A new study shows that ingredients used in some moisturizers used by millions of people may actually trigger skin cancers themselves – and the explanation offered by the researchers conflicts with earlier reports used to slam tanning.

Scientists at Rutgers University showed that four common skin creams increased the incidence of non-melanoma skin tumors in gene-altered hairless mice when the mice were exposed to UV light. According to the study, published in the Journal of Investigative Dermatology, skin cancers increased between 24 and 95 percent in mice treated with the creams compared to mice not treated with the skin creams.

The skin cream ingredients Dermabase, Dermovan, Eucerin and Vanicream were tested in the study. According to WebMD:

• Dermabase increased the total number of tumors by 69%.
• Dermovan increased the total number of tumors by 95%.
• Eucerin increased the total number of tumors by 24%.
• Vanicream increased the total number of tumors by 58%.

Gordon McVie, a senior consultant at the European Institute of Oncology, told European news service AFP: “This has no relevance to causation of human skin cancer and does not prove in any way whatever that moisturizing creams are cancer-causing in humans.”Indeed, the study’s authors “cautioned that rodent skin is more sensitive than human skin, while other experts said they had reservations about the relevance of the study’s conclusions,” AFP reported.

So what’s the big deal?

“It’s interesting that when researchers were using hairless mice years ago to attempt to show that tanning caused skin cancer the researchers didn’t point out that studies on these same hairless mice should not be translated to humans,” Smart Tan Vice President Joseph Levy said. “They felt perfectly comfortable back then applying those results to humans. But now when it comes to protecting the interest of those who over-market sunscreen usage, we’re hearing that hairless mice studies don’t apply to humans. That’s a convenient double-standard.”

To read the AFP report click here.

To read WebMD’s coverage of the study click here.