WHAT IS THE DIFFERENCE BETWEEN PET SHAMPOO AND HUMAN SHAMPOO?
The bottom line is that although there are some major differences between a top shelf human shampoo and an economy pet shampoo, there are a great many middle range products that are quite similar. Some of the more sophisticated pet shampoos have formulas that are nearly identical to their human counterparts. The human and canine skin and hair may be somewhat different, but the similarities between the two species are greater than the differences and the same goes for the shampoos.
Human Shampoos Have More Additives
A broad difference between shampoos for pets and those for humans is that human shampoos tend to have more additives in them, but some of the premium pet shampoos are catching up. Basically, a shampoo contains: water, a cleansing system (surfactants), a thickening / foam building system (more surfactants), a preservative system, and the additives. The additives are ingredients that give a shampoo its unique character, including colour and fragrance. Together, they usually make up no more than 2-5 percent of the product. When I first started grooming in the ‘70’s, pet shampoos were fairly simple formulas, often no more than four or five ingredients. Nowadays it is not unusual to find pet shampoos with more than 10 ingredients.
Conditioning ingredients, such as Cetrimonium Chloride and Dimethicone, are functional additives that provide anti-static, detangling and hair softening benefits. It’s hard to find a human shampoo without some type of conditioning additive, and pet shampoos are following suit. One additive that is popular in pet shampoos that is not often found in human formulas is Oatmeal. It has become a fad ingredient in pet products. Some additives are present primarily for marketing value because consumers recognise them as having certain qualities. An example is Aloe Vera.
This additive is synonymous with “soothing” and “moisturising”. While it is sometimes a functional additive in significant quantity, it is often present in “pixie dust” amounts so that the manufacturers can put it on the label. This has become true of Oatmeal in pet shampoos. Protein additives, such as Hydrolysed Wheat Protein, are becoming popular in pet shampoos. These ingredients fill in the cracks and crevices in the hair cuticle, temporarily smoothing and adding an appearance of greater volume. Fragrance additives have become a huge trend in both marketplaces. When I started grooming our pet shampoos had just enough fragrance in them to cover up the odour of the basic ingredients. Now groomers are asking for more heavily fragranced shampoos and want a fragrance that lasts for days. The downside to this fragrance trend is that fragrance ingredients in human products have been identified as the most frequent cause of allergic reactions. It is logical that this holds true for pet products as well. And fragrance-extending ingredients are most likely phthalates, which are problematic as possible cancer-causing substances.
Differences in pH
Much ado is made on the matter of the alleged differences in the pH of products designed for pets, with implication that to use off-label products could be harmful. This is a lot of mythology, created to steer people away from using human products and to sell products labelled for pets. Actual measurement by this author of over 60 pet and 45 human shampoos revealed that there were more significant differences in pH within each group than there were between the two groups.
Pet Shampoos Are More Concentrated
The hypothesis about pet shampoos being more concentrated may hold up for some products, but not for all. Many premium human shampoos have about the same percentage of “solids” (i,e, ingredients other than water) as do many pet shampoos. Only those pet shampoos advertising 35:1 or greater dilution ratios are consistently more concentrated than human products. News flash: Most human shampoos can also be diluted. Pet and human shampoo manufacturers are all drawing from the same marketplace of chemical suppliers for their ingredients. In fact, some companies manufacture product lines for both pets and humans. There are no particular ingredients that are found in human products that are considered safe for people and acknowledged as unsafe for pets. The one thing I would say to keep in mind, whether shopping from the pet marketplace or human products aisle is that the more plant, protein, colour and fragrance, the greater the likelihood of an allergic reaction.
The Biggest Difference
Where there is a huge difference between pet and human shampoos is not what is in the bottle, but what is on the label. The labelling of human shampoos is guided by legislation that mandates that all ingredients must be disclosed in descending order of volume in the product and identified by their formal names. No such requirements exist for the labelling of pet products. Manufacturers are free to disclose or not disclose any or all ingredients.
A cloak of “trade secrecy” exists over pet products, with many major manufacturers refusing to reveal their main ingredients, and listing only additives or particular ingredients that have marketing value. Nor do ingredients in pet products need to be identified by formal (INCI – International Nomenclature of Cosmetic Ingredients) names. While a human shampoo would have to identify a primary surfactant as “Sodium Laureth Sulphate”, a pet shampoo could list the same ingredient as “mild coconut cleanser”.
This kind of ingredient description is a dodge ball tactic that allows pet product manufacturers to appear to have a list of ingredients while they continue to tell us very little about what is in the product. Because this is allowed, it makes these products look more benign and pet-friendly than the products that are labelled following the human cosmetics guidelines, and it makes it very difficult to compare pet products.