Fast fashion brands from ASOS to SHEIN have claimed their use of recycled polyester makes collections “sustainable” or “conscious”. But swapping out one synthetic for another doesn’t change the system’s underlying flaws. We look at why fast fashion’s increasing reliance on recycled polyester isn’t as green as it may seem.
Fast fashion’s plastic problem keeps growing
Polyester is everywhere. You might even be wearing the synthetic fibre right now without realising it, as it’s surprisingly versatile. Scan over any fast fashion website and you’ll find the material composition for everything from dresses and blazers to knit jumpers and loungewear to be primarily polyester.
Polyester is so pervasive that Textile Exchange reports it’s the most used fibre on the planet, accounting for 52% of the global fibre market in 2020. For fast fashion brands, using polyester makes sense: it’s cheap, strong, and durable. But that durability also presents a problem: polyester doesn’t biodegrade.
In more ways than one, fast fashion’s overproduction and reliance on virgin polyester is driving the waste crisis and the industry’s environmental scorecard to new lows. When it’s thrown out, polyester stays in the landfill for decades and potentially even centuries. And it’s made with non-renewable petroleum, a fossil fuel.
Due to these many negative impacts, organisations like Textile Exchange are pushing the industry to move away from its overuse of virgin polyester. In 2021, Textile Exchange and the UN Fashion Industry Charter for Climate Action launched the 2025 Recycled Polyester Challenge, with more than 130 companies signing on to accelerate a transition to polyester from recycled sources.
Even fast fashion brands have been publicising their commitment to using recycled polyester, with the fibre factoring heavily into almost every “conscious” and “sustainable” collection launched in recent years. Take evoluSHEIN, SHEIN’s “conscious” collection. Recycled polyester is the star material in almost every garment in the collection. A recent H&M campaign branded products like a faux fur jacket and a blazer dress made with recycled polyester as “circular”.
On the surface, that can make a cheap SHEIN dress seem like a better choice to the growing number of conscious-minded consumers. And many see the shift away from virgin polyester toward more recycled polyester as positive.
But when you look specifically at fast fashion brands, this one material switcheroo can seem like the only tangible change underpinning many of their sustainability claims. And that’s a big problem, according to a range of experts who worry fast fashion brands are greenwashing their use of recycled polyester without addressing the key drivers of their negative impacts: overproduction and waste.
Here’s what you need to know about fast fashion and recycled polyester, including how it’s made, its impacts, and the future of synthetics.
Recycled polyester is rarely made of recycled clothing
First, let’s clear up a common misconception: recycled polyester is rarely made from the fibres of recycled clothing.
The term “recycled” makes some consumers imagine that recycled polyester clothing means fibres from old polyester garments are recycled into new ones. But that’s rarely the case.
It’s quite challenging to recycle old clothing into new clothing. This is because garments are often a mix of different materials: there are blended fibres (commonly polyester blended with cotton), elastics, yarns, metal zips, plastic buttons, and so on.
This explains why so few of our clothes are actually recycled. In the US, just over 13% of clothes were actually recycled, according to 2018 data from the Environmental Protection Agency. Instead, unwanted clothes are more often discarded in environmentally harmful ways. More than 11m tonnes of clothing are incinerated or dumped in the US every year.
Instead, the recycled polyester you see advertised by fast fashion is almost always made from old plastic—coming from sources like water bottles instead of plastic fast fashion. In fact, Textile Exchange reports that in 2020 99% of recycled polyester was sourced from PET bottles—meanwhile “less than 0.5% of the global fibre market came from pre- and post-consumer recycled textiles”.
How recycled polyester clothing is really produced
Currently, taking plastics like single-use bottles and turning them into clothes is largely achieved through a mechanical recycling process. The items are melted down into pellets before being spun into new yarn. And this is what most brands use to make their recycled garments or accessories. Adidas, for example, works with Parley for the Oceans to turn marine plastic waste into sneakers.
This is a seemingly great solution for repurposing plastic waste, but it’s not so clearcut. Recycled polyester created through a mechanical process can’t be recycled again and again. This raises some concerns when fast fashion brands increasingly rely on the material. It also likely sustains demand for single-use PET bottles, not something we want to see. Recycled polyester is still often blended with virgin polyester, furthering the reliance on fossil fuels. And at the end of these garments’ lives, they’re still often destined for the landfill.
There’s no doubt that recycled materials have environmental benefits; they require fewer initial resources to make and cause fewer greenhouse gas emissions when compared with virgin materials.
Any brand shifting to some percentage of their production run to recycled synthetics is better than the alternative.
Cat Salvidge, a sector specialist for sustainable textiles at British nonprofit the Waste & Resources Action Programme (WRAP), says that even if recycled polyester is only used to make 20% of a garment, and the rest uses virgin synthetics like nylon or viscose, it’s still reducing the impact of that particular item of clothing—at least from the point of view of its carbon footprint.
“Replacing a proportion of the product with recycled fibres will still help to reduce a product’s impact when compared to using virgin materials. Switching 20% of the virgin polyester used by the industry to recycled polyester made using plastic bottles would reduce the carbon footprint by 4.5%,” she says. “And if we replaced all virgin polyester with recycled polyester, we could expect carbon footprint savings of more than 25%.”
Turning recyclable plastic bottles into non-recyclable clothing isn’t a sustainable solution for these brands.
But “better than the alternative” isn’t setting the bar very high for fast fashion brands, which are a primary driver of the industry’s environmental problems. Salvidge says the industry needs to go further when it comes to recycled materials. Turning recyclable plastic bottles into non-recyclable clothing isn’t a sustainable solution for these brands.
“We need to move towards our own closed-loop system of fibre-to-fibre recycling,” she says. This essentially means that every garment produced is made back into a new garment at the end of its life, reducing the need for virgin materials.
One proposed solution: textile-to-textile recycling
Textile-to-textile (or fibre-to-fibre) recycling means turning textile waste like old clothes into new textiles and new clothing. It’s a more circular paradigm.
But today, less than 1% of textile waste is textile-to-textile recycled, according to McKinsey.
There are a range of factors currently limiting textile-to-textile recycling, ranging from collection and sorting to processing challenges. For polyester, it can be a logistically difficult and labour intensive puzzle to solve.
A new wave of technologies described as chemical recycling aim to make textile-to-textile truly scalable—and resulting in better quality materials, as well.
UK-based Worn Again Technologies, for example, has been working on a scalable chemical recycling process that would turn hard-to-recycle blended garments into new virgin-like materials, keeping them in constant circulation. It’s still in the early phases of demonstrating whether its solution has broader potential. It’s building a textile recycling plant in Switzerland, which would demonstrate the company’s ability to create a scalable “closed-loop chemical recycling solution.”
But chemical recycling still raises some concerns of its own. Salvidge notes that chemical recycled synthetic fibres demand less energy than producing virgin synthetics, but more energy than conventional mechanical recycling. “The de-polymerisation and re-polymerisation processes typically happen at high temperatures” and thereby require a lot of energy to complete, she says.
There’s another obvious snag: the use of chemicals. If chemicals used in the recycling process aren’t correctly managed, they can be hazardous to both workers and the environment, explains Salvidge. To prove they’re recycling responsibly, brands can acquire third-party certifications. The Global Recycled Content Standard, for example, monitors waste management and prohibits the use of hazardous chemicals according to the ZDHC Manufacturing Restricted Substances List.
It’s not a straightforward issue. But for Salvidge, recycled fabrics always come out on top in comparison to virgin synthetics. And the biggest asset of chemical recycling is the end result. “The outputs [from chemical fibre-to-fibre recycling] are of the same quality as virgin materials, so 100% recycled content can be used,” she says. “With mechanical recycling, the fibres generally need to be blended with virgin materials to achieve the required performance quality from brands.”
Fast fashion is investing in textile-to-textile recycling
When chemical recycling is commercially accessible, fast fashion brands are already indicating they could adopt the practice. In fact, H&M is an investor in Worn Again Technologies.
In 2019, H&M’s investment manager for sustainable fashion said that the brand “looks forward to being an early adopter” of Worn Again’s solutions and will “integrate” the technology into its supply chain.
But moving toward innovative recycling methods still doesn’t do anything to address the root of fast fashion’s environmental impacts: overproduction.
For example, H&M reportedly produces around three billion items of clothing every year. If in some hypothetical future a brand like it could produce all of its clothing with fibre-to-fibre recycling methods, that still wouldn’t solve the environmental woes that come from overproducing clothing at that scale. Even with the ecological improvements that come with using recycled fibres, the recycling process still has its own environmental impacts, which only increase when ramped up to meet such a huge demand.
Another big snag: recycled polyester sheds microplastics
Recycled or not, synthetic fibres are a prime source of microplastics, which are tiny but environmentally-toxic particles of plastic.
“[Microplastics] are released from garments during all life stages, from production to use to washing to end of life,” explains biologist and ecotoxicologist Bethanie Carney Almroth, associate professor at the University of Gothenburg. She adds that these microplastics make their way into the waterways, causing damage to marine life. Research suggests they are toxic to fish, causing oxidative damage and neurotoxicity.
In the Arctic, studies have found that nearly three-quarters of microplastic pollution comes from polyester. These particles likely made their way there through manufacturing and laundry.
Fast fashion is highly problematic. This small effort to ‘recycle’ is not making a major impact.
In Almroth’s view, using a few more recycled materials is simply not enough to fix fashion’s environmental problems. “[Conventional] recycling only adds one ‘loop’ before the material becomes waste, so it is not truly sustainable or circular,” she says. “Fast fashion is highly problematic. This small effort to ‘recycle’ is not making a major impact.”
Almroth recently worked on a new report with the Stockholm Resilience Centre, and the findings showed that plastic and chemical waste is already out of control. With that in mind, she says there is only one way to reduce fashion’s impact on the planet: slowing down.
To put it simply, Almroth says: “we need to consume less.” And to accomplish that, fast fashion brands need to produce less. But right now, fast fashion’s overproduction only seems to be accelerating. SHEIN, for instance, relies heavily on synthetic materials, and every day it uploads thousands of new products to its website.
There’s no change without systems change
The bottom line: recycled polyester can’t solve fast fashion’s overproduction problem. Nothing can—aside from a systemic shift away from the take-make-waste model.
But innovations in this space should inspire some optimism. When combined with a slow down in production, fibre-to-fibre recycling could offer the industry a chance at reducing its impact. And if we’re going to deal with the polyester nightmare, a slow down is exactly what we need, experts tell me.
Fashion needs a fundamental system change, Salvidge tells me. “Brands and retailers need to address the issues of continued overproduction and overconsumption,” she says. WRAP, her company, is working with brands through its Textiles 2030 initiative to help them move towards circularity.
“Brands need to design for circularity, which means making sure their products are made using low impact materials and production processes, and are made to be long lasting and recyclable,” Salvidge adds.
And recycling is only one component of a truly circular business model.
“Brands also need to support their customers to care and repair for their clothing so that they can be kept in use for longer,” adds Salvidge. “[They need to] provide alternatives to buying new, such as resale and rental services, as well as provide accessible ways for customers to return clothing they no longer use, to be resold or recycled.” That’s only a start towards a truly circular economy.
Because, really, circularity isn’t just in the hands of fast fashion. It can start at home, with us, in our own wardrobes.
We, as consumers, have a role to play too, which starts with doing everything we can to stop piling more polyester into the landfill. We can buy second hand, outfit repeat, upcycle, personally resell what we already own, or swap with friends. And we can engage with our representatives to support the kind of regulation the industry needs. Because, really, circularity isn’t just in the hands of fast fashion. It can start at home, with us, in our own wardrobes. We can each be an enabler of change.