Last week, I shared a recipe on a holistic grooming group. It was an essential oil blend in water that works well to repel mosquitoes, flies, and other pests. I use Polysorbate 20 to dissolve the essential oils in the water. I thought it would be an easy share, post the recipe and wait for the “thank you’s.” Silly me. Instead of gratitude, I got questions, a vivid reminder of why pet product manufacturers are reluctant to share the specifics about ingredients. Armed with information from quick searches on the Internet, some groomers have now become Ingredient Police. YIKES, I have created a monster. My years of encouraging groomers to ask for ingredient information has now turned around and bit me in the butt. OUCH!
One of the ingredient questions was about my use of Polysorbate 20. “I just read Polysorbate 20 is a carcinogen. Due to the ethylene oxide. Are there any substitutes?” The poster did not say where she read this, but here is what I have read with my sources noted.
FROM WIKIPEDIA:
Polysorbate 20 (common commercial brand names include Alkest TW 20 and Tween 20) is a polysorbate surfactant whose stability and relative non-toxicity allows it to be used as a detergent and emulsifier in a number of domestic, scientific, and pharmacological applications. It is a polyoxyethylene derivative of sorbitan monolaurate, and is distinguished from the other members in the polysorbate range by the length of the polyoxyethylene chain and the fatty acid ester moiety.1
The polysorbates have many applications: they are used widely in cosmetics to emulsify (mix) various oil substances in water-based products. They are used in ophthalmological products to help spread the active ingredients. Polysorbates are approved food additives and they appear in many foods such as whipped toppings, ice cream, cake and cake mixes as well as breath mints and mouthwash, just to name a few.
Polysorbate 20 and Polysorbate 80 are the polysorbates that most often show up in pet grooming products. Polysorbate 20 is the emulsifier of choice of aromatherapists and cosmetic formulators for mixing essential oils in water. 2,3 Polysorbate 80 is used to mix heavier oils, such as sunflower oil, olive oil, argan oil, etc. 3 Without these emulsifiers the oils would not mix uniformly throughout the product, but would separate or not be homogenous.
FROM COSMETICS INFO.ORG4
Polysorbate 20 and the other Polysorbate ingredients (Polysorbate 21, Polysorbate 40, Polysorbate 60, Polysorbate 61, Polysorbate 65, Polysorbate 65, Polysorbate 80, Polysorbate 81, Polysorbate 85) are a series of general-purpose hydrophilic, nonionic surfactants. The Polysorbates are used in a variety of products including skin fresheners, skin care products, skin cleansing products, makeup bases and foundations, shampoos, permanent waves and fragrance powders.
Why are they used in cosmetics and personal care products?
The Polysorbate ingredients help other ingredients to dissolve in a solvent in which they would not normally dissolve. They also help to form emulsions by reducing the surface tension of the substances to be emulsified. In shampoos and conditioners, Polysorbate 20 and Polysorbate 80 are often used to mix fragrance oils, natural or synthetic, into the water-based products. 4
Scientific Facts:
Polysorbates are surfactants that are produced by reacting the polyol, sorbitol, with ethylene oxide. The number in the name of the Polysorbate indicates the average number of moles of ethylene oxide that has been reacted per mole of sorbitol. The polyoxyethylenated sorbitan is then reacted with fatty acids obtained from vegetable fats and oils such as lauric acid, palmitic acid, stearic acid and oleic acid. Polysorbates function to disperse oil in water as opposed to water in oil.2
THE ARGUMENT AGAINST POLYSORBATE 20
The primary criticism of Polysorbate 20 comes from its manufacture. It is made with reaction of sorbitol with ethylene oxide. This process of ethoxylation can result in the creation of trace amounts of a by-product, 1,4-dioxane. The key words here are “trace amounts”, which translates into an extremely small potential presence. Dioxane was identified as a carcinogen after a 2-year study of rats and mice that were constantly fed the substance developed liver and mouth cancers. There is no doubt that in significant amounts dioxane is dangerous. The amounts occurring during cosmetic manufacture, however, are nowhere near these significant amounts. Moreover, chemical manufacturers are aware of a vacuum stripping process by which the trace amounts of dioxane can be removed from the ingredient or end-product, further minimizing any amount of dioxane being present in the products we use.
Here is the official statement of the FDA regarding 1.4-Dioxane in cosmetics:
FDA has been monitoring this issue since the late 1970s. We periodically monitor the levels of 1,4-dioxane in cosmetic products, and have observed that the changes made in the manufacturing process have resulted in a significant decline in the levels of this contaminant. (Roderick E. Black, Fred J. Hurley and Donald C. Havery, "Occurrence of 1,4-Dioxane in Cosmetic Raw Materials and Finished Cosmetic Products," Journal of AOAC International, 84 (3), 2001, pp. 666-667)
FDA has not established or recommended a specific limit on the level of 1,4-dioxane in cosmetics. We have provided guidance to manufacturers alerting them to the health concerns and how to minimize 1,4-dioxane by means of a process called "vacuum stripping" at the end of the polymerization process.
If FDA were to determine that a health hazard exists, it would advise the industry and the public, and would consider its legal options for protecting the health and welfare of consumers.5
Who are we to believe? While I have a certain rational skepticism concerning the effectiveness of the FDA, I choose to believe in science rather than those voices that have a vested interest in stirring up our fear of cancer related to everyday products and ingredients. In the U.S., we have the Cosmetics Ingredient Review (CIR) Expert Panel, an appointed group of scientists and experts that reviews all existing data about ingredients and makes recommendations regarding safety and use. In regards to Polysorbate 20, the CIR Expert Panel evaluated the scientific data and concluded that Polysorbate 20, 21, 40, 60, 61, 65, 80, 81 and 85 were safe as cosmetic ingredients. “Evaluated the scientific data” - the CIR not only reviews all of the published studies on an ingredient, but evaluates the reliability and applicability of each study. A study that has flaws in the design, such as inadequate numbers, poor controls, inconsistencies in application, etc., does not get the same weight in a decision as would a well-designed and controlled study.
The notion that Polysorbate 20 causes cancer is based on the studies of 1.4 dioxane, not on any studies of Polysorbate 20. To apply this cancer hazard to all ingredients that are manufactured by means ethoxylation with ethylene oxide or where 1.4 dioxane is a trace by-product is fallacious. It is an unsound argument and it is deceptive and misleading.
REFERENCES:
- Polysorbate 20 – Wikipedia http://en.wikipedia.org/wiki/Polysorbate_20
- https://www.naturesgift.com/product/polysorbate-20/
- Point of Interest: Polysorbate 20 vs. Polysorbate 80, Susan Barclay, http://swiftcraftymonkey.blogspot.com/2010/05/question-polysorbate-20-vs-polysorbate.html
- Cosmetics Info. Org http://cosmeticsinfo.org/ingredient/polysorbate-ingredients
5. FDA statement re 1.4dioxane contamination in cosmetics.http://www.fda.gov/cosmetics/productsingredients/potentialcontaminants/ucm101566.htm
OTHER REFERENCES AND READINGS
1. http://www.naturalsourcing.com/msds/MSDS_Polysorbate_20.pdf
2. CRC Handbook of Food, Drug, and Cosmetic Excipients
By Susan C. Smolinske, CRC Press, 1992,
FOOD USES:Polysorbates 20, 60, and 80 are approved as direct food additives as synthetic flavorings.
Monkeys fed Polysorbate 20 for 20 months at 1g/day showed no histological abnormalities. (Histological examination is the microscopic testing of body tissues. Poor monkeys!)