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Whether you follow the rules or not, most pet owners have heard it said that pets should never be confused for people at bath time. Shampoos, as far as the rules are concerned, are species specific.
“But why?” you may well ask. “And who makes these rules anyway?”
The truth, as with most things, lies somewhere in between how the rules read and what the hard-line skeptics say. In this case, however, I tend to side with the rule-makers. They are, after all, degreed and credentialed dermatologists who didn’t come up with their rules just to turn a buck off “Fluffy’s Finest Scrub-A-Dub Shampoo.”
Why use pet shampoo?
Here’s the simple explanation for why human shampoos and pet shampoos are not created equal: Pet skin and human skin are not alike in many ways. Here are the two we tend to care most about when it comes to shampoos:
People skin is more acidic than pet skin.
People have sweat glands and pets don’t (not on their haired skin, anyway).
While there are more differences, and some of them do impact the chemical makeup and consistency of shampoo formulas, these are the most commonly cited. Perhaps that’s because a shampoo that’s too acidic (because it’s pH balanced for humans) and/or too harsh (because it’s designed for those with moister skin) can lead to dryness and irritation, the most oft observed outcomes of an inappropriate shampoo selection.
Why pets need certain shampoo
The skin is a major organ that plays a huge role in immunological defense. By drying the skin we’re stripping the oils and the top layers from an animal’s skin, thereby compromising the body’s natural barrier against infection. And when these defenses are disrupted, the skin –– indeed, the entire pet –– can become predisposed to infections. This is usually caused by the yeast and bacteria that live on the surface of the skin.
The risk of a contact irritation is always a possibility too, whether we’re dealing with pet products or human formulas. With pet shampoos, however, manufacturers will have typically undertaken simple trials on pets to determine whether the risk of such an irritation is likely, whereas human shampoos are seldom (if ever) tested on domesticated pets (and certainly never with the goal of protecting them from any harm).
Not All Shampoos Are Bad
Pet owners commonly ask, “how does that explain the fact that I’ve always used my own shampoos on my dogs and never once witnessed a reaction?”
The truth is that not all human shampoos will react adversely with pet skin. Here are a few reasons why:
The variability in the pH of pet skin - which can differ dramatically among certain breeds of dogs- may be one explanation. In this case, your Schnauzer’s more acidic skin might do well with your own shampoo, while your Lab’s might get all red and flaky.
Many adverse reactions are frequency dependent. In other words, you may not be using the shampoo often enough to see a bad reaction.
Moreover, a very soiled and dirty pet might well require a stronger (“harsher”) cleanser to get all the stuff off. And if you don’t use a ton of shampoo, you might not be putting the skin at much of a risk at all.
Individual variations in the skin of pets can make all the difference. That’s why some pets will seem “overly-sensitive” to shampoos while others can take just about any shampoo you throw at them.
So should you use human shampoo on your pet?
As a veterinarian, my personal preference is all about reducing risk. Which only makes sense seeing as I tend to only treat pets who’ve suffered reactions. And how much cheaper is the human stuff, anyway? Why NOT use the pet specific shampoos?
Having said that, it’s also the case that pet shampoos can prove equally, if not more problematic for certain pets. Turns out that, as with pet nutrition, this is one area where there are no guarantees that a product will work well for you. As with many other things in your pet’s life, common sense –– along with trial and error –– is probably your best approach.