Group of fungi that ferment sugars. Yeast is a source of beta-glucan, which is a good antioxidant. Yeasts are basically fungi that grow as single cells, producing new cells either by budding or fission (splitting). Because it reproduces readily, Saccharomyces cerevisiae is the organism that is most widely used in biotechnology. Nevertheless, some forms of yeast are human pathogens, such as Cryptococcus and Candida albicans.
In relation to skin, there is limited information about how S. cerevisiae may provide a benefit. Live yeast-cell derivatives have been shown to stimulate wound healing, but research about this is scant.  Much of what is known about yeast’s effects on skin is theoretical, and concerns yeast’s tissue-repair and protective properties or yeast’s antioxidant properties.  As a skincare ingredient yeast has potential, but what its function may be or how it would affect skin is not fully understood.
- Bentley J, Hunt T, Weiss J, Taylor C, Hanson A, Davies G, Halliday B. Peptides from live yeast cell derivative stimulate wound healing. Arch Surg. 1990;125(5):641-6.
- Bennett C, Lewis L, Karthikeyan G, Lobachev K, Jin Y, Sterling J, Snipe J, Resnick M. Genes required for ionizing radiation resistance in yeast. Nat Genet. 2001;29(4):426-34.