Glutamic Acid(1,300 Ppm)
Glutamic acid is a small, non-essential amino acid (CAS 56-86-0) that the body can synthesize on its own and that serves as a neurotransmitter in the nervous system. In cosmetics it functions primarily as a humectant moisturizer and skin-conditioning agent. It exists in two distinct mirror-image forms, L-glutamic acid and D-glutamic acid, which appear to have opposing effects on skin barrier repair. It can also act as a pH adjuster and can be metabolically converted into pyrrolidone carboxylic acid, a component of the skin's natural moisturizing factors.
Glutamic acid attracts and retains moisture in the skin as a humectant. It can be processed into pyrrolidone carboxylic acid (a natural moisturizing factor), supporting skin hydration. Its D-form has been associated with accelerated skin barrier repair in study conditions, though the L-form showed the opposite effect.
The ingredient exists as two distinct isomers (L- and D-glutamic acid) with opposing effects on skin barrier repair: topical L-glutamic acid has been shown to delay repair of damaged skin, while D-glutamic acid sped it up. Because ingredient lists typically do not specify which form is used, the net effect on barrier repair is uncertain.
