Buyer Guide · 02
Sock Yarn Guide: Cotton vs Merino vs Bamboo vs Recycled
What each fiber actually delivers on the foot, what it costs, and which certifications to ask for — so you can spec a sock that matches your shelf price.
TL;DR — the short answer
- Combed cotton is the volume baseline: soft, breathable, cost-efficient — the default for everyday and kids' programs.
- Mercerized cotton adds a silk-like luster for dress socks without synthetic shine.
- Merino wool (RWS) is the premium outdoor fiber: warm when wet, naturally odor-resistant.
- Bamboo viscose markets well and feels cool, but relies on nylon reinforcement for durability.
- Recycled polyester (GRS) is the sustainability story that actually holds up on a bill of materials.
Fiber-by-fiber comparison
| Fiber | Hand feel | Moisture | Durability | Certification available | Typical use |
|---|---|---|---|---|---|
| Combed cotton | Soft, matte | High absorption | Good | OEKO-TEX®; GOTS (organic) | Everyday, kids, athletic blends |
| Mercerized cotton | Silk-like luster | High | Good | OEKO-TEX® | Dress & business socks |
| Merino wool | Fine, non-itch (≤19.5μ) | Warm when wet | Moderate (blended) | RWS; OEKO-TEX® | Hiking, thermal, winter |
| Bamboo viscose | Cool, slippery-soft | Very high | Needs nylon | OEKO-TEX®; FSC (pulp source) | Ladies' fashion, summer lines |
| Recycled polyester | Crisp, technical | Wicking | High | GRS | Sports, sublimation printing |
| Nylon | — | Low | Very high | OEKO-TEX®; GRS (recycled) | Reinforcement, compression |
| Elastane (spandex) | — | — | — | OEKO-TEX® | Stretch & fit, 2–5% of blend |
Which blend for which program
Real-world blends we run weekly — these are starting points, not limits:
Everyday & retail basics
80% combed cotton / 17% nylon / 3% elastane. The volume driver: soft, sturdy, price-sharp. Takes knitted logos cleanly at 144N–168N.
Athletic & running
Cotton or recycled-poly face with terry cushioning, nylon reinforcement at heel/toe, arch compression zone. Wicking beats absorption for race-day use — lean recycled poly.
Outdoor & thermal
40–70% merino (RWS) blended with nylon for wear life. Full cushion. Merino below 19.5 micron keeps it non-itch against skin.
Dress & business
Mercerized cotton, fine rib, matte finish with a subtle luster. Gauge 168N–200N for a refined hand; zero synthetic shine.
Questions to ask any supplier about yarn
- "Is the cotton combed or carded?" Carded cotton pills faster and feels rougher — combed is the baseline for export quality.
- "Which micron is the merino?" Above ~21.5μ risks the itchy feel that drives returns on hiking lines.
- "Is the certification transaction-level?" GOTS/RWS/GRS claims should come with transaction certificates naming your shipment — a logo on a website is not a certificate.
- "What is the elastane content?" Under 2% and socks bag at the ankle; over 5% and they bind. 2–5% is the working window.
- "Do you test colorfastness per lot?" We test ISO 105-X12/X16 to Grade 4+ on every yarn and dye lot — ask for the lab report with your sample.