Subungual penetration of dibutyl phthalate in human fingernails

Dibutyl phthalate (DBP) has a wide variety of manufacturing applications and is used in both commercial and consumer products. Results of animal reproductive toxicity and teratogenicity animal studies have not been consistent in identifying DBP as a reproductive toxicant. Expert reviews for its use in consumer products have consistently concluded that it is not a reproductive risk to consumers. Results from a subungual penetration study of 100% fluid DBP applied to human fingernails showed levels of penetration at the limits of chemical detection. Even if DBP penetrated the human fingernail, its rapid metabolism by the human body would prevent its having any toxic reproductive effects. Furthermore, DBP functions as a plasticizer in consumer products such as cosmetic nail products (nail polish, basecoats, topcoats, nail hardeners), resulting in its becoming unavailable for subungual penetration seconds after application of the cosmetic nail product since it is then trapped in the rapidly forming coating.