What is Propylene Glycol?
Propylene glycol is a delivery agent that can be derived from glycerin. Propylene glycol helps improve the skin repair functions of our creams. Propylene glycol helps our creams and lotions penetrate the skin and carry copper peptides to the hair follicle, where the remodeling process can begin. Propylene glycol is commonly used in a plethora of personal care products, as well as foods like ice cream.
Is Propylene Glycol Safe?
Propylene glycol is considered a safe ingredient not just for cosmetic products, but also for ingested products like food and pharmaceuticals. It is on the US Food and Drug Administration's list of ingredients which are Generally Recognized As Safe (GRAS) and is recognized by the World Health Organization as safe for use.
The “Controversy” Around Propylene Glycol
We receive many phone calls from our clients who are alarmed by websites that claim propylene glycol is a controversial and dangerous ingredient.
Propylene Glycol vs. Ethylene Glycol
Some claims mistakenly equate propylene glycol with the different and dangerous chemical ethylene glycol. When absorbed into the skin, propylene glycol is metabolized into lactic acid, which occurs naturally as muscles are exercised, while ethylene glycol is metabolized into oxalic acid, which is toxic.
Some websites claims made that propylene glycol is an inappropriate ingredient for cosmetics and foods because it can also be used in products (such as antifreeze) which one would not want to consume. Such observations are misleading. It is ethylene glycol, for example, which is a more common ingredient in antifreeze and which is, in fact, highly toxic. The American Society for the Prevention of Cruelty to Animals (ASPCA) actually recommends the use of propylene glycol-based antifreeze because it is safer than ethylene glycol should pets accidentally ingest it. Simply because propylene glycol has many different applications does not make all the products which contain it the same.
Propylene Glycol's Safety Sheet
Another effort to demonize propylene glycol focuses on what is allegedly disclosed by the ingredient's Material Safety Data Sheet (MSDS). MSDS information can be found on the Internet, but rarely are viewers given any background or context on how to read one. An MSDS is a safety disclosure which instructs manufacturers and shippers on proper procedures for handling ingredients, for treating accidental exposure, and for cleaning up spills. Even the purest ingredients like essential oils have an MSDS. There is usually no single MSDS for an ingredient, but one for each different form or concentration offered by each ingredient supplier. For ingredients which could be shipped in a liquid or solid form, the MSDS for each form may differ significantly and each has little bearing on what properties the ingredient will have when combined with other ingredients into a formulation.
The MSDS for the propylene glycol we use contains no indications of carcinogenicity or chronic exposure effects. The concentrated form of the ingredient can, however, cause temporary reddening, stinging or swelling when it comes in contact with the eyes or skin. This indication does not mean that a product formulated with the ingredient will have irritating properties. The minuscule amount of propylene glycol used in our products will not cause irritation.
Some “natural” cosmetic companies claim that propylene glycol is a carcinogen wrongly approved by the FDA. The FDA, WHO and major scientific bodies have found their claims are completely unfounded. Propylene glycol's extensive safety studies have shown it to be completely safe when used properly. The Department of Health and Human Services states “studies have not shown these chemicals [propylene or the other glycols] as used in cosmetics to be carcinogens”.
We feel confident that research and a long history of safe usage have shown propylene glycol to be a safe and appropriate ingredient in skin and hair creams such as ours.
Rare special cases...
Post menopausal women who require the use of an estrogen cream may notice that brand name creams made with propylene glycol often create extreme, uncomfortable burning along the vulva and perianal area. In these cases, women can request that a local compounding pharmacy make a "propylene glycol free" cream which is much more tolerable.
Women with vulvodynia and interstitial cystitis may be especially sensitive to propylene glycol. Women struggling with yeast infections may also notice that some brand name creams can cause intense burning.