Enzacamene
Enzacamene (INN; also known as 4-methylbenzylidene camphor or 4-MBC) is an organic camphor derivative that is used in the cosmetic industry for its ability to protect the skin against UV, specifically UV B radiation. As such, it is used in sunscreen lotions and other skincare products claiming a SPF value. Its tradenames include Eusolex 6300 (Merck) and Parsol 5000 (DSM). Mechanism. All the camphor-derived sunscreens dissipate the photon energy by cis-trans isomerisation. However, for enzacamene the quantum yield for this isomerization is only between 0.13-0.3. This low quantum yield means that other photochemical processes  are also occurring. Endocrine disruptor. Studies have raised the issue that enzacamene acts as an endocrine disruptor. There is controversy about the estrogenic effects of enzacamene and while one study showed only a relatively minor effect. In addition, there is some evidence that enzacamene may suppress the pituitary-thyroid axis, leading to hypothyroidism. Approval status. Enzacamene is approved in Canada by Health Canada. It is not approved for use in the United States by the Food and Drug Administration and it is not permitted in Japan nor in Denmark.