"Is Polyester Clothing Made From Recycled Plastic Bottles Toxic?" is the headline of an article written by Ruth Alden Wicker, published on Feb 7, 2022.

As quoted below, Ruth set out to investigate any truth to the rumor that wearing material made from recycled plastic bottles is harmful for human health, as theorized by wellness influencers based on the warnings against reusing plastic water bottles.

Due to studies that found under certain conditions harmful endocrine-disrupting substances like BPA or phthalates can leach out of plastic water bottles and interfere with thyroid function and hormones, the theory is that this could also occur while wearing material made from plastic water bottles.

What are those conditions? 

"The study on Chinese water bottles indicated that the BPA release at four weeks in 158-degree heat was below EPA standards"

Explains Ruth's article, linking to a National Geographic article with more research findings and quoting Dr. Martin Mulvihill on the topic "I am not overly concerned about it impacting human health.”

"It" being wearing material derived from plastic bottles.

Who is Dr. Martin Mulvihill?

"A trained chemist, researcher, and senior advisor and board member at the Berkeley Center for Green Chemistry, which he helped create and where he served as the founding initial Executive Director from 2010 to 2015. He’s now the co-founder and partner at Safer Made, a mission-driven venture capital fund that invests in companies and technologies that reduce human exposure to harmful chemicals. In other words, he’s an expert." writes Ruth.

To put this into perspective, our body's pain threshold for heat is 106-108 degrees and first degree burns occur at 118 degrees followed by second and third degree burns at 131 and 162 degrees respectively. That is to say, after mere moments of wearing polyester material in these conditions we'd have bigger problems to worry about than low level toxin release.

In fact, many of our materials have been tested and offer UPF 50+ protection to help protect from a very common type of first degree burn - sunburns! 

Still, as the debate on whether or not any level of exposure to these toxins is safe continues here, our take is this:

Based on the evidence, as athletes who sweaty experiences are greatly enhanced by the performance benefits of polyester, we're not concerned and will continue to wear recycled polyester as a much more sustainable alternative to virgin polyester and nylon. The sweat wicking, quick-drying, durability and shape retaining characteristics of synthetics are essential to our activities of choice, and I can tell you right now, cotton leggings on a week-long fast-packing adventure during rainy season would be a terrible idea (and a real safety concern).

However, if you are worried about wearing polyester and if the performance benefits of polyester are of no personal benefit to your activities of choice, then it may not be the best material choice for you for a couple of reasons:

1. Stress alone can create hormonal imbalances harmful to our health, so if you're worried about wearing it, it's best to go with your gut feeling and wear what feels best for you.
2. While the higher cost of recycled polyester is a worthy investment for athletes after it's technical features, if you're not planning to run everyday, hike up mountains or stretch your limbs so far that shape retention is a requirement, then the higher cost isn't necessary. 

We agree organic cotton is a more affordable, comfortable, breathable, and sustainable selection ideal for non-sweaty, leisure activities.

As an activewear brand, we're primarily focused on designing sustainable athletic tights for running, hiking, working out and yoga. However, behind the scenes we've sourced an organic cotton and wood fiber blend material suitable for yoga leggings. We plan to develop this style to wear for the leisurely activities we do as part of our recovery in between our more sweaty pursuits and wild adventures!

Alas, as sublimation printing only works on polyester, the cotton blend leggings will be unable to feature our unique wilderness prints and will be solid colors.

On to the next question at the forefront of inquisitive minds...

What about laundering?

The hot water setting on washing machines is about 130 degrees and thus below the heat-threshold considered to be safe for storing plastic water bottles for long periods of time. Also, as per the care labels, it's best to wash activewear materials in cold water.

Should we be worried about 'Phthalates'?

Polyester, aka PET or rPET (recycled) stands for polyethylene terephthalate:

"Phthalate" is part of a group of chemicals known or suspected to be endocrine disruptors, however "terephthalates are not suspected to be endocrine disruptors in the same way that ortho-phthalates are,” Dr. Mulvihill said. They’re not one of the phthalates banned in the European Union, for example. And he’s seen no evidence that any phthalates leach into the water inside PET water bottles, much less leach out of PET polyester clothing wearing it." 

And other contaminates?

Dr. Mulvihill does go on to explain that contaminates can have endocrine disruptors. 

“That said, contamination severely impacts the quality of fiber, so a lot of time and effort goes to removing any non-PET contamination. The amount of contamination probably isn’t zero, but I haven’t seen any data to indicate it is a serious concern…I think that this could be an example of how the public messaging around plastic = bad when it comes to food is having an unintended consequence,” Mulvihill concluded.

Is there anything we should be concerned about?

There is something worthy of our concern - fabric finishes containing harmful chemicals!

These are treatments applied to the surface of materials to meet consumer requests for garments that won't wrinkle or smell over time.

While the chemicals in polyester would only leach out under extreme heat conditions, the likes of which we wouldn't experience while wearing it, the chemicals found in many fabric finishes are "always off-gassing, sloughing off, or mixing with your sweat" writes Ruth.

For example, an organic cotton blouse might be surface treated with formaldehyde to prevent wrinkles, whereas polyester knit materials are wrinkle resistant by construction.

One claim to pay attention to, as cheap versions used by fast-fashion brands often contain BPA's, are garments with anti-bacterial or anti-odor finishes. If you see this claim, you'll want to ensure the finish is all-natural and EPA certified to avoid the likelihood of harmful chemicals seeping into your skin while you sweat. Our fabrics have an all-natural, EPA certified anti-bacterial finish called Chitosante.

Our commitment to transparency:

Part of our mission at Bewildher is to connect active women to the processes behind their activewear, and thus we are ever researching the latest news in sustainable activewear textiles technology and will share our findings transparently with our customers. Keep checking this space, our blog, for updates as we delve deeper into these topics!

Have a question or concern? Please feel welcome to contact us via the green button bottom right of your screen. We love chatting, researching and learning about textile advancements that are important to our health and wellness journey! 

Header Photo by LiiPhoto