Innovation in DNA

We make our products from a range of carefully selected materials. We seek to be innovative and aim to source 100% of our materials from sustainable sources by 2022. This includes organic and better cotton as well as recycled and innovative materials. Learn more about the individual materials we use below.


Underworks is proud that it currently sources 100% of its cotton from sustainable cotton sources. By 2021, in under a year, we managed to transition away from conventional cotton altogether and assured that all of our cotton was Better Cotton certified organic and thus preferred more sustainable cotton, according to the Preferred Fibre and Materials Market Report. Both these types of cotton use significantly less water, energy and chemicals than conventional cotton. Underworks is a pioneer in this area, as the global average for companies sourcing sustainable cotton in 2021 was only 25%.

Find out more about our 2030 cotton transition.


Bamboo is and wild and abundantly available plant species that grows all over China. It requires much less water than most other fibre species and when organically grown like ours, it requires no pesticides and fertilisers at all. Besides that, bamboo has natural anti-bacterial, anti-fungal and moisture wicking properties, while its hollow structure allows the bamboo material to be warm yet breathable.

Find out more about our bamboo process.


Wool is one of the most popular animal fibres and it has a long history in apparel and textiles. It is known for its naturally anti-bacterial and anti-odour properties as well as its breathability and temperature regulation traits. This super soft material is 100% natural and biodegradable, and its durability and quality make it a very sustainable material that is made to last. Our wool comes either from sheep (labelled wool) and merino sheep (labelled merino wool). Merino wool is known for its ultra-softness, light weight, and superior wrinkle resistance as well as its high breathability and technical performance. We regularly use merino wool in our thermal base layers, as customers regard this as one for the most comfortable materials to wear directly on the skin to keep them warm, but thermally regulated. We source our wool responsibly from farms in China and work closely with our supplier so that animal welfare standards are maintained.

Recycled Polyester

Polyester is a high-performing, durable, shrinking and wrinkle resistant and lightweight material that dries quickly and is stain resistant. Besides that, it has high-colour fastness meaning that is takes overall less time, energy and resources to dye polyester yarns. With all these key performance attributes it is unsurprising that it is the most used fibre in the world. However, there is a downside to the material as it is a petrochemical polymer, meaning that is it made from the non-renewable resource oil. On a mission to reduce our global dependence on virgin petrochemical resources we have started experimenting with recycled polyester. By using recycled polyester, we divert plastic going into landfill, including plastic bottles ocean plastic waste and polyester fibre offcuts and scraps.

Recycled Nylon

Like polyester, nylon is a versatile synthetic fibre of petrochemical origin. Nylon is used in a variety of apparel applications and has gained wide fame in the hosiery and sportswear space. The name nylon represents a family of synthetics polymers, which means they are comprised of a long chain of carbon molecules, called monomers, and is also known as polyamide. One of the more desirable attributes of this material are its elasticity and stretchability. Nylon is super strong, abrasion resistant and easy to wash, and it is quite unyielding to damage. These combined attributes make it an excellent complimentary fibre in socks. By sourcing recycled nylon, for example from discarded fishnets or other types of nylon waste materials, we divert waste from landfill and oceans, while still utilizing the great benefits of this resource. As part of our commitment to preferred fibres we seek to source recycled nylon options where possible for our products containing nylon. These can be either from pre-consumer or of post-consumer origin.

Recycled Wool

All materials have an environmental cost, and we know that grazing sheep require vast arrays of land and wool production requires chemicals, water, and energy. Recycled wool has very similar benefits as regular wool, however, has a much lower environmental impact, because it skips various production steps. By using recycled wool, we divert waste from landfill and give wool a secondary life, without compromising on quality. Wool is one of the most advanced recycled fibres globally as it has been successfully recycled in regions in Italy and India for hundreds of years. Woollen jumpers or other wool products can be collected, sorted on colour composition, shredded, and spun into yarns.


Modal is a silky soft, durable, and stretchy fibre made from sustainably sourced beech trees. Modal is a type of viscose that uses wood pulp as input material and blends this with a solvent. This solvent softens the material, and after purification the wood pulp is converted into cellulosic fibres which can be spun into yarns. It is an eco-conscious material that is frequently used in underwear, socks and jersey t-shirts. Modal uses natural fibres as its input that come from FSC certified sources to make sure it does not harvest wood from protected and endangered forests. Modal processes use less chemicals and energy than regular viscose manufacturing.


Cashmere is known as a very soft, elegant and comfortable material. Cashmere wool comes from the downy undercoat of cashmere goats, which originate from the mountains of Mongolia, Nepal and China. The fine but strong wool has superior moisture wicking properties, and the material causes no scratch feeling whatsoever. Just like our other wool products we make sure the animals providing our cashmere are treated with dignity and animal welfare standards are maintained.


We use a variety of other materials amongst which viscose, polyester, nylon and elastane. We know that some of these materials use non-renewable resources and a significant amount of energy, hence why we are constantly innovating and looking into recycled or renewable alternatives.

With viscose, we are looking at novel closed-loop processing methods, that reuse up to 90% of the chemicals and water, such as Tencel lyocell. We also ensure that the wood used as input for the viscose process comes from sustainable sources, such as FSC certified forests. To take it one step further, we are investigating regenerated cellulosic fibres that use recycled fibre scraps rather than wood as their input materials, such as Tencel Refibra. Unfortunately, when it comes to synthetic fibres, we struggle to always achieve the same great quality you are expecting from us when using recycled fibres, and therefore we opt for durability and quality over recycled inputs. We however always seek to ensure the materials are procured from the most sustainable sources, are ethically made and encourage our customers to recycle their socks where possible. Yet one of our key goals on our roadmap to 2030 is to slowly phase out virgin non-renewable materials like polyester and nylon and replace these with 100% recycled alternatives, such as recycled polyester and recycled nylon. One of the biggest hurdles in the sock business is to find a viable alternative to elastane also known as Lycra or Spandex, the material that gives your socks that perfect stretch and keeps them up all day long.

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