Fashion brands spend millions on sustainability marketing. They publish glossy reports, launch "conscious" collections, and plaster green labels on hangtags. But what does the actual product data say?
Fibr has analysed 17,365+ products across six major retailers, measuring actual fabric composition from product listings. No surveys, no self-reporting, no marketing — just data. Here's how brands really rank.
The Rankings: Brands by Natural Fibre Content
| Brand | Products Analysed | Avg Natural Fibre % | 100% Natural Products | Polyester-Heavy Products |
|---|---|---|---|---|
| Bershka | 9,339 | 62.7% | 45.7% | 25.6% |
| Zara | 5,226 | 60.6% | 43.4% | 28.1% |
| Mango | 2,246 | 59.3% | 40.0% | 25.6% |
| Reformation | 399 | 57.0% | 52.9% | 5.3% |
Some results are surprising. Some are not. Let's break down what the data actually means.
Brand-by-Brand Analysis
Bershka — The Unexpected Leader
Bershka — a brand most people associate with cheap fast fashion — actually leads in average natural fibre content. How? Volume in cotton-heavy categories. Bershka sells enormous quantities of jeans (98.7% natural) and T-shirts (87.1% natural), which pull the average up.
That said, a quarter of Bershka products are still polyester-heavy. The brand isn't making a conscious choice to favour natural fibres — it just happens to sell a lot of denim and cotton basics. Their synthetic items are as synthetic as anyone else's.
Zara — Category Dependent
Zara's 60.6% average hides massive variation by category:
The takeaway: Zara is excellent for basics (jeans, tees, shirts) and terrible for outerwear and activewear. Shop Zara by category, not by brand loyalty. A Zara cotton T-shirt is a good buy; a Zara hoodie is 80% plastic.
Mango — Consistent but Average
Mango sits at 59.3% average natural fibre with 40% of products being 100% natural. These numbers are reasonable but unremarkable. Mango's "Committed" collection markets itself as the sustainable option, but our analysis suggests the overall product range is solidly middle-of-the-pack. With 25.6% of products being polyester-heavy, there's plenty of synthetic in the mix.
Reformation — Marketing vs Reality
Reformation is the brand most associated with sustainable fashion. Its positioning, pricing, and marketing all centre on being the ethical choice. The data tells a more nuanced story.
At 57.0% average natural fibre, Reformation actually scores below Bershka, Zara, and matches Mango. That's a striking finding for a brand that charges premium prices specifically for sustainability.
However, context matters. Reformation has the highest percentage of 100% natural products at 52.9% — more than half its range is fully natural. And critically, only 5.3% of products are polyester-heavy, far below the 25-28% at other brands.
What this means: Reformation avoids the worst synthetic products better than anyone. But it uses a lot of blended fabrics (viscose, TENCEL, recycled materials) that pull the average natural-fibre percentage down. Whether that matters to you depends on whether you prioritise pure natural fibres or low synthetic content.
Aritzia — Small Sample, Big Numbers
Aritzia showed 92.7% average natural fibre in our analysis, but from a limited sample size. This number should be treated with caution — it likely reflects specific product categories rather than the full range. Worth watching as we expand our data, but not yet comparable to the larger samples above.
What the Rankings Actually Tell Us
1. No Brand Is Consistently Good
Every brand in our analysis has polyester-heavy products. The difference is in proportion and where synthetics show up. Even the "best" brand still has a quarter of its range dominated by plastic fabrics.
2. Category Matters More Than Brand
A Bershka cotton T-shirt and a Reformation cotton T-shirt are both cotton T-shirts. Jeans are natural fibre regardless of brand. The biggest wins come from avoiding synthetic-heavy categories (outerwear, activewear, dresses) or being very selective within them.
3. Sustainability Marketing Doesn't Equal Natural Fibres
Reformation charges 3-5x more than Bershka partly based on sustainability positioning, yet has a lower average natural-fibre content. "Sustainable" can mean recycled polyester, low-water processes, or ethical manufacturing — none of which change what the fabric feels like against your skin.
4. The Industry Is Still Majority Synthetic
Even the best-performing brand in our analysis (Bershka at 62.7%) means that on average, more than a third of every garment is synthetic. The fashion industry has a long way to go.
How to Shop Smarter with This Data
- Buy basics from high-performing categories. Jeans, T-shirts, and shirts are reliably natural fibre across most brands.
- Be most careful with dresses, outerwear, and activewear. These are where polyester dominates.
- Don't pay a premium for marketing. A $25 Zara cotton shirt has the same fabric quality as a similar product from a "sustainable" brand at $80. Pay more for better cut, construction, and ethical manufacturing — not just a green label.
- Check every product individually. Brand averages are useful for general direction, but within any brand, products range from 100% cotton to 100% polyester.
- Use our guide to finding natural fibre clothing for specific shopping strategies.