Durable merino sock specialist whose core products intentionally combine wool with nylon and Lycra/spandex rather than offering 100% natural-fiber socks.
Durable merino sock specialist whose core products intentionally combine wool with nylon and Lycra/spandex rather than offering 100% natural-fiber socks. No brand-wide plastic-free claim is assumed; sewing thread, elastic, linings, closures, finishes, and trims still require product-level confirmation. The score is brand-wide: an excellent 100% natural-fiber item does not make a mixed catalog synthetic-free.
Confirm the exact product page and care label for fiber percentages, sewing thread, elastic, labels, linings, closures, finishes, coatings, and packaging. “100%” normally describes the main fabric unless the brand provides a full component bill of materials.
Merino socks when nylon/elastane blends are acceptable.
Darn Tough states that its wool socks use three yarns: merino wool, nylon, and Lycra spandex. A current dress sock is 46% merino, 49% nylon, and 5% Lycra, so the synthetic share can exceed the wool share.
Full-audit score revised from 62 to 50. Breakdown: 22/40 materials, 8/20 plastic-free construction, 4/15 natural-fiber catalog focus, 3/10 certifications, and 13/15 transparency and independent evidence.
Re-audited 2026-08-02 using the current official catalog and product evidence, then cross-checked against believeintherun.com. Independent sources were used to corroborate composition, certifications, construction, catalog scope, or transparency; unsupported component claims were treated as unknown. Evidence confidence: High.