Undecylenoyl Phenylalanine

Undecylenoyl Phenylalanine is a lipoamino acid used in skincare often marketed to have skin brightening effects. It is also known as Sepiwhite MSH.

In lab and skin-model studies, this ingredient helps regulate how much pigment (melanin) the skin makes. It works by interfering with signals that tell pigment cells to “turn up” melanin production instead of bleaching or stripping pigment that’s already there.

It should be noted that most studies look at finished skincare formulas and not the ingredient on its own.

Products containing undecylenoyl phenylalanine have been shown to help improve the appearance of dark spots, discoloration, and uneven skin tone with regular use, especially when used consistently over several weeks.