When it comes to skin care and makeup, many of us probably have a list of ingredients we would never put on our faces — some lists longer than others. But one ingredient with some heavily skewed opinions is polyaminopropyl biguanide, also known as polyhexamethylene biguanide or PHMB. But what is PHMB and is it bad for you? The ingredient is used in some pretty popular products in the USA but is actually banned from use in cosmetics in other countries. So what gives? To find out a little more about this controversial ingredient and whether you should avoid it, I emailed with a few experts.
Rachel Winard, founder of Soapwalla; Holly McWhorter, co-founder of PLANT Apothecary; and Dr. Clarissa Shetler and Christine Falsetti, PhD, founders of C2 California Clean, all let me in on what PHMB is commonly used for along with some other useful information about the ingredient so you can make a more educated decision whether to use beauty products containing it. According to Winard, PHMB is a "synthetic polymer that is used as a broad-spectrum preservative and antimicrobial agent in skin care." Drs. Shetler and Falsetti add that it can be found in many personal-care products "including skin care, cosmetics, eye-care solutions, wound care, and surgery care."
However, Drs. Shetler and Falsetti say that even though PHMB has proven antibacterial properties, it has also been shown to be harmful. McWhorter explains: "There's evidence based on results of studies on humans and animals that [PHMB] is carcinogenic (causing cancer), mutagenic (causing gene mutation), and toxic. It's suspected primarily of affecting the reproductive system." Yikes.
The Scientific Committee on Consumer Safety (SCCS) has also concluded that PHMB is not safe when used as a preservative in a concentration higher than 0.3-percent in cosmetic products, say Drs. Shetler and Falsetti. And according to McWhorter, in the EU, PHMB was banned in personal-care products after being labeled a Category 2 Carcinogenic Agent in 2015.
Not everyone seems to agree on the dangers of this preservative though. PHMB use in personal-care products is legal in the USA, and according to Drs. Shetler and Falsetti, "There are still many debates on the safety profile of the ingredient and some companies will still insist the ingredient is safe." So even though you can still find this ingredient on the shelves in US stores, if you're worried about using products with PHMB, check out this list of products known to include the ingredient, and always read product labels to be sure whether PHMB (although it may also be listed as polyaminopropyl biguanide or polyhexamethylene biguanide) is included.