PFAS in Period Underwear
June 14, 2022

PFAS in Period Underwear

A few days ago we posted a TikTok about per- and polyfluoroalkyl substances (PFAS) in period underwear that got over a million views. We received a lot of comments and wanted to take the time to address your top questions about PFAS chemicals.

There’s been a ton of discussion around the safety of period underwear recently with class action lawsuits around some of the biggest names in the business. Since by its very nature, period underwear spends significant amounts of time rubbing against very sensitive skin, it’s important that it’s made from safe materials. Yet, toxic “forever chemicals” like PFAS are turning up in the products of companies you’ve trusted with your most delicate needs. 

You deserve to know what goes into your personal care products. In this article, we’ll look at what exactly PFAS are, how we’re exposed to them, their concerns, how to make informed choices when it comes to period underwear, and which period underwear we love at Oliver.

What are PFAS?

PFAS stands for per- and polyfluoroalkyl substances. They’re a group of man-made chemicals that includes Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA). They’re commonly known as “forever chemicals” because they never break down (not in our lifetime at least). Because of this, they can build up in our bodies and interfere with important functions like our hormonal system. 

Yes, PFAS are endocrine disrupting chemicals (EDCs) and have been linked to several health concerns.

Human Health Concerns of PFAS

According to the US Environmental Protection Agency, based on peer-reviewed scientific studies, the most common health effects of exposure to certain levels of PFAS are:

  • Endocrine/hormone disruption 
  • Developmental effects or delays in children 
  • Reproductive toxicity leading to low birth weight, thyroid disruption, harm to sperm and the male reproductive system, and pregnancy-induced hypertension
  • Increased risk of certain cancers such as testicular, prostate, breast, ovarian, liver and kidney cancers
  • Decreased immune system function 
  • Increased levels of cholesterol and/or risk of obesity

Where are PFAS found? 

PFAS, like most endocrine disrupting chemicals, can be found almost everywhere.

They’re commonly used to make products water and stain repellent. 

In your home, you’re most likely to find them in your food take-out containers, non-stick pans, mattress protector, shower curtain, umbrella, table cloth, even your raincoat and outdoor gear. In fact, REI is also facing a lawsuit for PFAS in their clothing. 

How did PFAS End Up in My Underwear?

PFAS are added to period underwear for their moisture-wicking, stain-resistant abilities. Name a better use case for these chemicals than period underwear! But not all period underwear contains PFAS. Natural materials exist that are absorbent and leakproof, keep reading for our top pick for period underwear. 

PFAS in Cosmetics 

PFAS in period underwear represent a much larger issue of endocrine disrupting chemicals in personal care items. One that we’re only just starting to illuminate.

PFAS have been found in moisturizers, foundation, eyeliner, mascara, shaving cream, dental floss and more. They’re added to cosmetics to make them waterproof or “long lasting”, change the product texture, make products have a shiny finish, or as “anti-frizz” ingredients in hair styling products.

A 2021 study published in the journal of Environmental Science and Technology Letters tested cosmetics from the US and Canada and found PFAS in more than half of the 231 cosmetics tested. Most of these products did not list PFAS on their label. 

PFAS can also get into cosmetics unintentionally through raw materials or the manufacturing process. Or, through leaching from storage containers. 

How to Spot PFAS on a Cosmetic Label

According to the US FDA, “some common PFAS used as ingredients in cosmetics include PTFE (polytetrafluoroethylene), perfluorooctyl triethoxysilane, perfluorononyl dimethicone, perfluorodecalin, and perfluorohexane”. 

The easiest way to spot PFAS on a label is to look for “fluoro” in the ingredient name.

Are PFAS in Cosmetics Safe?

Of course, there is much more research to be done on exposure to PFAS through cosmetic products. Absorption through the skin is not a major route of exposure, but applying these chemicals to the eyes and lips can greatly increase exposure. PFAS are found in products that can be used starting from a very young age. 

While the dangers of PFAS through skin absorption aren’t as great as when they’re ingested, PFAS in period underwear are still a major health concern as the underwear is rubbing directly on the sensitive, thin skin of the vagina (which also leads into the body, in case anyone forgot).

Also, the interaction of PFAS with the mixture of other endocrine disrupting chemicals in the body is not well understood. Because of this experts have advised us to reduce exposure to all endocrine disrupting chemicals.

The Problem with Testing Products for Endocrine Disrupting Chemicals 

As we’ve stated before, endocrine disrupting chemicals challenge the way cosmetics and other personal care products are regulated. Why? Because EDCs don’t follow the assumption that “the dose makes the poison”, which the entire cosmetics industry is regulated on. 

EDCs can have effects at low doses that are not predicted at higher doses, called “low-dose effects”. These low doses are almost never tested. In other words we don’t really understand what the impacts of these chemicals are because we’re not testing them properly. 

We’re excited to see the huge steps being taken in the EU with the EU Green Deal, which takes into account the challenges of safety testing around EDCs and will re-evaluate the safety of cosmetic ingredients with endocrine disrupting properties. 

How to Choose Period Underwear without PFAS

 Always choose a brand that has done third party testing and is transparent in disclosing their results. Organizations like the Sierra Club and Mamavaiton have done independent testing on PFAS for several brands of period underwear. We encourage you to check out their results! 

Look for companies that have their products routinely tested for PFAS. We admire companies like Aisle for regularly having their products tested by SGS - a leading testing and inspection company.

At Oliver, we personally use and love Aisle products because there have been no detectable levels of PFAS found in third party or SGS testing.


There’s a huge lack of consumer protection laws for period products. It’s up to us to make choices and it’s really hard to keep up with this ever changing world. 

We want you to have the knowledge you need to make informed decisions. Oliver is dedicated to creating a hormonally happy future by making products that are free of all known or suspected endocrine disrupting chemicals. So you can have confidence that the products you’re putting on your skin aren't messing with your hormones.