1, sunscreen itself has a high oil content, and there are sunscreens such as zinc oxide and titanium dioxide, and there must be preservatives and the like. If you stay overnight, it is easy to block pores.
2. Sunscreen often contains 3- benzylidene camphor, which is easily absorbed by the human body if it is rubbed overnight. The French Health Products Safety Agency (AFSSAPS) announced an emergency ban, requiring manufacturers to ban the use of 3- benzylidene camphor (3-BC) in cosmetics because of its potential risk of interfering with human endocrine.
ChemSec, a government organization, welcomed the decision and called on France to list 3- benzylidene camphor as substances of very high concern (SVHC) according to REACH regulations. ChemSec said that 3- benzylidene camphor is often used as an ultraviolet filter in sunscreen and can be absorbed by the human body through the skin. 3-BC has been found in pregnant women's breast milk.
AFSSAPS also said in the resolution statement that recent studies show that 3-BC will interfere with endocrine, especially affect fertility problems, and cosmetics containing this substance may cause serious harm to human health.
Extended data:
Recently, Wang Baoxi, chief physician of Plastic Surgery Hospital of China Academy of Medical Sciences, said in the live broadcast of popular science consultation on the client of "People's Good Doctor" that unopened sunscreen can still be used normally within the validity period as long as it is well sealed and properly preserved. "After using the used sunscreen for another year, the matrix inside may change. It is not recommended to continue using it."
Wang Baoxi explained that the physical protective components in sunscreen, such as zinc oxide and titanium dioxide, will not deteriorate and fail for a long time. However, other ingredients in sunscreen may deteriorate due to high temperature or exposure to air, resulting in serious bacterial growth and deterioration.
References:
People's Daily Online-Can sunscreen be used after one year's storage?
References:
Phoenix net-apply sunscreen, be careful not to interfere with endocrine.