Thorlos® - Proprietary Protection Yarns Explained - Visuals & Text

Thorlos Sock Product Philosophy:

Managing the Interface between the Foot and Shoe

Driven by its mission to enhance quality of life by providing unique sock products that protect and keep feet healthy, THOR•LO® continues to search for new combinations of technologies, fibers, constructions, and yarns that improve their consumers' activity specific performance and the added value of the experience of more enjoyment of their activities.

THOR•LO believes its sport specific sock products are a key component of all active footwear because the sock product protects the foot from the shoe itself. No matter what new breathtaking shoe technology is offered, there still remains this interface... the "front line of attack" on the foot.

The "closed" environment of a shoe is hostile to the foot. High humidity, elevated temperatures, pressure points and (shear) friction "hot spots" all contribute to foot discomfort and can lead to painful results like blisters or callus build up. In addition to these immediate consequences, the foot will adapt over long periods of time to the repetitive stresses it receives from being trapped in this "artificial" environment. The long-term results can be debilitating, i.e., hammertoes, bunions and accelerated breakdown of the protective layer of "fat" tissue under the ball and heel of the foot, eventually leading to permanent loss of mobility. Prevention of the negative consequences of simply wearing shoes has become THOR•LO's constant mantra.

By elevating the importance of a sock product, THOR•LO has taken a different approach to sock design than most hosiery companies. Pressure dissipation, shear protection, and moisture management are the key design criteria for creating the Thorlos experience. In all cases, the protection value of the sock product comes before aesthetic considerations.

For this reason, THOR•LO currently identifies only a small variety of fibers, blends, and yarns that currently meet our high standards for moisture management, shear protection, and pressure dissipation. Following is an explanation of the three main categories of yarns that currently, meet our standards: acrylics, modified polyesters and wool blends. You will notice that cotton, the most popular textile fiber is absent from this list. This natural fiber works well when it is exposed to air and can "breathe". When trapped in the closed environment of the shoe, however, cotton absorbs moisture, causing its coefficient of friction to increase and the terry loops of the sock product to collapse. The same is true of 100% wool fibers. When this happens, the sock product loses its ability to protect against shearing and impact pressure, leading to blisters. THOR•LO learned this early on, and has proven this through years of scientific research and field testing of all possible fibers, blends, and yarns.

Acrylic Yarns

Acrylic fibers and yarns (specifically, long-staple worsted spun) have been the main choice for THOR•LO'S sock designers from its earliest beginnings in the 1970's. Even today, no other fiber has as many desirable qualities as acrylic [for Thorlos sports specific sock product].

Acrylics are generally characterized by having high "loft" and resilience. When spun to the Thorlos' "exclusive" specifications (THOR•LON®), it is durable, soft, and remains resilient even when "wet" with perspiration. This greatly reduces the effect of shear forces (lateral, sliding motion) on the foot. Acrylic does not absorb perspiration into the fiber like cotton (and 100% wool) but "wicks" moisture along the surface of the fiber, thus aiding evaporation and keeping the foot noticeably drier.

By not absorbing the bacteria-laden perspiration into the fiber cell walls, acrylics are naturally more "sterile" and easier to clean without the use of harsh bleaches, which will eventually destroy elastomeric yarns (spandex) used in the tops of most athletic sock products today. Acrylics are also hypoallergenic and do not elicit the itchy, allergic responses common with products made from most 100% wool yarns.

All Acrylics are not created equal. By working closely with our exclusive suppliers, THOR•LO further customizes the inherent properties of acrylic fibers to produce the very best yarn possible for all Thorlos sock products.

  1. THOR•LON® Acrylic

    THOR•LON Fiber cross section

    THOR•LON trademark acrylic yarns are spun to THOR·LO's exclusive specifications and have been specifically developed for our "exclusive" Thorlos constructions. "Trapped" perspiration in the shoe environment tends to "flatten" or crush down common acrylic yarns, but THOR•LON acrylics are especially spun to maintain both softness and resilience, which maximizes foot comfort, blister protection and product durability.


Highly Modified Polyesters

DuPont introduced these truly unique fibers in the mid 1980's. DuPont was able to produce an innovative category of desirable fiber characteristics by extruding polyester into hollow core and "clover leaf" cross-sections. They realized that the shape of the synthetic fiber contributes as much to its inherent qualities as does its raw ingredients.


    This is a fiber with a unique four-channeled cross section that produces a soft, cotton-like yarn with excellent moisture movement properties. Moisture movement is enhanced by the wicking action the channels of the fiber. Thorlos with THOR•WICK® COOL provide outstanding blister protection and excellent moisture management during high perspiration activities and in hot climates.

Wool Blends

One of the things that sets THOR•LO apart from other sock manufacturers is the knowledge and use of blended yarns. In outdoor activities such as, hiking, skiing, and mountain climbing, the sock product must be able to keep the foot warm as well as deal with the moisture produced during vigorous activity. Since these two characteristics are difficult to achieve with one fiber, it is best to use a blended yarn consisting of two or more fibers.

  1. Wool/Silk (65/35)

    Wool/Silk Fiber cross section

    Imported "wild" [raw] silk is blended 65% with soft and resilient shrink-treated wool to produce incredibly warm performance in OUTDOOR and SKI Thorlos. Silk enhances the moisture absorbency, insulating properties, strength, and pilling resistance of natural 100% wool. This produces superior comfort, warmth and durability, which is understood by the most discriminating consumers as well worth the added expense.

  2. Wool/Polyester/Silk (50/30/20)

    This yarn blend was conceived for all season performance. The addition of 30% polyester improves moisture dissipation and extends the recommended comfort zone to warmer climate conditions than our completely natural wool/silk blend.

  3. Wool/ THOR•LON acrylic (50/50)

    Wool/THOR•LON Fiber

    This performance fiber blend is intended for active cold climate use, and is designed for improved blister protection and comfort without sacrificing the significant insulating properties of natural wool. The addition of 50% THOR•LON acrylic improves loft and resiliency (protection), and greatly enhances the moisture management qualities that 100% wool yarns alone cannot provide for our OUTDOOR Thorlos consumers.



Nylon is one of the oldest of the man-made fibers. It is exceptionally strong, resilient and abrasion-resistant. Nylon endows Thorlos with strength and durability that not only aids in their protective characteristics, but also helps them last longer. It is also instrumental in helping to provide the stretch and recovery characteristics that allow for precision in sizing and revitalization of the Thorlos' terry fabric after washing.