Evidence based footcare

I'm training for a marathon at the moment (and it's in aid of Cancer Research UK, which is an excellent cause, so please sponsor me here), and all the running has given me some nasty blisters on my feet.

So I went to see a podiatrist yesterday to try to make sure that the blisters are under control in time for the big day. She put a dressing on which seemed to make my blisters pain free on my run this morning, which is a good start.

However, she also recommended that I use a product called "Trek Bliss" foot cream, which she told me would help to improve the quality of my skin and make me less prone to a recurrence of blisters. When I asked her if that had been demonstrated in any randomised controlled trials, she looked rather surprised, and admitted that she didn't know. I guess she isn't used to treating medical statisticians. I then asked how she knew that it worked, to which she replied that many of her other clients come back for more of it. Not very convincing. Most homoeopaths probably also say that their clients come back for more, so that's really no better than no evidence at all of efficacy.

I've just done a fairly careful search on both PubMed and Google Scholar, and couldn't find any evidence whatsoever that this cream will have the desired effect. I've emailed the manufacturer to ask if they have any evidence, but I suspect that the answer will be that they don't.

So, right now I'm thinking that I should use the cream on one foot only between now and when I run the marathon and see if that foot has any fewer blisters than the other. Could I ever respect myself as a scientist again if I did anything else?