Vitamin C is one of the most well-researched and beneficial vitamins you can apply topically. Ongoing use has been shown to improve the look of multiple signs of aging, brighten an uneven skin tone, as well as provide skin-restoring and soothing benefits. [1,2,3]
Vitamin C comes in many forms, with ascorbic acid being the most well-researched for its efficacy. Learn more about ascorbic acid’s benefits here.
Other forms of vitamin C you will see included in skincare products include magnesium ascorbyl phosphate, L-ascorbic acid, tetrahexyldecyl ascorbate, ascorbyl palmitate, ascorbyl glucosamine, and ascorbyl tetraisopalmitate. In any form, vitamin C provides potent antioxidant protection, shielding skin from damaging environmental stressors. 
Note: All antioxidants, including vitamin C, are vulnerable to destabilizing when exposed to air and light. That means if you want to reap the reward of your antioxidant-enriched treatments, only choose those that are packaged in opaque tubes, air-restrictive bottles, or pumps that help keep their ingredients stable.
- Campos P, Goncalves G, Gaspar L. In vitro antioxidant activity and in vivo efficacy of topical formulations containing vitamin C and its derivatives studied by non-invasive methods. Skin Res Technol. 2008;14(3):376-80.
- Farris P. Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions. Dermatol Surg. 2005;31:814-7.
- Chen L, Hu JY, Wang SQ. The role of antioxidants in photoprotection: a critical review. J Am Acad Dermatol. 2012;67(5):1013-24.