Lactobacillus/Pear Juice Ferment Filtrate

This ingredient is exactly what it sounds like: pear juice fermented with the Lactobacillus bacteria (the bacteria is filtered out of the final product).

The main thing that comes out of this process is lactic acid, an AHA.

Lactic acid is one of the more well-studied AHAs in skincare:

• It provides a mild exfoliation by loosening the bonds that hold dead skin cells together to smooth texture
• It is part of your skin's own Natural Moisturizing Factor (NMF) and also acts as a humectant
• L-lactic acid can boost ceramide production in the stratum corneum, or outermost layer of skin

Fermentation also adds some bonus phenolic compounds with antioxidant activity.

The only catch with this ingredient is that it is difficult to tell how much lactic acid is in any given product. Ferment filtrates don't come with standardized acid concentration like a 5% lactic acid serum would; this just means the actual exfoliating effect will vary depending on the formula's overall percentage and pH.

Remember that AHAs make your skin more sun-sensitive, so be sure to wear sunscreen.