There is an urban myth circulating through the pet grooming industry that mainstream pet shampoos may contain a toxic anti-freeze ingredient. In order to dispel this myth, it is necessary to distinguish between ethylene glycol and propylene glycol.
Ethylene Glycol (EG) is a moderately toxic chemical that is used primarily as an antifreeze and engine coolant and in the manufacture of PET plastic. When ingested orally, it causes kidney damage and is often fatal, especially to small animals and children. Ethylene glycol is not used as a cosmetic ingredient.
Propylene Glycol (PG) is an organic alcohol that is not toxic and is GRAS (Generally Regarded as Safe) by the FDA, and is approved for use as a food additive. It has been extensively studied. Dermal application shows no irritation or allergic response. It is not carcinogenic and does not cause genetic mutation. Propylene Glycol is one of the most widely used cosmetic ingredients. It is hygroscopic (attracts water from air) and is used as a humectant, moisturizer and skin conditioner. It also keeps products from drying out.
Other features of PG are that it is miscible in water and does not react with other ingredients (plays well with others). It is also used to stabilize products. These properties make it a popular ingredient with cosmetics formulators.
Propylene Glycol and Ethylene Glycol share the property of lowering the freezing point of water. Because of its low toxicity, PG has found use in non-toxic anti-freeze applications. The answer to the question, “Is there anti-freeze in my pet shampoo?” is “It could be.” But you might as well ask, “Is there a moisturizer in my anti-freeze?” The fact that a substance has multiple uses in multiple industries does not render it unsafe or undesirable for cosmetics.
Unfortunately, one of the marketing tactics in the highly competitive pet shampoo marketplace is to make consumers uncomfortable with mainstream products by targeting ingredients and fueling misconceptions and rumors about that ingredient. Propylene Glycol has been the target of this tactic. Nearly every pet lover is aware that anti-freeze is sure death if ingested in sufficient quantities. By associating Propylene Glycol with anti-freeze, the fear mongers can then proudly proclaim, “We use no anti-freeze ingredient in our shampoo.” That claim immediately raises the suspicion that OTHER manufacturers ARE using anti-freeze in their shampoos. To make matters worse, there are no ingredient lists available for many pet grooming products, so the groomer can’t even check their products for specific items. This lack of transparency creates a fertile field for scare tactics to flourish.
Allow me to repeat: the toxic ingredient that makes traditional engine anti-freeze deadly is Ethylene Glycol. There is no Ethylene Glycol in pet shampoos. Period. The cosmetic ingredient, Propylene Glycol, has a myriad of applications, including use in NON-TOXIC anti-freeze preparations. Propylene Glycol has been extensively studied and all studies have been reviewed by the CIR (Cosmetics Ingredient Review) Expert Panel and determined to be safe as used in cosmetics, including shampoos. The National Toxicology Program (NTP) has also ruled that Propylene Glycol is safe.
REFERENCES & FURTHER READING:
Ethylene glycol monomethyl ether and propylene glycol monomethyl ether: metabolism, disposition, and subchronic inhalation toxicity studies.
www.cosmeticsinfo.org - search under Propylene Glycol