if you don't. Retinoids can also help to fade skin pigment but they can also be a little irritating and cause some peeling. Seeing a dermatologist will help you come up with the right treatment for you.