Gerd Ries

Retinol: Safety Considerations for its Use in Cosmetic Products

AbstractBased on the published literature, the assessment of nonclinical and clinical data on retinol indicates absence of any systemic effects after topical or cosmetic use. Hypervitaminosis A that may be produced by the ingestion of excessive amounts of retinol or retinyl esters has never been associated with topical application. In rabbits treated with retinyl palmitate at about three times a prospective human dose level, no systemic toxicity was observed. Retinol, retinyl esters, and retinaldehyde are devoid of sensitization potential and no evidence of phototoxicity or photoallergy has been obtained. Although retinoids may be degraded to some extent by sunlight, their biological activity appears to be largely retained. In fact, topical retinoids have been shown to improve the conditions of photodamaged and photoaged skin. Topical retinol is absorbed into the epidermis and extensively metabolized, particularly by keratinocytes. Studies in human volunteers provided no evidence that topically applied re...

Safety and Efficacy of Elubiol in Cosmetic Use

Abstract Elubiol (dichlorophenyl imidazoldioxolan) is used as a cosmetic ingredient for the conditioning of oily skin. It was found in controlled and open clinical trials to control sebum output effectively at the skin surface. In vitro testing has indicated a potential of reducing cholesterol biosynthesis, thus modulating the lipid composition of sebum; of antimicrobial activity against organisms associated with dandruff or seborrhea; and of scavenging free radicals. Elubiol is well tolerated and no systemic toxicity is observed on dermal application. There is no evidence of sensitization potential in vivo, nor of specific irritancy or phototoxicity in vitro. A standard battery of tests revealed no genotoxic potential. Topical Elubiol hardly penetrates into the epidermis and there is no evidence that percutaneous absorption occurs, as confirmed by studies in animals and humans. In the absence of systemic exposure, Elubiol is considered to be a safe ingredient for cosmetic use.