Final Report on the Safety Assessment of Benzaldehyde1

Abstract

Benzaldehyde is an aromatic aldehyde used in cosmetics as a denaturant, a flavoring agent, and as a fragrance. Currently used in only seven cosmetic products, its highest reported concentration of use was 0.5% in perfumes. Benzaldehyde is a generally regarded as safe (GRAS) food additive in the United States and is accepted as a flavoring substance in the European Union. Because Benzaldehyde rapidly metabolizes to Benzoic Acid in the skin, the available dermal irritation and sensitization data demonstrating no adverse reactions to Benzoic Acid were considered supportive of the safety of Benzaldehyde. Benzaldehyde is absorbed through skin and by the lungs, distributes to all well-perfused organs, but does not accumulate in any specific tissue type. After being metabolized to benzoic acid, conjugates are formed with glycine or glucuronic acid, and excreted in the urine. Little acute toxicity was seen. The oral LD50 of Benzaldehyde in rats and mice ranged from 800 to 2850 mg/kg. The intraperitoneal LD50 in white rats was 3265 mg/kg. In short-term oral studies, the no observed adverse effect level (NOAEL) was 400 mg/kg in rats and mice. In subchronic oral studies, the NOAEL was 400 mg/kg in rats and 600 mg/kg in mice. In a 16-week feeding study, rats given up to 10,000 ppm showed no signs of toxicity. Repeated inhalation of volatilized Benzaldehyde produced ocular and nasal irritation at 500 ppm and death in rabbits at 750 ppm. Undiluted Benzaldehyde was irritating to rabbit eyes, causing edema, erythema, and pain. Benzaldehyde was determined not to be a contact sensitizer, but did produce allergic reactions in a maximization test. Clinical reports of allergy to Benzaldehyde are rare. Benzoic Acid did not produce irritation or sensitization reactions in human clinical studies. Benzoic Acid also failed to produce reactions in phototoxicity and photosensitization tests. Neither Benzaldehyde, Benzoic Acid, nor Sodium Benzoate are reproductive or developmental toxicants at doses that are non-toxic to the mother. In a behavioral study, blood levels of 0.12 ng/ml Benzaldehyde produced a 44% reduction in motor activity in mice. Benzaldehyde did not produce mutations in bacterial assays, but did produce chromosomal abnormalities in Chinese hamster cells and increased mutations in a mouse lymphoma forward mutation assay. Benzaldehyde was evaluated by the National Toxicology Program, which found no evidence of carcinogenicity in rats, and some evidence of carcinogenicity in mice. Several studies have suggested that Benzaldehyde can have carcinostatic or antitumor properties. Overall, at the concentrations used in cosmetics, Benzaldehyde was not considered a carcinogenic risk to humans. Although there are limited irritation and sensitization data available for Benzaldehyde, the available dermal irritation and sensitization data and ultraviolet (UV) absorption and phototoxicity data demonstrating no adverse reactions to Benzoic Acid support the safety of Benzaldehyde as currently used in cosmetic products.