Parabens: An endless story

Parabens were introduced in the 30s and currently represent the most common preservatives in cosmetics, in topical as well as systemic drugs, and in alimentary products. Chemically, they are p-hydroxybenzoic acid alkylesters. Methyl, ethyl, propyl and butylparaben are frequently used, the former two especially. Their great popularity results from a series of useful properties: they are inexpensive, odorless, tasteless, colorless and show a wide anti-bacterial spectrum. Parabens have always been cause of argument, first because of their sensitizing capacities, and recently given their presumed mammary cancerogenic potential and hormonal interferences. From an allergological perspective, parabens constitute weak sensitizers. As a matter of fact, contact allergy incidence to these substances has always been low, and today reaches negligible levels, given their banning from most cosmetic products. Contact allergy highest percentages used to be associated to topical parabens containing drugs which were applied on lesional skin (wounds, ulcers, preexisting contact dermatitis). Percentages have conversely always been low following use of cosmetic products on healthy skin. A recent literature review ruled out parabens responsibility (as contained in antiperspirants) in mammary cancer determinism. These compounds have also been suspected to interfere with sexual hormones. At recommended doses, however, methyl and ethylparaben do not show any hormonal effects in humans. Further studies concerning propyl and butylparaben are advisable, given their possible fertility impairing effect in males which were exposed during their childhood.