30 July 2026 · 7 min read · By Sanjeewa Dehiwalage
Recycled polyester: what the claim means, and what it does not
Recycled polyester is the most common recycled content claim in apparel, and the most commonly misread. The useful questions are where the feedstock came from, which route processed it, and what that does to the yarn you receive.
- materials
- recycling
- polyester
- sustainable fashion
Feedstock and route
Most commercial recycled polyester still comes from post-consumer bottle flake rather than from garments. That is genuine recycling, but it moves material out of an existing bottle loop rather than closing an apparel loop.
Mechanical recycling remelts and extrudes flake. Chemical depolymerisation breaks the polymer down and rebuilds it, which tolerates dirtier feedstock and can reach fibre-grade quality more consistently — at higher cost and, currently, smaller capacity.
What changes in the yarn
Intrinsic viscosity drops during mechanical processing, so bottle-grade flake lands in the apparel fibre-grade range rather than staying at bottle specification. Well-run lines produce fibre comparable to virgin fibre-grade material; poorly controlled feedstock produces inconsistent tenacity.
Dye behaviour is the practical risk. Mixed feedstock can give uneven dye uptake and shade variation between lots, which shows up as batch-to-batch colour issues rather than as a fibre test failure.
Verification
Recycled content is a chain-of-custody claim, verified by certification and transaction documents, not by a test on the finished garment. Ask for the documentation trail and for lot-level dye consistency data, and treat any percentage without a chain of custody as unverified.
Key takeaways
- Most recycled polyester is bottle-derived, not garment-derived.
- Expect dye consistency, not fibre strength, to be the operational risk.
- Recycled content is proven by chain of custody, not by testing the garment.
Where this is taught
More on circular fashion
Figures are indicative of common practice, not standards or legal limits. Self-study material, not certified training.