PABA, or para-amino-benzoic acid, is a popular additive to many organic beauty products, but it's not as harmless as it seems. Not many of us are aware that PABA is chemically related to parabens, which are esters of para-hydroxy-benzoic acid.

PABA has traditionally been used as a sunscreen; however, Swiss researchers found that PABA increases damage the ultraviolet damage to the DNA in human cells due to a complex process of energy transfer to human cells, thus increasing the risk of skin cancer.

(Source: Photochemical mutagenesis: examples and toxicological relevance. Gocke E. Journal of Environmental and Pathological Toxicology and Oncology. 2001;20(4):285-92.)