Researchers at Rutgers University, New Jersey, exposed mice to large doses of UVB radiation to make them at high risk of developing skin tumors and then applied four widely used moisturizers to the animals every day for several months.
In a study published in the Journal of Investigative Dermatology they found the number of non-melanoma tumors was significantly higher in the mice treated with cream than the control group.
Different products, different results
Significant differences were also observed between the moisturizers.
Dermabase by Paddock Laboratories, Dermovan by Healthpoint, Eucerin Original Moisturizing Cream by Beiersdorf and Vanicream by Pharmaceutical Specialties were all put under the microscope.
Tumor rates increased 95 percent with Dermovan and only 24 percent with Eucerin leading the scientists to conclude that certain ingredients were responsible for the higher risk levels.
They prepared a custom blend without several suspect ingredients such as sodium lauryl sulfate and found that cancer rates were significantly lower.
Doubts about relevence to humans
Leading study author Allan Conney said further studies were needed to determine whether the conclusions could be extended to apply to humans exposed to sunlight.
Rodent skin is far more sensitive than human skin and for the purposes of the experiment strong UVB light rather than natural sunlight was used before the moisturizers were applied.
"Tumorigenic Effect of Some Commonly Used Moisturizing Creams when Applied Topically to UVB-Pretreated High-Risk Mice."
Yao-Ping Lu, You-Rong Lou, Jian-Guo Xie, Qingyun Peng, Weichung J. Shih, Yong Lin and Allan H. Conney.Journal of Investigative Dermatology, Advanced online publication, 14 Aug 2008.DOI:10.1038/jid.2008.241