Phenylethyl Resorcinol

Also-called-like-this: SymWhite
What-it-does: antioxidant, skin brightening

A skin-lightening and antioxidant active ingredient derived from a molecule that exists naturally in Pine tree. According to the clinical results of the manufacturer, 0.5% of phenylethyl resorcinol is more effective than 1% of well-known skin-lightener kojic acid. 

Though the results from the manufacturer sound quite promising, a skin-lightening study from 2013 involving phenylethyl resorcinol shows quite moderate results. In the 80 participants, 12-week study, phenylethyl resorcinol was combined with three other actives (disodium glycerophosphate, L-leucine, and undecylenoyl phenylalanine) and only 57% of the participants showed at least a moderate response and 17% did not improve at all.