Differing Dark Spot Correcting Serum is formulated with 2% Hydroquinone Skin Lightener — a maximum-strength skin lightening ingredient available without a prescription — to improve overall luminosity and gradually fade darker discoloration, post-acne marks, blotches and hyper-pigmentation. Post-acne marks are a common issue for acne sufferers. By brightening those areas, skin can appear more even and clear.