Extract of plants that is used in cosmetics primarily for fragrance. A few animal studies and some in vitro research investigated farnesol’s antibacterial and anti-cancer properties. [1,2] It may also have some antioxidant properties, but there is no research showing it has any benefit on skin. 
- Akiyama H, Oono T, Huh W, Yamasaki O, Ogawa S, Katsuyama M, Ichikawa H, Iwatsuki K. Actions of farnesol and xylitol against Staphylococcus aureus. Chemotherapy. 2002;48(3):122-8.
- Chaudhary S, Alam M, Siddiqui M, Athar M. Chemopreventive effect of farnesol on DMBA/TPA-induced skin tumorigenesis: involvement of inflammation, Ras-ERK pathway and apoptosis. Life Sci. 2009;85(5-6):196-205.
- Machida K, Tanaka T, Fujita K, Taniguchi M. Farnesol-induced generation of reactive oxygen species via indirect inhibition of the mitochondrial electron transport chain in the yeast Saccharomyces cerevisiae. J Bacteriol. 1998;180(17):4460-5.