Cis-urocanic acid is primarily studied for its role in the skin's immune response. It is a derivative of histidine and is formed in the epidermis upon exposure to UV radiation. This compound acts as an immunosuppressant, helping to modulate the immune system to prevent overreaction to UV-induced damage. It is also being researched for its potential applications in dermatology, particularly in understanding and managing conditions like skin cancer and photoaging. Additionally, cis-urocanic acid is explored in the context of its effects on inflammatory responses and its possible use in developing treatments for autoimmune diseases.