The short answer
No. Cotton is a plant fibre and it does not shed microplastics. It sheds fibres, because every textile does, but cellulose is not a polymer that persists as plastic.
The complication is that the question is almost always asked about a garment, and that answer is about a fibre. Very few garments are cotton from end to end.
Why cotton is not plastic
Polyester, nylon, acrylic and elastane are petrochemical polymers spun into thread. When they abrade, what comes off is plastic and it does not break down.
Cotton is cellulose. When a cotton fibre comes loose in the wash, it is a cotton fibre. That is the whole of the distinction, and it holds regardless of how the cotton was farmed. If you want the mechanism in full, we covered how and where fibres come loose in the guide this article sits under.
Cotton does not shed microplastics. That is a fact about the fibre, not a certificate for the garment.
What about viscose, modal and lyocell?
These sit in a category of their own and they cause more confusion than anything else on a label.
They are cellulosic. The raw material is plant matter, usually wood pulp, so what comes off them in the wash is not plastic either. On the microplastics question specifically, they behave like cotton rather than like polyester.
What separates them from cotton is how much has to happen chemically to turn wood into a fibre soft enough to wear. That is a real question, and it is a different one. It does not show up anywhere in a composition percentage, which is the recurring problem with reading garments off labels.
Where does the synthetic hide in a garment labelled cotton?
The composition percentage on a care label describes the fabric. It does not describe the finished object. Five places worth checking, in the order they are most likely to catch you out:
- The rib at cuffs, neckline and waistband. Almost always contains elastane.
- The sewing thread. Frequently polyester, because it is stronger than cotton thread.
- Prints. Plastisol sits on top of the cloth as a layer of plastic.
- The care label itself. Often woven polyester, which is why it is the scratchy part.
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Zips, poppers and drawcords.
None of these appear in the percentage. A garment can be honestly labelled 100% cotton and carry all five.
The rib, and ours
Elastane is the one that deserves numbers, because it appears in quantities small enough to read as harmless.
Research published in Science of the Total Environment[1] found that one square metre of fabric containing just 2% elastane can release up to 28,100 microfibres in its first wash. Elastane holds the surrounding fibres under tension, and tension makes them break.
The rib at the cuffs and neckline of our garments is 95% organic cotton and 5% elastane. The jersey and French terry bodies are 100% organic cotton. We said this in the microplastics guide and it is worth repeating here, because this is the article somebody looking for the answer will actually land on.
A rib with no recovery stretches out within a season, and a garment with a gaping neckline gets thrown away long before it has been outgrown. Five percent in the trim is the trade we decided we could defend. The full composition of every fabric we use is published, so you can weigh it yourself.
What "natural" does not automatically mean
Here is the part most articles on this subject leave out, including the ones written by brands that sell cotton.
A systematic review published in Environmental Research Letters in 2026[2] put the question directly: are natural textile fibres environmentally benign? It examines the chemical processing behind them alongside microfibre pollution, which is precisely the part of the story a fibre percentage cannot tell you. Scouring, bleaching, dyeing and finishing all happen after the plant and before the garment.
A fibre can be natural and the process that turned it into cloth can still be the problem. That is why fibre certification and process certification are different instruments, and why the difference between GOTS and OEKO-TEX is worth ten minutes of anyone's time.
How to read your own label in thirty seconds
Find the composition percentages, usually in a side seam or at the back of the neck. Then look at what they do not cover.
Run a finger around the cuff and the neckline and feel whether the rib springs back. Check what the care label itself is made of. Look at whether a print sits on top of the cloth or is dyed into it.
Two habits make this faster over time. Check the trim before the headline percentage, because the percentage is the part that is already telling you the truth and the trim is the part that is not covered. And weight the check towards the garments that go through the machine every week, because those are where the difference accumulates.
If the fabric is a natural fibre and the trim is small, you are most of the way there. If the fabric is polyester, the trim is beside the point.
On our site: Our materials · Glossary
