Is Buying Recycled Polyester Actually Good for the Planet?

Walk down any UK High Street and you’re met with a sea of green labels. “Conscious Choice,” “Sustainable Style,” “Made With Recycled Materials.” The message is clear: you can buy new clothes and save the planet. Recycled polyester, often abbreviated as rPET, is the poster child for this movement. The narrative is simple and appealing: we’re taking single-use plastic bottles, a symbol of environmental waste, and transforming them into soft, wearable garments. It feels like a win-win, a perfect circle of consumption without consequence.

This narrative, however, conveniently omits critical engineering realities. As a textile engineer specialising in circular systems, I argue that the widespread use of rPET in fashion is less an environmental solution and more a sophisticated greenwashing mechanism. It addresses the symptom—plastic bottle waste—while ignoring the disease: a linear, disposable fashion model. The process isn’t truly recycling; it’s downcycling. It’s a one-time diversion that takes a high-grade, food-safe plastic and turns it into a low-grade textile fibre with a limited future and a polluting present.

The core of the issue lies in the material science and the systems that surround it. The strength of the plastic polymer degrades with each reprocessing cycle, the fibres shed polluting microplastics with every wash, and the final garment has almost no viable pathway back into a circular system. It’s a dead end, merely delaying the plastic’s inevitable journey to landfill or incineration.

This article will deconstruct the “recycled polyester” claim from an engineering perspective. We will analyse the hidden environmental costs, the technical limitations of the material, and the commercial incentives that drive its use by fast-fashion giants. The goal is not to dismiss all efforts but to arm you, the conscious consumer, with the critical facts needed to see past the marketing and evaluate what “good for the planet” truly means.

To navigate this complex topic, we will break down the key issues, from the microscopic pollution in your washing machine to the systemic failures in textile waste management. The following sections provide a structured analysis to help you understand the full lifecycle of a recycled garment.

Why does washing your recycled fleece pollute more than cotton?

The paradox of recycled polyester is that the very act of caring for it is an act of pollution. While a cotton garment sheds biodegradable organic fibres, synthetic fabrics like polyester—virgin or recycled—shed microscopic plastic fragments. These microplastics are too small to be filtered out by wastewater treatment plants and end up in our rivers and oceans, where they are ingested by marine life and enter the global food chain. The fleece jacket, a staple of eco-conscious outdoor wear, is a particularly potent offender.

The scale of this pollution is alarming. Research from Plymouth University has provided stark evidence of the impact, finding that each cycle of a washing machine could release more than 700,000 plastic fibres into the environment. This isn’t a minor side effect; it’s a fundamental flaw of using plastic-based textiles. Mechanically recycled polyester can be even more problematic. The process of shredding, melting, and re-extruding the plastic shortens the polymer chains, creating a more brittle and less stable fibre that is prone to shedding.

So, while the label celebrates a bottle saved from a landfill, it omits the millions of plastic particles that will be shed into the water system over the garment’s lifetime. For a truly holistic environmental assessment, this ongoing microplastic pollution cannot be ignored. It represents a persistent, long-term contamination that stands in stark contrast to the rapid biodegradability of natural fibres like organic cotton or linen.

How does the recycled fibre lose strength after a second cycle?

The term “recycling” implies a process where a material can be remade into a product of equal quality, potentially indefinitely. This is known as closed-loop recycling. However, what happens with plastic bottles turned into t-shirts is fundamentally different. It’s an open-loop system, or more accurately, downcycling. The core reason for this is a process called polymer degradation, which occurs during mechanical recycling—the most common method for rPET.

When PET plastic is collected, shredded, melted down, and extruded into fibre, the long, strong polymer chains that give the plastic its structural integrity are broken. The heat and mechanical stress shorten these chains, resulting in a weaker, more brittle material. This degradation is cumulative. A bottle can be recycled back into a bottle a few times, but once it’s downcycled into a textile fibre, its potential for further high-quality recycling is virtually eliminated.

Most people believe that plastics can be infinitely recycled, but each time plastic is heated it degenerates, so the subsequent iteration of the polymer is degraded.

– Patty Grossman, Two Sisters Ecotextiles co-founder statement to FashionUnited

This physical degradation is not just a technicality; it has direct consequences for the consumer and the fashion system. Garments made from mechanically recycled polyester have a shorter lifespan. They are more prone to pilling, losing their shape, and tearing. This inherent weakness is, ironically, beneficial to the fast-fashion business model.

New organic cotton or recycled polyester: which is the lesser evil for the carbon footprint?

When comparing recycled polyester to organic cotton, there is no simple winner. Each material presents a different profile of environmental trade-offs. The choice of “lesser evil” depends entirely on which environmental impact you prioritise: carbon emissions, water usage, pollution, or end-of-life biodegradability. From a purely production-energy standpoint, recycled polyester appears to have a significant advantage.

Manufacturing rPET avoids the energy-intensive process of extracting and processing crude oil. According to a life cycle analysis cited by the Swiss Federal Office for the Environment, producing recycled polyester requires 59% less energy than virgin polyester. This translates to a lower initial carbon footprint for fibre production, an appealing metric that brands are quick to highlight. However, this single data point tells only part of the story.

Organic cotton, while more water and carbon-intensive to grow and process than producing rPET fibre, has two overwhelming advantages: it does not shed microplastics and it is fully biodegradable. The long-term environmental cost of plastic pollution from rPET is an externality that is rarely factored into these comparisons. A comprehensive view requires looking at the entire lifecycle, from creation to disposal.

The following table, based on data from multiple life-cycle analyses, provides a more nuanced comparison for a UK consumer, highlighting the complex and often contradictory nature of these materials. As the data from sources like Panaprium shows, the “better” choice is far from clear-cut.

Carbon Footprint Comparison: Organic Cotton vs Recycled Polyester for UK Consumers

Factor	Organic Cotton	Recycled Polyester
Production CO2	3.8 kg CO2/kg fiber	1.2 kg CO2/kg fiber
Transport Miles to UK	5,000+ miles (India/Turkey)	Variable (Europe/Asia)
Biodegradability	6 months	200+ years
Microplastic Release	None	700,000 fibers/wash
Water Usage	1,800 liters/kg	Minimal

The mistake of believing ‘100% recycled’ means infinitely recyclable

The label “100% recycled” is one of the most powerful and misleading phrases in sustainable fashion. It creates the impression of a perfect, closed-loop system where materials are used again and again without loss of quality. The reality is that a garment made from recycled bottles is the end of the line for that plastic. It cannot be mechanically recycled back into another garment, let alone a new bottle. This is the definition of downcycling.

Food-grade PET from bottles is a high-quality, clear plastic. When it’s melted, dyed, and turned into textile fibre, it becomes a low-quality material contaminated with dyes, finishes, and often blended with other fibres like elastane. This mixture makes it technically and economically unviable to recycle again using common mechanical methods. The garment’s only destinations are landfill, incineration, or, in rare cases, downcycling into an even lower-grade product like insulation or carpet padding.

Instead of being recycled into new bottles—a closed loop with high efficiency—these plastics are ‘downcycled’ into clothing, where their recyclability is extremely limited.

– Eco Aya Fashion Research, The Truth About Recycled Polyester in Fashion

This misleading communication has become so prevalent on the UK High Street that it has attracted regulatory scrutiny. The Competition and Markets Authority (CMA) has actively targeted fashion retailers for making vague and unsubstantiated green claims. Their Green Claims Code now requires brands to be truthful and clear about the entire lifecycle of a product, including its end-of-life limitations.

In a landmark intervention, the CMA secured commitments in March 2024 from ASOS, Boohoo, and George at Asda—three titans of UK fashion. These companies agreed to stop using misleading ‘100% recycled’ labels that fail to disclose that the resulting garment is no longer effectively recyclable. This action signals a crucial shift: the “recycled” claim is no longer enough; transparency about downcycling and end-of-life reality is now required.

What to do with your worn-out recycled clothes: the limits of the sorting bin

Once a recycled polyester garment reaches the end of its (often short) life, the consumer is faced with a significant problem. Unlike a pure cotton t-shirt that can be composted, a synthetic garment has no simple, sustainable disposal route. The local council’s recycling bin is not an option for textiles, and even specialised “take-back” schemes offered by retailers have severe limitations. The stark reality is that most used textiles in the UK end up as waste.

The scale of the problem is immense. Despite public awareness campaigns, a huge volume of clothing is simply thrown away. Groundbreaking WRAP’s 2024 research reveals that a staggering 49% of all used textiles in the UK are thrown directly into general household waste, destined for landfill or incineration. This figure exposes the systemic failure of our collection and recycling infrastructure.

Many UK retailers have introduced in-store collection boxes, but these are not the silver bullet they appear to be. While they divert clothes from immediate landfill, the “recycling” that occurs is not what most consumers imagine. Very few of these clothes are turned back into new fibres. Instead, the majority are sorted, baled, and exported to countries in the Global South, where they often flood local markets and end up in landfills there. It’s a system of waste displacement, not circularity.

For the eco-conscious UK consumer, navigating these options is difficult. Here is a realistic breakdown of the main take-back schemes and their ultimate outcomes:

• M&S Shwop: In partnership with Oxfam, this scheme is well-established. It accepts clothing of any brand, which is then resold, reused, or recycled through Oxfam’s channels.
• John Lewis & Partners FashionCycle: This scheme takes back used clothes and home textiles, working with specialist partners to prioritise resale and responsible recycling.
• Primark’s Textile Takeback: In partnership with Yellow Octopus, boxes in some stores collect textiles for sorting, with the stated aim of re-wear, reuse, or recycling.
• Online Alternatives: Services like Thrift+ and Reskinned specialise in facilitating the resale of higher-quality branded clothing, offering a better chance of extending a garment’s life.
• The Sobering Reality: As pointed out by industry experts at Reskinned, across all these schemes, only an estimated 1% of collected clothing is truly recycled back into new clothing. The vast majority is exported or downcycled.

How to spot the polyester that makes you sweat in the rayons of big chains?

Not all polyester is created equal. The comfort and breathability of a polyester garment depend heavily on the quality of the fibre and the construction of the fabric. Low-quality polyester, common in fast-fashion, is notorious for feeling plasticky, trapping moisture, and creating a clammy, uncomfortable feeling. This is because cheap, dense weaves with no technical properties act like a plastic sheet, preventing water vapour (sweat) from escaping.

High-performance polyester, used in quality activewear, is engineered for breathability. It often involves finer yarns, specific knit structures (like mesh), and chemical finishes that help to “wick” moisture away from the skin to the fabric’s surface, where it can evaporate. When shopping on the High Street, being able to distinguish between these types by touch and sight is a key skill for avoiding uncomfortable, sweat-inducing garments.

You don’t need to be a textile engineer to spot the difference. A simple in-store assessment can reveal a lot about a garment’s likely performance. This “hand-feel test” helps you look past the marketing tags and judge the fabric itself:

• The Feel Test: Rub the fabric between your thumb and forefinger. Cheap, non-breathable polyester often feels stiff, slick, or overly plasticky. Quality technical polyester feels softer and more pliable.
• The Light Test: Hold the garment up to one of the bright store lights. If no light penetrates the fabric (outside of the seams), it’s likely a very dense weave with poor air permeability. Better fabrics might show a faint matrix of light.
• The Stretch Test: Gently pull the fabric. A quality knit should bounce back to its original shape immediately. A cheap version may stay slightly stretched out or feel limp, indicating poor construction.
• The Surface Check: Look for an excessive, cheap-looking shine, which is often a sign of low-grade polymer. Also, be wary of “brushed” or “peach-finish” polyester in everyday wear; while soft, this finish can trap moisture unless it’s a specific technical fleece.
• The Label Decoder: Look for clarifying terms. Vague descriptions are a red flag. Phrases like “moisture-wicking,” “mesh panels,” or named technologies from brands like Nike (Dri-FIT) or Adidas (Climalite) indicate a fabric designed for performance. In UK stores like M&S, their “Goodmove” range is a good indicator of technical fabric, whereas basic ranges may be lower quality.

Why is the B Corp label more reliable than a brand’s self-declaration?

In a marketplace saturated with vague “conscious” and “eco” claims, third-party certifications provide a crucial layer of accountability. While any brand can launch a “sustainable collection,” achieving a certification like B Corp (Benefit Corporation) status requires a company to meet rigorous, externally verified standards across its entire operation—not just for a single product line. This holistic approach makes it a far more reliable indicator of a company’s genuine commitment.

A brand’s self-declared ethical range is, in essence, an internal marketing exercise. The criteria for inclusion are set by the brand itself, are often opaque, and can be changed at will. There is no independent body checking the claims. B Corp certification, by contrast, is a comprehensive and legally binding assessment.

B Corp certification is a rigorous, externally invigilated exam covering a company’s entire impact, whereas a brand’s self-declared ‘conscious collection’ is like marking your own homework.

– UK Sustainable Fashion Expert, B Corp fashion brand analysis

The B Corp assessment evaluates a company’s performance in five key areas: governance, workers, community, environment, and customers. It requires legal changes to the company’s articles of association to oblige it to consider the impact of its decisions on all stakeholders. This is a profound difference from a High Street giant that might produce a small “green” collection while its primary business model continues to rely on exploitative labour and environmental degradation. To see what this looks like in practice, we can look at a UK-based B Corp leader.

How to Spot Greenwashing in High Street Ethical Collections?

Greenwashing is the practice of making misleading or unsubstantiated claims about the environmental benefits of a product or company. The fashion industry, particularly fast fashion, is rife with it. Vague terms, cherry-picked data, and irrelevant claims are used to create a “halo effect,” making consumers feel good about their purchases without the brand having to make fundamental changes to its unsustainable business model. As a skeptical consumer, learning to decode these tactics is your most powerful tool.

The UK’s Competition and Markets Authority (CMA) has become a global leader in cracking down on this practice. Their “Green Claims Code” provides a clear framework for what constitutes a legitimate environmental claim. For brands, non-compliance is a serious risk. As legal analysts have noted, the CMA can now impose penalties of up to 10% of a company’s global turnover for misleading consumers—a fine that could amount to hundreds of millions for major High Street players.

For consumers, the CMA’s principles can be turned into a practical checklist for spotting greenwashing on the shop floor. It moves you from being a passive recipient of marketing to an active investigator. The core principle is to demand specificity and proof. A genuinely sustainable brand will be transparent and proud to provide details, while a brand that is greenwashing will hide behind vague, aspirational language. The absence of information is, in itself, a major red flag.

Ultimately, a brand’s sustainability cannot be judged by a single collection. You must look at the entire business. A company that drops 52 “micro-seasons” a year and promotes constant, disposable consumption cannot be considered sustainable, no matter how many of its t-shirts are made from recycled bottles. True sustainability requires a systemic shift towards producing fewer, more durable items and taking responsibility for their entire lifecycle.

Armed with this engineering perspective, the next step is to use this knowledge not just for personal purchasing decisions, but to challenge brands. Ask questions on social media, email customer service, and demand a level of transparency that goes far beyond a simple “recycled” tag. Your critical voice as a consumer is essential in pushing the industry towards genuine circularity.