One study performed in 2000 raised safety concerns about octyl methoxycinnamate by demonstrating toxicity to mouse cells at concentrations lower than typical levels in sunscreens.[medical citation needed] However, a more recent study concluded that octyl methoxycinnamate and other sun screening agents do not penetrate the outer skin in sufficient concentration to cause any significant toxicity to the underlying human keratinocytes. Estrogenic effects were noted in laboratory animals at concentrations close to those experienced by sunscreen users and were also shown in test tube experiments.[unreliable source?]
^Serpone N, Salinaro A, Emeline AV, Horikoshi S, Hidaka H, Zhao JC. 2002. An in vitro systematic spectroscopic examination of the photostabilities of a random set of commercial sunscreen lotions and their chemical UVB/UVA active agents. Photochemical & Photobiological Sciences 1(12): 970-981.