Sweaters should be wool. That’s the entire point of the garment — a knitted wool layer for warmth. But Fibr’s data tells a different story: Bershka sweaters average just 38.2% natural fibre. The majority of what’s sold as a “sweater” in fast fashion is acrylic — a petroleum-based plastic that mimics wool’s appearance but shares none of its properties.
That makes sweaters one of the worst categories in fashion for natural fibre content — worse than dresses, worse than jackets, worse than pants. Here’s what you should be wearing instead.
Why Acrylic Dominates (and Why It Shouldn’t)
Acrylic has taken over knitwear for one reason: cost. Acrylic yarn costs a fraction of wool, and it can be dyed to look like natural knitwear on a hanger. Consumers often don’t check labels on sweaters — they see a knitted texture and assume it’s wool or at least a wool blend.
But acrylic fails at everything a sweater is supposed to do:
- Insulation. Acrylic insulates poorly compared to wool, especially when damp. Wool traps air in its crimped fibres; acrylic compresses flat.
- Breathability. Acrylic traps heat and moisture against your body. You overheat indoors, then get cold when the sweat chills. Wool regulates temperature naturally.
- Durability. Acrylic pills heavily within a few wears. Those little balls of fuzz on your sweater? That’s the acrylic fibres breaking down — and each one is a microplastic.
- Odour. Acrylic absorbs and holds body odour. Wool is naturally antimicrobial and resists odour for days between washes.
- Shape retention. Acrylic stretches out and doesn’t bounce back. A wool sweater returns to shape after wear.
An acrylic sweater is a plastic garment that looks like knitwear for approximately two wears before it pills, stretches, and starts smelling.
The Best Natural Sweater Fabrics
1. Merino Wool
Merino is the best all-round sweater fabric. The fibres are finer than standard wool (under 24 microns), which means it’s soft against skin without the itch. Key advantages:
- Excellent warmth-to-weight ratio
- Naturally odour-resistant — can be worn multiple days
- Breathable and moisture-wicking
- Less pilling than other wools
- Machine-washable in many modern blends
Price range: Mid-range. More expensive than acrylic, far less than cashmere. A quality merino sweater costs $80-150 and lasts years.
2. Lambswool
Lambswool is the first shearing from a young sheep — naturally softer than adult wool. It’s a classic sweater material: warm, durable, and affordable relative to merino or cashmere.
Best for: Traditional crew neck and V-neck sweaters. Slightly coarser than merino but more durable. Great value for natural knitwear.
3. Cashmere
The luxury option. Cashmere is lighter and softer than sheep’s wool, with exceptional warmth. A quality cashmere sweater is one of the finest garments you can own.
Caveats:
- Quality varies wildly. Cheap cashmere (under $100) uses short, low-grade fibres that pill quickly. Good cashmere uses long-fibre, high-ply yarn.
- Less durable than wool. Cashmere is softer but weaker. It pills more than merino and requires more careful handling.
- Environmental concerns. Cashmere goat farming has driven overgrazing in Mongolia. Buy less, buy better.
Price range: $150-500+ for quality. Avoid “cashmere” sweaters under $80 — the fibre quality won’t be there.
4. Cotton Knit
For lighter sweaters and warmer climates, cotton knit is a solid natural option. It’s breathable, soft, machine-washable, and affordable.
Limitations: Cotton doesn’t insulate as well as wool. It’s a transitional or indoor sweater fabric, not a cold-weather layer. It can also stretch out over time without the elasticity of wool.
Best for: Spring/autumn layers, office wear, warmer climates where wool is too heavy.
5. Alpaca
Warmer than wool, hypoallergenic, and silky-smooth. Alpaca is an underrated sweater fibre that performs exceptionally well:
- No lanolin, so it’s less likely to cause allergic reactions
- Lightweight but extremely warm
- Minimal pilling compared to wool or cashmere
- Available in a wide range of natural colours without dyeing
Price range: Similar to good merino, $80-200. Less common in mainstream retail but increasingly available from specialist brands.
How to Spot Acrylic Before Buying
- Check the label. If it says acrylic, modacrylic, or polyester — it’s plastic. Period.
- Be sceptical of “wool blend.” A label that says “wool blend” might be 20% wool, 80% acrylic. The percentages tell the real story.
- “Knit” doesn’t mean wool. Acrylic can be knitted into any pattern. The knit texture tells you nothing about the material.
- Price is a signal. A “wool” sweater for $25 almost certainly isn’t all wool. Genuine wool sweaters start around $50-80 at minimum for basic options.
The Sweater Decision Matrix
| Fabric | Warmth | Softness | Durability | Price |
|---|---|---|---|---|
| Merino wool | Excellent | Very soft | Very good | $$ |
| Lambswool | Excellent | Soft | Excellent | $$ |
| Cashmere | Excellent | Exceptional | Moderate | $$$$ |
| Cotton knit | Moderate | Soft | Good | $ |
| Alpaca | Exceptional | Very soft | Very good | $$$ |
| Acrylic | Poor | Artificial | Poor (pills) | $ |
Every natural option outperforms acrylic on warmth, breathability, and longevity. The only thing acrylic wins on is upfront price — and when you factor in how quickly it degrades, even that advantage is questionable.