Does mayonnaise really kill head lice?

Missy says…I used two lice treatments on my hair. Today I am trying to condition my hair because it is completely dry and still a little itching. I researched and mayonnaise is supposed to kill lice plus condition hair….is this true??

The Beauty Brains respond:

Can mayonnaise kill head lice? Missy, Missy, Missy. That is ridiculous! It only takes a quick search of the scientific literature to prove that using mayonnaise on lice is just a load of bull… wait a minute… There’s a study in a peer-reviewed scientific journal that suggests this might actually work? Hold the presses!

The science of suffocation

Here’s the deal. While it’s common to use pesticide-like materials to kill lice there is a newfound interest in alternative methods because lice are becoming resistant to some of the pesticides. Fortunately it turns out that lice can be killed by a method that is more physical than chemical: if you plug up the little breathing ports on their body you can actually suffocate them. The problem with this approach of course is that you have to really make sure you smother them in something. Just putting on a shower cap (like some people) suggest isn’t going to cut it.

According to the journal Pediatrics a product called DSP lotion (which stands for Dry-On, Suffocation-Based Pediculicide) uses an emulsion consisting primarily of fatty alcohols to coat the little buggers. The lotion is applied wet and then blown dry with a hair dryer. The resulting film plugs the spiracles and the lice suffocate. In the published testing the treatment was 96% effective.

Is mayo murderous?

So what about mayonnaise as a murder weapon for lice? Mayonnaise, as the cooks in our audience already know, consists of egg whites, vinegar and lemon juice. Since egg whites do have film forming properties it’s not inconceivable that they could “shrink wrap” the lice just like the DSP product. I presume to make it work properly you would also have to blow dry it on the hair to maximize the shrink wrapping effect. Fortunately, there’s nothing in the mayo that will dry out your hair.

Of course it’s also possible the level of solids in mayonnaise is NOT high enough to be effective. But, it’s certainly a cheap alternative and there’s no risk in giving it a try. If you’re more desperate for surefire solutions you can track down this DSP product.

The Beauty Brains bottom-line

Sometimes even the most seemingly outlandish statements needs to be evaluated down to see if there’s any  potential truth to it. In this case it turns out that using mayonnaise on your hair might just take care of lice after all.