Author : Sarah Perreard, Earth Action

The fashion industry spent the better part of a decade building “made from recycled bottles” into one of its most relied-upon sustainability narratives. It appeared on hangtags, in annual reports, in marketing campaigns. It gave brands a story that was easy to tell and, crucially, one that felt unassailable: we diverted plastic from landfill and ocean, we closed a loop, we did something good.

That story has a structural problem. And the window for getting ahead of it is narrowing.

What the claim actually says

“Made from recycled polyester” or “made from recycled bottles” is a statement about material origin. It says where the fiber came from. It says nothing about how the garment performs environmentally during its use life, including how many microfibers it releases into waterways every time it is washed.

That distinction did not matter much when microfiber regulation was theoretical. It matters a great deal now that regulators, enforcement agencies, and plaintiff lawyers are looking specifically at the gap between what brands say and what science supports.

What the research actually shows

The evidence on whether recycled polyester (rPET) sheds more or fewer microfibers than virgin polyester is contested. Studies have reached different conclusions, and the reasons for that are worth understanding.

A peer-reviewed study from Çukurova University (Özkan and Gündoğdu, 2021) found rPET knit fabrics shed around 2.3 times more than virgin polyester by weight. The researchers attributed this to shorter fiber lengths and reduced breaking strength in mechanically recycled fibers: the recycling process degrades the polymer chains, producing a shorter-staple fiber that is structurally more prone to fragmentation. In December 2025, the same research group tested 51 commercial garments from five major brands (Adidas, H&M, Nike, Shein, and Zara) in a study commissioned by the Changing Markets Foundation. Recycled polyester garments shed 55% more microfibers by particle count than virgin polyester, and the particles released were also around 20% smaller on average, reinforcing the same mechanistic pattern.

The Microfibre Consortium’s (TMC) 2023 research across 251 diverse fabrics, using a different test method on isolated swatches rather than full garments, found no statistically significant difference between rPET and virgin polyester. A 2024 paper in Environmental Pollution also found higher shedding from rPET under household washing conditions. Some studies, including work on specific fleece constructions, have found rPET shedding comparably to or even less than virgin equivalents, driven by how the recycled fiber compacts in certain fabric structures.

The honest reading of all of this: the studies conflict. The conflict is partly real (rPET performance varies by construction and recycling method) and partly methodological (test method, fabric type, and whether shedding is measured on swatches or full garments all affect outcomes). What no study has found is that rPET reliably sheds less. The claim that recycled content reduces microfiber emissions is not supported by the literature.

A measurement problem that matters

Most of this research measures shedding by weight, in milligrams per kilogram of fabric. That is a reasonable starting point, but it is not the whole picture.

Particle count and particle size tell a different story. The mechanistic reason that mechanically recycled polyester may shed more is that it starts with shorter fiber lengths, which means the fragments it releases are also likely to be smaller. A fabric releasing a higher number of finer particles may appear similar to, or lower than, a virgin equivalent when measured by mass, because smaller particles weigh less individually. The same weight of released material can represent a very different number of particles, with very different behavior in the environment and in the human body.

This matters because particle size is not just an academic distinction. Smaller particles penetrate further into lung tissue, pass more readily through biological membranes, and are harder to capture in wastewater treatment systems. The growing body of research on nanoplastics and human health, including links to cardiovascular and neurological outcomes, is built on the observation that the smallest particles carry disproportionate biological risk. Standard weight-based shedding metrics were not designed with this in mind.

Whether rPET systematically produces smaller particles than virgin polyester is an area of active research. The directional logic of the mechanistic argument is not reassuring, and we expect the science here to develop significantly over the next few years. We are not in a position to make a definitive claim. But we are in a position to say that weight-based metrics alone are insufficient to characterize the environmental and health profile of rPET shedding, and that brands relying on those metrics to assert equivalence are standing on uncertain ground.

What the science does agree on

Across all of this research, one finding is consistent: the recycled content of a fiber does not reliably predict its shedding behavior. Shedding is driven by fabric construction, specifically yarn type, fiber length, weave structure, and finishing treatments. A tightly woven fabric from virgin polyester may shed dramatically less than a loosely knitted fabric from recycled polyester, and vice versa. Whether the polyester originated from a bottle or a pellet is not the determining factor.

That has a practical implication. If a brand wants to make a credible claim about low microfiber impact, the relevant question is not what the feedstock was. It is how the product was designed, what test data exists for that specific construction, and what that data shows.

Recycled polyester still does what it has always done on the material side: it reduces dependence on virgin fossil feedstock and diverts plastic that would otherwise go to landfill or worse. That value is real, and nothing here argues against using recycled content as a material choice. The shift is in what the claim is starting to communicate alongside it. “Made from recycled bottles” was written and approved as a neutral statement about origin. If the weight of evidence keeps moving the way it has, that same sentence stops being neutral. It starts reading as an admission: more microfibers shed, and a higher share of the smaller, more biologically active particles that current weight-based testing was never built to catch. A brand would be disclosing the risk on its own hangtag without meaning to.

The claim that is becoming a liability

“Made from recycled bottles” has until recently been treated as a factual and therefore safe claim. It describes material origin and makes no explicit promise about environmental performance. Legal teams approved it on that basis: it is true, it is verifiable, it does not assert a performance outcome.

But that logic may not hold for much longer. Environmental claims are evaluated not just on what they say explicitly but on what a reasonable consumer understands them to imply. Consumer psychology research on sustainability claims describes this as a halo effect: a single positive attribute, such as recycled content, leads consumers to assume a product is more broadly environmentally responsible than the claim itself actually supports. This pattern has been documented across eco-labels and certifications generally, and it is the same dynamic the EU Commission’s own 2020 review of environmental claims was responding to, when it found that 53% of the claims examined were vague, misleading, or unfounded, and over 40% were unsubstantiated by any evidence at all. There is no reason to expect “made from recycled bottles” to be an exception to a pattern that well-established.

If the weight of evidence keeps moving toward rPET shedding more particles, or shedding particles that are smaller and more biologically active, “made from recycled bottles” stops functioning as a neutral origin statement. It starts functioning as a disclosure, the brand’s own label confirming the product sheds more of the particles that matter most, written in language nobody intended as an admission. At that point, the gap between what the claim communicates and what the evidence shows is exactly the kind of gap that regulators enforcing the EU Empowering Consumers Directive and plaintiff lawyers in consumer protection cases are structured to exploit.

The EU Empowering Consumers Directive (ECD), which enters enforcement in September 2026, makes unsubstantiated environmental claims illegal across EU member states. Several national consumer protection agencies have already named rPET as an enforcement focus. The UK’s Competition and Markets Authority has been actively enforcing its Green Claims Code since autumn 2025. In the United States, state-level enforcement is accelerating in parallel with a more fragmented but increasingly active federal posture on environmental claims.

Brands that have built commercial narratives on recycled content as an implied environmental differentiator are carrying real exposure. The claim that felt safe in 2021 is materially more complicated in 2026, and the direction of travel on both the science and the regulatory landscape does not favor waiting.

What this means in practice

Three things follow from this.

First, if your brand makes recycled content claims in any consumer-facing communication, it is worth reviewing exactly what those claims say and what a reasonable consumer is likely to infer from them. The distinction between “made from recycled materials” and “made from recycled materials for lower environmental impact” is legally meaningful. The former is a statement of fact. The latter is a performance claim that requires substantiation.

Second, the appropriate substantiation for a microfiber-related claim is product-level shedding data for your specific constructions, not an inference from feedstock type. Recycled content is not a proxy for shedding performance. It has never been a reliable one, and the science is moving in a direction that makes that clearer, not less clear.

Third, the particle size and count question is worth tracking. The field is moving. When peer-reviewed research begins directly comparing rPET and virgin polyester particle size distributions in controlled conditions, it will either support or undermine the current weight-based equivalence arguments. Brands that have built claims on those arguments should be monitoring that literature and have a plan for what they will do if the findings are unfavorable.

None of this means recycled polyester has no role in a responsible sourcing strategy. Reducing dependence on virgin fossil-derived materials has value in terms of carbon footprint and waste diversion. Those are real benefits. The problem is using recycled content as a signal of broader environmental responsibility without the data to back that up in the specific dimension of microfiber emissions, particularly as that dimension becomes legally and commercially more significant.

The science on rPET and shedding is not settled. But the direction it is moving in matters, because a claim that currently reads as safe is on track to read as a confession: more microfibers, smaller and more dangerous ones, stated voluntarily on the brand’s own packaging. That is precisely the reason to act now, not the reason to continue as before.

Earth Action develops the Microfiber Footprint methodology and works with brands and coalitions to build evidence-based strategies for microfiber reduction. We have also put together a detailed regulatory intelligence report covering the EU and global compliance landscape jurisdiction by jurisdiction, and a Microfiber Readiness Assessment that helps brands identify where their claims and data may be exposed. Neither is publicly available, but if you are working through claims review or shedding data questions internally, write to us at contact@e-a.earth.