Thread Report · 47 products analyzed · Updated June 12, 2026

What is COS made of?

Better than most. COS averages 74.8% natural fibre, which puts them ahead of many competitors. But not everything is equal.

According to Fibr's Thread Report (June 2026), 8.5% of COS's 47 analysed products are majority-synthetic, with an average natural-fibre content of 74.8%.

47Products Analyzed
74.8%Avg Natural Fibre
8.5%Polyester-Heavy
44.7%Nearly All-Natural

44.7% of COS products are nearly all-natural (95%+). That's genuinely good — better than most fast fashion retailers.

The full picture on COS.

COS is one of the stronger performers in our dataset, averaging 74.8% natural fibre across 47 products we analyzed. Only 8.5% of products are polyester-heavy — relatively low compared to many retailers. On the bright side, 44.7% of COS products are made almost entirely from natural fibres (95%+). The most common fibre across COS products is Wool, appearing in 36.2% of items.

How Products Break Down

47Products

  • Synthetic

    <30% natural fibre · 3 products

    6.4%

  • Blend

    30–85% natural fibre · 22 products

    46.8%

  • Natural

    85–100% natural fibre · 22 products

    46.8%

Most Common Fibres (% of products containing)

Wool
36.2%
Cotton
25.5%
Polyester
23.4%
Polyamide
21.3%
Elastane
12.8%

Where to buy (and avoid).

Not all categories at COSare equal. Here's where the natural fibres are.

Safe Zones · 70%+ natural

Blazer78% natural · 12 productsJacket75.6% natural · 21 productsCoat70.8% natural · 12 products

What we found.

Across 47 products analyzed, COS averages 74.8% natural fibre content.

8.5% of COS products are majority polyester — that's 4 items made mostly from plastic.

COS blazers are their strongest category at 78% natural fibre (12 products).

Their weakest category: coats at just 70.8% natural (12 products).

Only 44.7% of products (21 items) are 95%+ natural fibre.

All categories ranked by natural fibre percentage
CategoryProductsAvg Natural %
Blazer1278%
Jacket2175.6%
Coat1270.8%

Sample Products

A selection of COS products from our database — from most natural to most synthetic. Click to view on the retailer's site.

OVERSIZED DOUBLE-FACED WOOL COAT100% Natural
OVERSIZED DOUBLE-FACED WOOL COAT
Wool 100%
SUEDE HALF-ZIP BLOUSON JACKET​100% Natural
SUEDE HALF-ZIP BLOUSON JACKET​
Goat Suede 100%
STRUCTURED COLLARLESS WOOL BLAZER100% Natural
STRUCTURED COLLARLESS WOOL BLAZER
Wool 100%
OVERSIZED BOILED-WOOL SHORT JACKET100% Natural
OVERSIZED BOILED-WOOL SHORT JACKET
Wool 100%
HOODED DOUBLE-FACED WOOL JACKET80% Mixed
HOODED DOUBLE-FACED WOOL JACKET
Wool 60%Lyocell 40%
BELTED DOUBLE-FACED WOOL LONG COAT80% Mixed
BELTED DOUBLE-FACED WOOL LONG COAT
Wool 60%Lyocell 40%
SCULPTED DOUBLE-FACED WOOL SHORT COAT80% Mixed
SCULPTED DOUBLE-FACED WOOL SHORT COAT
Wool 60%Lyocell 40%
SCULPTED DOUBLE-FACED WOOL SHORT COAT80% Mixed
SCULPTED DOUBLE-FACED WOOL SHORT COAT
Wool 60%Lyocell 40%
OVERSIZED QUILTED JACKET0% Synthetic
OVERSIZED QUILTED JACKET
Polyester 100%
RIBBED-COLLAR QUILTED COAT0% Synthetic
RIBBED-COLLAR QUILTED COAT
Polyester 100%
TECHNICAL HOODED PARKA JACKET0% Synthetic
TECHNICAL HOODED PARKA JACKET
Polyamide 100%
COLLARED DOUBLE-FACED WOOL JACKET100% Natural
COLLARED DOUBLE-FACED WOOL JACKET
Wool 100%

The verdict.

COS is one of the better options for natural fabrics. With 44.7% of products being nearly all-natural, you have real choices here. Still — always check the label. Not every item is created equal.

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Frequently asked questions.

What is COS clothing made of?

Based on our analysis of 47 COS products, the average garment is 74.8% natural fibre. The most common single fibre is Wool (in 36.2% of products). The remaining material is typically synthetic — polyester, polyamide, or acrylic.

Is COS cotton?

Sometimes — cotton appears in 25.5% of the 47 COS products we analyzed, but it's usually blended with synthetics. Only 44.7% of items are nearly all-natural (95%+ natural fibre), so check the composition before assuming a piece is pure cotton.

Is COS 100% cotton?

Some pieces are. Of the 47 COS products we analyzed, 5 are 100% cotton (or near-pure, 95%+) — that's 10.6% of the catalog. The rest are blends.

How much polyester does COS use?

8.5% of COS products are polyester-heavy, meaning polyester makes up 50% or more of the garment. This is below average for fast fashion retailers.

Is COS mostly synthetic?

8.5% of COS products are polyester-heavy (50%+ polyester). Average natural fibre content is 74.8%, so the rest of the catalog is mostly natural-led.

Does COS use natural fabrics?

44.7% of COS products are nearly all-natural (95%+ natural fibre). A decent portion of their range avoids synthetic fibres entirely.

Is COS sustainable in terms of fabric?

Fabric composition is one factor in sustainability. With an average of 74.8% natural fibre, COS is better than many competitors on this measure. Natural fibres generally biodegrade and shed fewer microplastics than synthetics.

Methodology: We analyzed 47 COSproduct pages, extracting the fabric composition listed by the retailer. Products are categorized by name keywords. Natural fibre percentage is the sum of all natural fibres (cotton, linen, silk, wool, viscose, lyocell, etc.) in each product's composition. Data is refreshed monthly.

Use this data.

The Thread Report is openly licensed. Cite it, download it, query it directly — just link back to the source page.

Last updated
License
Free to cite with attribution
Raw dataset (JSON)
info.tryfibr.app/cos.json ↓
Computed stats (JSON)
/api/thread-report/cos

Suggested citation

Fibr Thread Report — COS, 2026-06-12. tryfibr.app/thread-report/cos

Related reports.

COS Jacket21 products, 75.6% naturalCOS Coat12 products, 70.8% naturalCOS Blazer12 products, 78% naturalPolyester at COSIn 23.4% of productsCotton at COSIn 25.5% of productsElastane at COSIn 12.8% of productsCOS vs Abercrombie & Fitch74.8% vs 73.7% naturalCOS vs Acne Studios74.8% vs 83.9% naturalCOS vs AllSaints74.8% vs 54.6% naturalCOS vs Alo Yoga74.8% vs 34.5% natural

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