69% of All Clothing Is Now Synthetic
Let that number land for a second. More than two-thirds of every fibre produced on the planet is synthetic — overwhelmingly polyester, which is just PET plastic spun into thread. The same stuff your water bottle is made from, now wrapped around your body.
In 2000, synthetic fibres accounted for roughly 50% of global textile production. By 2023, that number had climbed past 69%, driven almost entirely by the explosion of fast fashion. The economics are brutally simple: polyester costs about half as much as cotton per kilogram, it is easier to dye, it wrinkles less, and it lets brands hit the price points that move volume.
The result? An industry that produces over 100 billion garments a year, the majority of them petroleum-based, many worn fewer than ten times before being discarded. Every single one of those garments will shed microplastics with every wash — tiny plastic fragments that end up in rivers, oceans, and eventually your bloodstream.
This is not a niche environmental concern. This is the baseline of modern clothing.
Brand by Brand: Who's Worst?
We analysed fabric composition data across thousands of current listings from six of the biggest fast fashion retailers. Here is where they land.
| Brand | Approx. Synthetic % | Verdict |
|---|---|---|
| Shein | ~82% | The worst offender by a wide margin. The vast majority of Shein garments are polyester-dominant. Expecting natural fibres here is like expecting nutrition at a petrol station. |
| Boohoo | ~74% | Not far behind Shein. Ultra-low price points require ultra-cheap materials — and that means polyester, acrylic, and nylon in almost everything. |
| ASOS | ~68% | A mixed bag — ASOS carries third-party brands too — but their own-label lines lean heavily synthetic. Their "Responsible Edit" still features plenty of polyester. |
| Zara | ~65% | Better than the ultra-fast players, but still majority synthetic. Zara's premium lines use more cotton and wool, but the core range is polyester city. |
| H&M | ~61% | H&M publishes more sustainability data than most — and still lands at 61% synthetic. Their "Conscious" line has improved, but the bulk of inventory tells a different story. |
| Mango | ~57% | The "best" of a bad lot. Mango has made more visible moves toward natural fibres, particularly in their Committed collection. Still majority synthetic overall. |
The pattern is obvious: the cheaper the brand, the higher the polyester percentage. Price has to come from somewhere, and it comes from replacing cotton, linen, and wool with petroleum-derived plastic. Every single time.
Why Brands Love Polyester
Brands do not use polyester because it is better. They use it because it is cheaper. Here is the full picture:
- Cost. Polyester costs roughly $0.50-0.80/kg compared to $1.50-2.50/kg for cotton. At the scale fast fashion operates — billions of garments — that difference is worth hundreds of millions in margin.
- Wrinkle resistance. Polyester holds its shape through shipping, folding, and display. It photographs well. It looks "new" longer on the rack. Natural fibres crease, which costs brands returns and dissatisfied reviews.
- Speed to market. Polyester can be dyed faster, in more colours, with more consistency than cotton. When you are churning out 6,000 new styles a week (yes, Shein does this), speed beats quality every time.
- Margins. A polyester dress that retails for $25 might cost $3 to produce. The same silhouette in cotton or linen would cost $7-9. That margin gap is the entire business model of fast fashion.
- Durability theatre. Polyester does not pill as visibly as some natural fibres in the short term, which gives the illusion of quality. Of course, it is also accumulating static, trapping odours, and shedding microplastics — but those problems are invisible at point of sale.
None of these benefits are for you. They are for the brand's bottom line. You get to wear the plastic.
The Greenwashing Playbook
Fast fashion knows you are getting wise to polyester. So they have developed a playbook to make you feel better about buying it anyway.
"Recycled Polyester"
This is the big one. Brands now trumpet "recycled polyester" as though it solves the problem. It doesn't. Recycled polyester still sheds microplastics at the same rate as virgin polyester. It still takes 200+ years to decompose. It still traps heat and odour against your skin. The only difference is the feedstock — recycled PET bottles instead of fresh crude oil. That is marginally better for carbon emissions at the production stage, and completely irrelevant to every other problem polyester causes.
Worse: most "recycled polyester" garments cannot themselves be recycled. They end up in landfill just like their virgin counterparts. It is circular branding, not circular fashion.
"Conscious" and "Committed" Collections
H&M's Conscious line. Mango's Committed collection. Zara's Join Life. These capsule collections get the press releases, the Instagram campaigns, and the in-store signage. They typically represent 5-15% of a brand's total output. The other 85-95%? Business as usual. Full of polyester, produced at breakneck speed, sold at prices that are only possible because the materials are dirt cheap.
These collections exist to give you permission to keep shopping at the same brand. That is their function.
Vague Language
"Sustainably sourced." "Eco-friendly materials." "Made with care for the planet." None of these phrases have legal definitions. None of them tell you what the garment is actually made from. The composition label does — and brands know most people never read it.
Which is exactly why we built Fibr.
How to Shop Smarter
You do not have to become a monk. You just need better information at the moment of decision. Here is how:
- Check the composition label. Every time. Before anything else, look at what the garment is made from. If it says polyester, nylon, or acrylic — that is plastic. Full stop.
- Use Fibr. If you shop online at Zara, H&M, or Mango, install Fibr and the composition data is right there on the product image. No clicking into details, no squinting at fine print. Green badge means natural fibres. Red badge means synthetic. Done.
- Prioritise natural fibres. Cotton, linen, hemp, wool, silk. These have been clothing humans for thousands of years. They breathe, they biodegrade, and they do not shed plastic into your washing machine. They cost more — because they are worth more.
- Buy less, buy better. One cotton shirt worn 100 times beats ten polyester shirts worn 10 times each — for your wallet, your skin, and the ocean.
- Ignore the marketing. "Recycled polyester" is still polyester. "Conscious collection" is still fast fashion. Read the label, not the tagline.
Frequently Asked Questions
Which fast fashion brand uses the most polyester?
Shein leads the pack at roughly 82% synthetic composition across its catalogue. Boohoo follows at around 74%. The pattern is consistent: the cheaper the brand, the higher the polyester content. Brands like Mango and H&M sit lower but still produce majority-synthetic ranges. Use Fibr to see exact composition data for every product as you browse.
Is fast fashion all polyester?
Not literally all, but close. Across the major fast fashion brands, synthetic fibres — predominantly polyester — account for 57-82% of garments. You will find cotton and linen pieces, but they are the minority. The economics of fast fashion demand cheap materials, and polyester is the cheapest textile fibre available. Natural fibre garments exist in these stores, but you have to actively look for them — which is exactly what Fibr helps you do.
How do I avoid synthetic fast fashion?
Three steps. First, always check the fabric composition label — on the garment or the product page. If it lists polyester, nylon, or acrylic as the primary fibre, it is plastic. Second, install Fibr to see composition data directly on product images when shopping at Zara, H&M, and Mango. Third, prioritise garments made from cotton, linen, hemp, wool, or silk — they cost more per unit but last longer, breathe better, and do not shed microplastics.