Researchers in the US found that several moisturisers commonly used by consumers increased non-melanoma skin cancers in mice that had been exposed to ultra violet radiation.

The study is published in the 14 Aug 2008 advanced online issue of the Journal of Investigative Dermatology and was the work of Dr Allan Conney and colleagues from the Susan Lehman Cullman Laboratory for Cancer Research at the University of New Jersey.

Conney and colleagues said people should not get alarmed about these results since mouse skin is not the same as human skin, although the findings might explain some types of skin cancer in humans.

According to New Scientist, Conney told the press that:

“We don’t know whether or not there’s an effect in people.”

He explained that they discovered the effect by accident. They were investigating the effect of caffeine on the development of skin cancer and happened to use moisturising cream as the carrier, but then they found the cream itself had unexpected tumorigenic activity.

The researchers then went on to test four common moisturisers: Dermabase, Dermovan, Eucerin and Vanicream, on hairless albino mice that had been bred to test sunlight-triggered non-melanoma skin cancer in humans. The mice were exposed to UV radiation twice a week for 20 weeks, which put them at a high risk of developing non-melanoma skin cancer (the non lethal type of skin cancer). Some mice were treated with moisturisers and some were not.

The mice treated with moisturisers developed more, larger tumors (non-lethal basal cell and squamous cell carcinomas) at a faster rate than the mice that were not treated with moisturisers. As Conney explained:

“We tested a total of four moisturising creams, and all four of them had tumorigenic activity.”

The researchers suspected that the ingredients most likely to have caused the tumors were mineral oil, which has been shown to have this effect in other animal studies and a known irritant, sodium lauryl sulphate, which is a very common ingredient in cosmetic, personal hygiene, and other household and pharmaceutical products where it is used to thicken creams and also to create lather, among other things.

Conney and colleagues then made their own cream that excluded these two ingredients (they have filed a patent for it) and found it did not produce the increased tumorigenic activity of the creams that did include the two products. However, the findings are not conclusive in that other creams that did not have these two ingredients also showed increased tumorigenic activity.

Experts not involved in the study have echoed the authors’ sentiments that these results are not cause for alarm since many more studies on humans are needed to find out if moisturisers have similar effects on human skin.

“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

Click here for Journal of Investigative Dermatology.

Sources: European Institute of Oncology, New Scientist.

Written by: Catharine Paddock, PhD