According to our experts, the vitamin C type will also determine its effectiveness. Pure vitamin C, known as L ascorbic acid, ...

Of all the vitamin-C options, our experts generally recommend looking for serums that contain ascorbic acid, also known as L-ascorbic acid, which is the most active and purest form of vitamin C.

C. Ascorbic acid as a sensor of oxidative stress and a regulator of gene expression: The Yin and Yang of Vitamin C. Med Hypoth 69, 953–954 (2007). Grollman, A. P. & Lehninger, A. L. Enzymic ...