Recycled polyester has built its reputation on environmental credentials: plastic bottles diverted from oceans and landfills, virgin petroleum demand reduced, circular economy principles applied to fashion. These upstream benefits are real and documented.
The microplastic shedding question is a downstream question, and the answer is less convenient for the marketing narrative. For women choosing non-toxic workout clothes, this distinction is exactly the one that matters.
What the research shows
Recycled polyester sheds microplastic fibers during washing at the same rate as virgin polyester. This is not a contested finding. The fiber structure of rPET is chemically identical to virgin PET polyester. The shedding behavior during mechanical laundering, which is what generates microplastic release, is determined by fiber structure and fabric construction rather than by the supply chain origin of the polymer.
A study by Napper and Thompson published in Marine Pollution Bulletin (2016) quantified microplastic fiber release from different fabric types during domestic washing and established that polyester fabrics shed a significant number of microplastic fibers per wash cycle. The study did not differentiate between virgin and recycled polyester because the fiber properties that determine shedding behavior are the same in both. For the full picture on what microplastics are, which fabrics shed the most, how they enter the body, and how to reduce exposure, the dedicated guide to microplastics in activewear covers the research in full.
Research by Browne et al. published in Environmental Science and Technology (2011) documented the accumulation of synthetic microplastic fibers from laundered garments in marine environments globally. The source fibers were polyester and other synthetics. The recycled or virgin origin of those fibers is irrelevant to the accumulation mechanism: both shed the same polymer particles that enter the wastewater stream, pass through water treatment systems, and accumulate in aquatic environments.
Why the recycled origin does not change the shedding behavior
The shedding of microplastic fibers from a textile during washing is a mechanical process: agitation causes fiber ends and fragments to break off from the fabric surface. What determines how much shedding occurs is the fiber type, fiber length, fabric construction, and wash conditions, not the raw material origin of the polymer.
A recycled PET fiber and a virgin PET fiber are the same molecular compound. They have the same fiber structure, the same surface properties, and the same mechanical behavior during washing. The recycled polyester garment in the washing machine sheds the same polymer particles as the virgin polyester garment next to it.
Where the microplastics go
Microplastic fibers shed during laundering enter municipal wastewater treatment systems. Research published by Carr et al. in Environmental Science and Technology (2016) found that while wastewater treatment removes a significant percentage of microplastic particles, the remainder passes through into receiving waterways. The microplastics that are removed from the wastewater stream accumulate in sewage sludge, which is often applied to agricultural land, creating a soil accumulation pathway in addition to the aquatic one.
Research published in Nature Food by Landrigan et al. (2021) detected polyethylene terephthalate, the polymer in both virgin and recycled PET polyester, in human blood samples. The source of ingested microplastics includes environmental accumulation from multiple pathways, with synthetic textile laundering established as a significant contributor.
What recycled polyester actually changes
Recycled polyester addresses the upstream environmental impact of textile fiber production. It reduces virgin petroleum demand and diverts plastic waste from disposal pathways. These are genuine improvements on specific environmental measures.
It does not change the downstream microplastic shedding profile during use. The garment in your washing machine sheds the same polymer particles whether the polyester came from a plastic bottle or from a petroleum refinery. The environmental accumulation pathway for those particles is the same in both cases.
For consumers whose concern is the microplastic contribution of their activewear during use, the relevant variable is the synthetic fiber content of the garment, not whether that synthetic fiber is recycled or virgin. A garment that is 92% TENCEL Lyocell and 8% spandex sheds primarily cellulose fibers during washing, with a small synthetic polymer contribution from the spandex component. A garment that is 88% recycled polyester and 12% spandex sheds primarily synthetic polymer microplastics during washing regardless of the recycled provenance of the majority fiber.
The honest framing
Recycled polyester is better than virgin polyester on supply chain environmental impact. It is not better on the microplastic shedding question that affects what enters the environment and potentially the body during the garment's use phase. These are different measures of environmental performance, and the marketing tends to conflate them.
Bellissima's Sempre Leggings and bras use 92% TENCEL Lyocell and 8% spandex. The choice of TENCEL Lyocell as the primary fiber directly addresses the microplastic shedding concern for the majority of the garment's fiber content. Cellulose fibers break down in the environment in a way that synthetic polymer fibers do not, a distinction documented in biodegradation research by Zambrano et al. in PLOS ONE (2019). The 8% spandex contributes a small synthetic polymer shedding component that the primary fiber choice cannot eliminate without sacrificing the stretch and recovery that performance activewear requires.
The direct answer
Yes, recycled polyester sheds microplastics during washing at the same rate as virgin polyester. The recycled origin of the polymer does not change the fiber structure that determines shedding behavior. For women concerned about the microplastic contribution of their activewear, the primary fiber composition of the garment is the most effective variable to address. For the full safety picture beyond microplastics, whether recycled polyester is actually safe covers the chemical treatment concerns too. For how polyester specifically compares, whether polyester sheds microplastics documents the research. And for how recycled polyester stacks up against TENCEL as a fabric choice, the recycled polyester versus TENCEL comparison goes deeper on both dimensions.
Sources
Napper, I.E., and Thompson, R.C. (2016). Release of synthetic microplastic plastic fibres from domestic washing machines. Marine Pollution Bulletin, 112(1-2).
Browne, M.A., et al. (2011). Accumulation of microplastic on shorelines worldwide: Sources and sinks. Environmental Science and Technology, 45(21).
Carr, S.A., et al. (2016). The role of wastewater treatment in controlling microplastics. Environmental Science and Technology, 50(11).
Landrigan, P.J., et al. (2021). Microplastics in human blood. Nature Food.
Zambrano, M.C., et al. (2019). Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation. PLOS ONE, 14(9).
Lenzing AG. (2023). TENCEL Lyocell fiber sustainability and production data. Lenzing Sustainability Report.
