Episode 70: Is Recycled Polyester really a better, more sustainable material choice?




  • Definition of polyester and its prevalence in the textile industry
  • The proposed geological age of the "plasticene"
  • Challenges and concerns with recycled polyester claims
  • Addressing the 3 benefits often talked about when using recycled polyester
  • Comparison between mechanical and chemical recycling processes
  • A 2017 study on recycled polyester production


Belinda Humphrey - Website

Belinda Humphrey - Instagram

Belinda Humphrey - Email

Research tested the effects of microfibres from both polyester and cotton on the behaviour and growth of shrimp and fish


2017 study by the Swiss Federal office for the environment

Is polyester recycling a sustainable solution?

World’s first commercial poly-cotton recycling facility opens in Australia

Lab tests expose recycled polyester fraud

Is recycled polyester a sustainable choice?

Ecological footprint and water analysis of cotton, hemp and polyester


Hello and welcome to episode 70 of the Fashion Unearthed podcast. I hope everyone out there is well. And if you're new to the podcast, I sometimes talk about specific materials to align with the goal of conscious creation, and today is one of those episodes. If you do like the podcast, whether you are new or you've been around for a while, I would love it if you forwarded it to one friend who you think might be interested in sustainable and ethical fashion too. 

Today I wanted to talk about recycled polyester and specifically how is it sustainable and what are the benefits. It's a topic I've been collecting information on for a while, and because I predominantly work in casual wear denim, I'm often using plant-based fibre options. I've always felt a little bit uncomfortable using synthetics in my career and I don't work with any swim or activewear products now, but I do get asked a lot still about recycling polyester and I wanted to talk about it now as well because brands are rushing to respond to customers wanting sustainable materials. And all the big players implementing goals of replacing version polyester with recycled polyester by 2024, 2025, and 2030, and they're putting together detailed preferred materials lists. When this happens, it means that smaller brands follow it because that's what's happening in the industry and I guess it's a bit of peer pressure as well where brands don't wanna feel like they're behind. 

What is polyester? It's essentially a polymer made from fossil fuels such as petroleum and gas. Its technical name is polyethylene terephthalate. I always get these science names wrong. PET for short, which is what I'll be using. And since recycled polyester uses PET as the raw material, it often uses R-PET for recycled. And it probably comes as no surprise that it is everywhere. It's the largest percentage of fibre produced at 52% according to the Textile Exchange global fibre report for 2020.

Welcome to the plaster scene. If you are under the age of 70, you may have lived in the plasticene for your entire life. And this is a new geological age that some scientists have proposed to mark the basically near-universal spread of plastic around the earth. They say that since the 1950s we've been living in the age of plastics, which I think is just wild. But I wanna move on to the sustainability element next, which is the biggest bit. I think a lot of the general population would assume that plastic already exists, so it's better if we do something with it rather than create more, which is I think what we should be doing. But I wanted to address why it's not there at the moment. And there are holes in some of the common benefits that are often mentioned when talking about recycled polyester.

The first line that often gets thrown around is that it's helping to divert materials that would otherwise end up as waste, but brands should be wary of using these claims. To ensure their production volumes and consistency in quality for recycled polyester, companies need constant access to a large and stable pool of raw materials. And according to one article, it's still impossible to trace the origin of recycled polyester. You know, a few years back I even heard a rumour that factories were producing bottles to then be recycled, which sounds crazy, but to be honest, I wouldn't be surprised by much at this point. 

The second benefit that often gets mentioned, and I've seen this written on a sustainable fashion blog, is that garments made from recycled polyester can be recycled infinite times, which is completely untrue. Bottles can be recycled multiple times, but we are pulling resources out of this closed loop to put them into a garment that cannot be recycled any more times. It's simply not possible. I've worked in this industry for 20 years and believe me, if textile-to-textile recycling was available at scale, everyone would know about it. As a side note, wool has a long history of being sorted by colour and mechanically recycled and cotton is getting there, but not polyester. 

There is an innovative company in Queensland called BlockTexx that is moving into recycling cotton polyester fabric blends, but they're not using the separated waste in clothing in an apparel insider interview talking about their research into viable consistent feedstocks. They said that through our research in Australia and globally, we identified entire sectors of the market with limited end-of-life solutions because of security concerns and or unusable garments. These sectors had only two options burn it or bury it. The conclusion was to work with workwear and also textiles from laundries.

The third benefit that's often discussed is the energy demand that recycled polyester uses less energy. But let's briefly talk about the two ways polyester is recycled, the first being mechanical recycling where the chips are sorted and mechanically shredded. And this can be implemented with existing infrastructure and facilitate the use of waste plastic, which makes it appealing as a short-term sustainability target. But what then a fibre that has gone through this process can't go through it again because of strength and quality issues. The other limitation of mechanical recycling is that it retains its colour. Unless bleach is introduced, it can only be recycled into similar colours. And this is the process predominantly used in making recycled polyester at the moment. 

The other process is chemical recycling, which is a chemical process used to retrieve the raw material and it's emerging as a more promising strategy to enable material circularity as the products for chemical recycling can be the same inputs as the original product, meaning that it has the potential to enable that infinite loop. But this is nowhere near being available at a viable commercial scale. It's very niche and it's not technologically or economically mature. 

Going back to the benefit of having a lower environmental impact, I found this study quoted a lot. It's a 2017 study by the Swiss Federal office for the environment. They found that recycled polyester production requires 59% less energy compared to virgin polyester. The report acknowledges that due to the limited availability of published and open source data on recycled fibres, they relied a lot on the data in information from the textile exchange, but it gives no detail as to what stage of the manufacturing process is being assessed or what data from Virgin polyester manufacturing it's being compared to. Essentially there's just no reference to how they got to that percentage. And I've seen this stat mentioned on other sustainable fashion blogs, shopping guides, and even mill websites with no link back to exactly how they've come up with that percentage.

In terms of water, that same study states that accurate water footprint data for polyester fibre production does not currently exist, but they say the water footprint for both recycled and virgin polyester is low, so there's not much difference. Side note, I often found water reduction as one of the benefits on other fashion blogs with no mention of how including one that claimed it reduced the water by 90% with no reference. 

Moving on to the CO2 emissions, they say that recycled polyesters reduce emissions by 32% compared to Virgin polyesters. For this stat, they quote WRAP 2017 and the footprint calculator used for the sustainable clothing action plan and they give the web address, but I can't find where exactly they pulled this from on the link, so I can't comment on how they compared the two and what was included. However, as the plot thickens a 2022 study in China claims that recycled polyester production has 10 times the CO2 emission of virgin due to a series of energy-intensive procedures such as crushing high temperature cleaning and drying of the chips, which are involved in the spinning stage from waste polyester, which is a huge swing in the other direction.

Welcome to the wild world of lifecycle assessments, otherwise known as LCAs, and they're a whole other podcast and tricky to simplify, but I have it on my list of things to talk about at some stage. A lot of data that you get is actually from mills trying to sell you their fabric or bloggers using these marketing stats. The original data is not openly available, and that's an industry-wide issue. I do want to bring up another study though this time from Brazil in 2021 and I've put a link to it in the show notes. But they compared the environmental impacts of cradle-to-gate for both bottle-to-bottle and bottle-to-fibre recycling. And in five of the seven categories evaluated bottle-to-fibre had a greater environmental potential impact. However, both showed a lower impact than virgin PET. So this is promising.

It does seem to show a reduced environmental impact if you are using recycled polyesters over virgin. That is of course if you're getting recycled polyester in your garments. In a 2021 study, randomly selected garments from a range of high-street fashion brands were tested in a European lab and they were found to contain zero or very little actual recycled polyester where the researchers did find recycled polyester. It was much less than what was written on the tag. And it's probably no surprise that the findings confirm long-held rumours within the industry that virgin polyester is being substituted for its recycled counterpart in fashion supply chains and on a big scale. I think maybe you can see why I've avoided tackling this in a podcast. At the end of the day, it's still plastic and along with still shedding both when you're wearing it and washing it, some studies have shown that recycled polyester sheds more microfibers. It can be contaminated with other plastics that contain endocrine disruptors, and chemicals that mimic human hormones and have been linked to all sorts of illnesses such as thyroid issues, cancers, infertility and developmental issues in children.

Along with that polyester microfibers have also been shown to affect growth in microorganisms that have ingested it. And when we come to the effect on humans, we've seen evidence of microplastics in the placentas of human blood and another 2015 study found them in 67% of all seafood at fish markets in California. And we don’t know what kind of long-term impact this is having from within us, but you can assume it's not meant to be there, so it's probably not gonna be good. Add to that, whatever polyester you use, if you blend it, it's even less likely to even be downcycled into another product area within the industry. The holy grail being talked about is having a highly evolved system for waste collection and sorting and the creation of chemically recycled polyester that doesn't shed microfibers, but this technology is at least several years away. In light of all this, I would proceed with caution and assume there is no such thing as sustainable polyester.

The advice from scientists remains to reduce the amount of polyester being used. I would add to that, if you can't source the actual energy data from the recycled polyester you're using, remember that the manufacturing location and energy source have a huge impact on greenhouse gases, don't wing it. And if you do get the data, be very specific about what recycling methods are used, what comparisons are being used, as well as actual links to the data, our reliance on polyester needs to be reduced. The ability to recycle it again and again isn't there at scale. So taking plastics from bottles and putting them into garments that can't be recycled is a very short-term problem shift. If we zoom out a little bit from comparing virgin and recycle polyesters' energy demands and compare both of these to the energy required for natural fibres, both require significantly more energy than hemp wool and both organic and regular cotton.

According to a 2010 report from the Stockholm Environment Institute, it's worth mentioning that that particular study used a scenario where polyester was manufactured in Europe and America, whereas the majority of polyesters are produced in China and India. So this could be even greater if you were to use those countries as a base instead. And this study is quite old now, but I thought it was worth mentioning to maybe think about zooming out a bit and consider any perceived benefits in a greater context of material choices, especially if you're using polyester in areas where there's another option. We can't keep using plastic as wastefully as we have been. It needs a proper management system after its use that is circular. We can't put the genie back in the bottle, so we have to improve this quickly. And if it does happen, there's an opportunity to have less pollution and a more efficient material sector.

If you're still here and listening and have made it through quite a heavy podcast episode. Thank you. But I hope that it's given you a bit of clarity around recycled and how it is or isn't more sustainable than virgin polyester. And a reminder that if you did like the episode, I would love it if you shared it with a friend who would also be interested to know more about sustainable and ethical fashion. And as always, you'll find the show notes and all the links on the website, Belindahumphrey.com in the podcast section. Thanks so much for listening. See you next time. 

Thanks for listening to the Fashion Unearthed podcast. If you want to get in touch head over to belindahumphrey.com or you can find me on Instagram @belindahumphrey_

Disclaimer: Whilst every effort is made to ensure that information is accurate at the time of recording, much like the fashion industry itself, this information may change.


More Posts