Is recycled polyester actually sustainable?

Walk into almost any activewear store right now and you will find an "eco" or "conscious" line, and almost all of those lines are made of recycled polyester. The story is consistent. Bottles fished from the ocean, plastic kept out of landfill, performance fabric with a smaller footprint.

Some of that is true. Some of it is the most successful piece of marketing the activewear industry has run in twenty years.

We chose not to use it. Here is why.

What recycled polyester actually is

Recycled polyester, usually labelled rPET, is made by taking polyethylene terephthalate from existing sources, breaking it down, and re-extruding it as fibre. The most common source is post-consumer PET bottles. Some brands also use post-industrial scraps from textile manufacturing, and a smaller number use ocean-recovered plastic.

The process is real. The output is genuinely made from previously used plastic. There is no fabrication in that part of the story. What the marketing usually leaves out is what happens to that fibre once it becomes activewear.

The four claims, and what the data says

There are four things brands typically claim about recycled polyester. Each one is partially true and partially incomplete.

Claim 1: "It diverts plastic from landfill and oceans."

Partially true. Bottle-to-fibre recycling removes some PET from waste streams. The catch: bottle-to-bottle recycling, where used PET becomes new bottles, is a more closed loop. Once a bottle becomes a polyester garment, it cannot be recycled again economically. The fibre is too short, the dyes are mixed in, and there is almost no infrastructure for textile-to-textile recycling at scale. So the bottle does not get recycled forever. It gets recycled once, into a garment, and then it ends up in landfill or incineration anyway, just on a slightly delayed timeline.

Claim 2: "It has a lower carbon footprint."

Partially true. rPET production typically uses 30 to 50 percent less energy than virgin polyester production. That is a real reduction. The catch: the use phase of activewear (washing, drying, eventually disposing) accounts for more than half of total lifetime emissions for most garments. The fibre's production footprint is one slice of a larger pie. Lowering that slice is good. It does not make the overall garment low-impact.

Claim 3: "It performs the same as virgin polyester."

True. And that is the problem. Recycled polyester sheds microplastics at the same rate as virgin polyester. It traps heat and bacteria the same way. It off-gasses chemical residue from manufacturing the same way. It does not biodegrade. The fibre is, structurally and chemically, polyester. Recycling the source did not change what the fibre is. For activewear specifically, fabric worn against skin, washed weekly, in direct contact with sweat, the chemical and microplastic concerns from polyester remain. We get into those concerns in why your sportswear makes you itch.

Claim 4: "Ocean plastic activewear cleans up the ocean."

Mostly marketing. Verifiable ocean-recovered plastic accounts for a tiny fraction of the rPET supply. Most "ocean plastic" claims refer to plastic recovered from coastal waste streams or rivers, not from the open ocean. Some claims refer to "ocean-bound" plastic, plastic that might have ended up in the ocean, which is a much weaker definition. There are a small number of brands genuinely using verified ocean-recovered material. They are usually very explicit about volumes and sources, because the volumes are small. When a major activewear label sells a full collection branded as "ocean plastic," the math rarely adds up.

When recycled polyester does make sense

We are not anti-recycling. We are anti-using-recycling-as-cover. For products where polyester is the right choice for performance reasons, recycled is genuinely better than virgin. That includes backpacks, tents, outdoor hard-shell jackets, ropes, certain technical outerwear. These products do not sit against skin all day. They do not get washed weekly. The microplastic and chemical concerns are much lower in those use cases. For activewear, fabric worn against skin during sweat, washed every wear or two, the case is different. The downsides of polyester as a fabric are not solved by changing where the polyester came from. The full comparison is in cotton vs polyester for fitness.

What we did instead

We use 92% GOTS-certified organic cotton and 8% spandex. The cotton has a higher per-kilogram footprint than recycled polyester at the fibre level. It uses water during cultivation. It is not synthetic-free. But cotton biodegrades. It does not shed microplastics. It does not trap chemical residue against skin in the same way. And we are honest about the 8% spandex rather than burying it under a recycled-fibre claim. We say more about what we do and do not claim in we are not perfect, and about which certifications actually mean something in what GOTS, OEKO-TEX and Fair Wear actually mean.

We made a different trade-off. We are not pretending it is perfect. We are saying that for activewear, specifically, recycled polyester is solving a smaller part of the problem than the marketing suggests, and we did not want to be one of the brands selling that story.

LAINE HILL

Continue reading

• We are not perfect. What we do, what we deliberately do not claim, and how we read greenwashing.
• For half a century we got it wrong. What polyester does, and why we built something different.
• What GOTS, OEKO-TEX and Fair Wear actually mean. Which certifications mean something, and what each one ignores.