A study conducted by Center for Drug Evaluation and Research showed that it takes just one day for harmful ingredients in sunscreen to enter the blood stream. The four chemicals include, Avobenzone, Oxybenzone, Ecamsule and Octorylene. The study was published in the medical journal, JAMA.
According to an article by CNN, the blood concentration of three of these chemicals continued to rise with daily use and remained in the body 24 hours after the use of sunscreen ended.