Do moisturisers cause skin cancer?
A study by Canadian researchers has produced some interesting and unexpected results. They had set out to test an idea that caffeine might help in the control of skin cancer. I am not sure where they got this idea from but the way they proposed to go about trying it out was quite logical. They exposed some hairless mice to UV radiation. This is a sure way to induce skin cancer. They were then going to run a group with the caffeine applied in a cream and a group with the cream on its own. But they were very diligent even by scientific standards and before they started they tried out the cream base on its own.
To their surprise, they found that the cream itself increased the speed at which the cancer developed. They tried three other brands of cream and got the same result.
These results surprised me as well. What didn’t surprise me was the response from the manufacturers of one of the creams who almost instantly weighed in criticising the research and trying to rubbish it. This is probably a complete waste of time. When you suggest a link between a product and cancer not many people are going to be swayed by minor methodological issues. I haven’t read the paper itself yet but it seems to have been a solid bit of work. In any case science progresses by exactly work like this. When you get an observation that contradicts your ideas then it is time to look at your ideas.
I was surprised because I know that the skin has some pretty effective protective mechanisms. These are biochemical processes that work better in well moisturised skin. So I would have expected that a moisturiser would have been beneficial. Have I completely misunderstood the situation? Well maybe. However having thought it over I think I can explain the results without having to have a major rethink. The mice were irradiated and so contracted the cancer before the cream was applied. Increasing the flow of blood and nutrients to the skin would be expected to improve the health of the skin. What I think is going on here is simply that the cancer cells are being provided with a better environment in which to grow.
My conclusion – I don’t think that there is yet any reason to think that moisturisers actually make skin cancer worse. In this experiment the cancer was actually caused by the UV, not the moisturiser. In the case of these particular hairless mice, the moisturiser speeded the development of the cancer. This effect could be a specific one whereby some particular action is being triggered off. But my opinion is that it is a much more general one. Moisturisers increase the water level in skin and this speeds up whatever biochemical processes are going on there. For the mice, this means that the cancer has a better environment to grow. On healthy human skin it is more likely to be beneficial.
I am going to carry on moisturising until there is clearer data that moisturisers are harmful. On balance, I still think that they are beneficial.
