Thread Report
COS: June 2026
COS is one of the stronger performers in our dataset, averaging 76.9% natural fibre across 675 products we analyzed. Only 9.6% of products are polyester-heavy — relatively low compared to many retailers. On the bright side, 53% of COS products are made almost entirely from natural fibres (95%+). The most common fibre across COS products is Cotton, appearing in 43.6% of items.
Natural Fibre Distribution
- 9.3%
Synthetic
<30% natural fibre · 63 products
- 35.1%
Blend
30–85% natural fibre · 237 products
- 55.6%
Natural
85–100% natural fibre · 375 products
Top Fibres by Frequency
Fabric by Category — June 2026
| Category | Products | Avg Natural % |
|---|---|---|
| Sweater | 15 | 99% |
| Jeans | 53 | 97.9% |
| T-Shirt | 48 | 96.7% |
| Shirt | 64 | 86.2% |
| Shorts | 35 | 85.8% |
| Pants | 55 | 82.9% |
| Coat | 52 | 76.4% |
| Jacket | 50 | 68.4% |
| Dress | 168 | 67.3% |
| Skirt | 41 | 64.2% |
| Blazer | 36 | 63.8% |
COS in Other Months
Monthly Thread Reports
Get reports like this in your inbox.
We analyze thousands of products every month. Be the first to see new Thread Reports — fabric data nobody else publishes.
No spam. Unsubscribe in one click.
Frequently Asked Questions
What is COS clothing made of?
Based on our analysis of 675 COS products, the average garment is 76.9% natural fibre. The most common single fibre is Cotton (in 43.6% of products). The remaining material is typically synthetic — polyester, polyamide, or acrylic.
Is COS cotton?
Sometimes — cotton appears in 43.6% of the 675 COS products we analyzed, but it's usually blended with synthetics. Only 53% of items are nearly all-natural (95%+ natural fibre), so check the composition before assuming a piece is pure cotton.
Is COS 100% cotton?
Effectively no. We didn't find any COS products that are 100% cotton (or near-pure, 95%+) in our database. Cotton at COS is almost always blended with elastane, polyester, or other fibres.
How much polyester does COS use?
9.6% 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?
9.6% of COS products are polyester-heavy (50%+ polyester). Average natural fibre content is 76.9%, so the rest of the catalog is mostly natural-led.
Does COS use natural fabrics?
53% 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 76.9% natural fibre, COS is better than many competitors on this measure. Natural fibres generally biodegrade and shed fewer microplastics than synthetics.
Related reports.
Stop buying plastic by accident.
Fibr shows you what every garment is actually made of before you buy it. Green means natural fibre. Red means plastic.
Add to Chrome — It's freeFree forever. No account, no data collected, nothing to lose.