TruSkin's popular Vitamin C Serum, said to help brighten and even skin tone, is currently on sale at a 65% discount ...

What it costs: Medik8 is a little on the pricier side but certainly far from outrageous. The brand’s products all cost ...

“With both types of over-the-counter products ... own control group by applying HPE serum to their right hand and vitamin C ...

Vitamin C and retinol (a form of vitamin A ... However, retinol is a gentler formulation usually found in over-the-counter ...