About The Product
- Composition — Knit with 63% Merino Wool 35% Nylon 2% Lycra Spandex. The fast action wicking pulls moisture away from the skin, so no more sweaty, stinky socks. The soft, breathable merino wool has fast drying, all weather performance that keeps you cool in the summer and warm in the winter.

If you are not sure of the importance of buying products made in the USA, please visit our main site where we make a very compelling case on the virtues of buying American products and in this case the DARN TOUGH Women’s Treeline Hike Trek Sock.
Thank you for buying American.
SUSTAINABILITY
Darn Tough aims to improve the well-being of our community by locally designing and manufacturing the most comfortable, durable, best fitting socks while continuously reducing our environmental impacts.
MATERIALS IN THEIR SOCKS
Every material they use in their socks has been carefully chosen and tested to meet their rigorous durability standards. They currently use natural and synthetic fibers, and only 3 types of fiber per sock. As you’d expect, they are actively investigating and testing new fibers and yarn blends that do not appear in our current products. They’ve prioritized Merino wool throughout their product lines and their goal of producing the most responsibly made product is reflected in their commitment to the success of the Responsible Wool Standard.
MERINO WOOL
Merino wool is the most important and relied upon fiber in their products and accounted for 56% of their yarn consumption by weight last year. For many years they’ve prioritized the use of Merino wool exclusively from sheep that have not been exposed to the practice of mulesing. In early 2019 they made a commitment to support the Responsible Wool Standard (RWS) and shift 100% of their wool supply to RWS-certified Merino wool.
RWS is a voluntary standard with strict guidelines to protect animal welfare and adhere to progressive, sustainable farm and land management practices while maintaining traceability throughout the entire supply chain.
Although the market share for RWS is only estimated at ~1% of global wool production, the number of certified sources has grown substantially over the last couple years. Today, 100% of the wool we procure is RWS-certified.
RECYCLED NYLON
They use REPREVE, a nylon 6 fiber made from pre-consumer industrial waste that would otherwise be landfilled or downcycled. Using REPREVE instead of virgin nylon allows them to offset the use of crude oil, benzene, cyclohexane, and other harmful hydrocarbons that are involved in the production of virgin fiber. In short, using recycled nylon conserves energy and water and reduces greenhouse gas emissions from manufacturing. While they aim to reduce their use of virgin nylon in their products, recycled nylon only accounted for 4% of their nylon consumption last year.
They’re actively working with their suppliers to source more recycled nylon so they can incorporate it across their product lines. To date, nylons generated from pre-consumer waste material have held up well against their durability requirements, but they’d like to find an equally good source of post-consumer recycled nylon or yarns that blend both pre and post-consumer nylon.
SPANDEX/ELASTANE
They use Lycra to provide elasticity, strength, and form-fitting comfort. While spandex accounts for no more than 5% of the fiber used in their finished product, it represented 27% of the raw materials they procured last year. Like conventional nylon, spandex is derived from petroleum and has been important to the performance of their products. Unfortunately, it’s the most difficult material in their fiber mix to replace with a recycled alternative.
When it comes to synthetics, they’re primarily focused on converting virgin nylon and polyester to recycled alternatives. However, they’re also looking for functional, recycled spandex alternatives.