Alpha lipoic acid is an enzyme that shown to be an excellent antioxidant when applied topically to the skin. When taken orally, alpha lipoic acid is a water- and fat-soluble antioxidant that can regenerate other antioxidants like Vitamin C and Vitamin E. It is also thought to have a variety of soothing properties.

The research shows that alpha lipoic acid is a powerful antioxidant, but it isn't the only one; there are many other great antioxidants for skin—in reality, there hasn't been much research on the topical application of alpha lipoic acid.

There is some evidence that it can cause cell signalling at higher concentration. However, at this concentration (5% or higher), it can cause irritation and a burning or stinging sensation on the skin.

Alpha lipoic acid is also extremely sensitive to degradation by sunlight.