Recycled polyester appears on an enormous number of garments as the primary environmental claim. It is a genuine improvement on one dimension and it is doing less than the marketing implies.
What it actually is
Most of it comes from bottles rather than from clothing.
Bottles are collected, cleaned, broken down and spun into fibre. This is established, works at scale, and produces a material that performs comparably to virgin polyester.
The reason it comes from bottles rather than from garments is that textile-to-textile recycling is genuinely difficult — clothing is a mixture of fibres, dyes, elastane and trims, and separating those at scale remains largely unsolved.
Which is the first thing the claim obscures. A recycled polyester garment is generally not made from old garments and does not represent a closed loop for clothing.
The bottle argument
The objection that is worth taking seriously.
Bottle-to-bottle recycling is an established closed loop — a bottle can become a bottle repeatedly.
Diverting bottles into textiles removes them from that loop, since a garment cannot become a bottle and generally cannot become another garment.
So the effect may be to convert a recyclable material into a terminal use, which is a downgrade rather than a saving.
Beverage industry bodies have made this argument, which gives them an interest in it, and the underlying point stands independently.
What it does and does not address
Being precise about the benefit.
It reduces the use of virgin petroleum feedstock for that fibre, which is a real reduction with real associated emissions savings.
It does not address microfibre shedding, which is identical for recycled and virgin polyester. Synthetic textiles release fibres during washing and wearing, those fibres are found throughout the environment, and this is an active area of research and concern.
It does not address end of life. A recycled polyester garment is as difficult to dispose of as any other synthetic.
And it does nothing about the quantity produced, which is the variable that dominates every other consideration.
The volume problem
The point that makes most material-level claims secondary.
Global clothing production has risen enormously over recent decades while the number of times a garment is worn before disposal has fallen.
Which means efficiency improvements per garment are being outpaced by the increase in garments.
A material improvement of some percentage applied to a volume that has doubled produces a worse outcome in total, and this is the arithmetic that most sustainability marketing avoids.
The certification landscape
Worth knowing because the claims are checkable.
Standards exist that verify recycled content through the supply chain, and a certified claim is meaningfully different from an uncertified one.
What certification generally verifies is content and chain of custody rather than environmental outcome, which is a narrower claim than buyers assume.
Regulators in several jurisdictions have taken action against unsubstantiated environmental claims in clothing, and rules requiring substantiation have been tightening.
Which has already changed how some brands describe their products, generally toward vaguer language rather than better evidence.
What actually reduces impact
In rough order, according to the analyses I have seen.
Buying less, which dominates everything else.
Wearing things longer, since impact per wear falls with every additional wear.
Repairing rather than replacing.
Buying second-hand, which adds no new production.
Washing less often and at lower temperatures, which is a substantial share of a garment's lifetime footprint and is entirely within the owner's control.
Material choice appears well below all of these, which is inconvenient because material choice is the only one the industry can sell you.
What I do with the claim now
Treat it as mildly positive and not as a reason to buy.
A recycled polyester garment I would have bought anyway is marginally better than the virgin equivalent.
A recycled polyester garment bought because of the claim is an additional garment, which is worse than not buying it, regardless of what it is made from.
That distinction is the whole of it, and it is precisely the distinction the marketing is constructed to blur.
Natural fibres are not automatically better
Worth stating because the obvious response to synthetic concerns is to assume the alternative is clean.
Conventional cotton has substantial water and land requirements and, in some growing regions, significant pesticide use.
Wool and leather carry their own impacts, and comparisons between fibre types depend heavily on which impacts are weighted.
Life cycle assessments comparing fibres produce different rankings depending on methodology, which is a genuine limitation rather than an evasion.
Which returns to the same conclusion — the number of garments dominates the material choice, and that is the variable within a buyer's control.
Microfibres and what reduces them
Since it is the impact most directly within a wearer's control.
Shedding is highest in the first few washes of a new garment and declines thereafter, which is an argument for buying less rather than for anything else.
Washing less frequently, at lower temperatures, with fuller loads and shorter cycles reduces it measurably.
Filter bags and machine filters capture a proportion, and some jurisdictions have moved toward requiring filters on new machines.
None of this eliminates the issue and all of it is cheap and available now.