Urocanic acid

Urokanic acid, a white solid with the molecular formula C6H6N2O2, is an organic chemical substance that is a component of human sweat.

Urocanic acid is a breakdown product of histidine. The substance is photoprotective and plays an important role in protecting the skin from UVB radiation. Urocanic acid initially occurs in the skin as trans-urocanic acid and is partially converted into its cis isomer upon irradiation with UVB light (Landeck L et al. 2016)

Cosmetics: Urocanic acid is used in cosmetic formulations as a light protection agent. It acts as UVB filter (Mollet M et al. 2017).

Medicine: In smaller studies in patients with atopic dermatitis an improvement of skin inflammation and an improvement of the transepidermal water loss -TEWL could be achieved with a 5% urocanic acid cream (Peltonen JM et al. 2014)

1. Landeck L et al (2016) The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation. Photodermatol Photoimmunol Photomed 32:214-223.
2. Mollet M et al (2017) New nature-inspired urocanic acid mimic preventing DNA damages and immunosuppressive signalling induced by ultraviolet B radiation. J Cosmet Sci 68: 99-106.
3. Peltonen JM et al (2014) Three randomised phase I/IIa trials of 5% cis-urocanic acid emulsion cream in healthy adult subjects and in patients with atopic dermatitis. Acta Derm Venereol 94:415-420.