Superoxide Dismutase - or in short SOD - is the body's smart antioxidant enzyme that protects the cells from highly reactive, cell-damaging superoxide radicals (O2−).
You have probably read the terms "free radicals" and "antioxidants" a thousand times, and you know that free radicals are the evil guys, and antioxidants are the good guys. So superoxide radical is a very common free radical that can cause all kinds of cell damages and superoxide dismutase is an enzyme that catalyzes the conversion of superoxide radicals into molecular oxygen and hydrogen peroxide (btw, this one has to be further converted by other antioxidant enzymes, called catalases).
The extra nice thing about SOD is that it remains intact during the neutralization process and can continue its magic, while non-enzymatic antioxidants (like vitamin E) are used up during neutralization.
The efficacy studies of topical SOD are promising. In-vitro (made in the lab) tests show that SOD is a more effective antioxidant than vitamin E, green tea extract, and MAP. There is also an in-vivo (made on real people) study that measured how SOD can reduce the redness caused by UV rays and it was much more effective than vitamin E (pure or acetate form) and ascorbyl palmitate.
All in all, SOD is a really potent antioxidant and slathering it all over yourself is a great way to give the skin a little extra help in protecting itself from all the bad environmental things out there.
- International Journal of Cosmetic Science, Apr 1, 2000, The future of enzymes in cosmetics