Isododecane is a common ingredient found in cosmetics, skin care and body care. Isododecane is primarily used to keep products soft and easy to apply. Isododecane is a colorless liquid used as an emollient in products such as mascara, eyeliner, lip gloss and hair spray. Isododecane is used in many different cosmetic formulas due to its low incidence of side effects and because the skin can not absorb it and therefore can not cause irritation.