We're probably all guilty of the occasional surreptitious "pit check" to make sure that our deodorant is working, especially when we're outside in hot weather or in a really stressful situation. The mere thought that somebody might catch a whiff of our body odor is enough to embarrass us. Some of us are loyal to specific brands of deodorant, while others buy whatever's on sale and apply it without much thought. But what if your deodorant doesn't seem to be working quite the way that it used to? Is it possible that your body can adjust to a specific deodorant, necessitating a switch?

When we say "deodorant," we're often talking about a single product that contains both a deodorant and an antiperspirant, although there are also products that are just deodorants. Deodorants contain ingredients to make the skin hostile to the sweat-eating bacteria that create odor, as well as perfumes to mask any smell that still gets produced. Antiperspirants are supposed to keep us from sweating, or perspiring, entirely. Essentially, they plug up the pores through which sweat is excreted, typically with an aluminum compound (to learn more, check out What is it in antiperspirant that stops sweat?). We'll just use "deodorant" here to mean deodorant/antiperspirant.

The argument that you should switch deodorants might stem from a similar one about shampoos. While some experts believe that occasionally changing your shampoo is necessary for healthy hair, others don't think it makes a bit of difference. However, there's no definitive proof that your hair "gets used to" a specific hair product. The same holds true for deodorants -- no one has proven that your body can actually adjust to it over time.

Your regular brand of deodorant might be failing you for other reasons that have nothing to do with your body getting used to it. Next, we'll look at some possible causes and what to do about it.