A Complete Guide to the Materials in Our Socks

Most sock labels tell you almost nothing. You get a list of percentages and no explanation of why any of it is there.

So here's ours, explained properly. Eight materials appear across our range: cotton, polyester, polyurethane, acrylic, nylon, wool, mulberry silk and rayon. This is where each one comes from, and what it's actually doing in the sock on your foot.

Cotton is a natural fibre that grows in fluffy bolls around the seeds of the cotton plant. People have been spinning it for at least 7,000 years — there's evidence of it in the Indus Valley and in ancient Peru.

Most of the world's cotton now comes from India, China, the US, Brazil and Pakistan. After harvest it goes through ginning, which separates the fibres from the seeds. Then it's cleaned, combed (sometimes) and spun into yarn.

In a sock, cotton is the comfort fibre. It breathes. It feels soft straight away, with no break-in period. It also absorbs moisture readily, which is what makes a cotton sock pleasant for ordinary daily wear.

However, because it is so absorbent, cotton holds water rather than moving it along, so a wet cotton sock stays wet. It also has virtually no stretch or recovery of its own. That's why you'll almost never really find it used alone, not helpful for those who tend to get sweaty feet either! — and why a 100% cotton sock is usually a worse sock, not a purer one.

Combed cotton

Combed cotton isn't a different fibre. It's ordinary cotton put through an extra step before spinning. A quality grade, not a material — but it makes a difference you can feel.

Normally cotton is carded: pulled through wire teeth to straighten the fibres and shake out debris. Combing goes further. Finer combs pull out the short, immature fibres, called noils, along with any last bits of leaf and seed. About 15% of the mass gets stripped away. That's why combed cotton costs more. You're paying for what was removed.

What's left is just the long, straight fibres. The yarn comes out smoother, because there are no stubby fibre ends poking out. It's stronger too, since long fibres grip each other over more of their length. It pills less and sheds less lint, for the same reason.

That matters more in socks than in most clothing. Socks get constant friction, hot washes, and your entire body weight pressing them into your skin. Short-fibre yarn gives up under those conditions. Combed cotton holds its surface much longer.

One thing that often gets muddled: staple length is a separate idea. That's how long the fibres are on the plant, and it's what Egyptian and Pima cotton are known for. Combing happens after harvest and can be done to any cotton. Long-staple combed cotton is genuinely the best of both — but the two terms get used interchangeably in marketing, and they shouldn't be.

Tabi socks with Combed cotton (most of our graphic prints):

Chysanthemum print Tabi socks

Bright pink and blue festival socks

White Rainbow numbers Tabi socks

Hemp is a bast fibre, which means it comes from the stalk of the plant rather than the seed head. The plant is Cannabis sativa — the same species as marijuana, and that's the main reason most people have never knowingly worn it.

The difference is simple. Industrial hemp is a separate cultivar, bred over generations for long fibrous stalks instead of flowers. THC content is negligible; the legal limit here and across most of Europe is 0.2% or 0.3%. You could set fire to an entire drawer of hemp socks and feel nothing.

Unfortunately, the association stuck. Hemp cultivation was restricted or banned across much of the twentieth century, and an entire fibre industry simply stopped. Hemp didn't lose on merit. It lost on legislation.

Worth knowing, if you like tabi: in Japan hemp came long before cotton. Asa (麻) was the everyday cloth for centuries. Cotton only became widely grown around the sixteenth century. Before that, silk was for those who could afford it and hemp was for everyone else.

As a fibre, hemp is among the strongest natural options available — and unusually, it stays strong when wet, where a lot of fibres weaken. In a sock that means real resistance at the heel and toe.

It also improves rather than degrades. New hemp feels crisp, slightly dry. Cotton thins and pills over time; hemp does the opposite. The fibre bundles separate with washing and the fabric softens while keeping its structure. A hemp sock is usually better in year three than in week one.

The fibre is hollow and porous, so it breathes and moves moisture, with a slight natural cooling quality. It's also a low-input crop — typically much less water than cotton, dense enough to crowd out weeds without herbicide, few pest problems, and ready to harvest in about four months.

Two honest caveats. You'll often see hemp called naturally antibacterial. There's some research pointing that way, but not enough for me to put it on a label as something you should expect. And “hemp” alone doesn't guarantee a clean product — traditional retting is low-impact, some modern chemical processing isn't. The processing matters as much as the plant.

Pure hemp makes a stiff sock, so we blend it with cotton. Hemp brings strength, breathability and structure; cotton brings the softness you want from the first wear. Both are cellulose fibres, so they dye and wash compatibly. It's an old pairing in Japanese textiles for good reason.

If you wish to explore more in depth about Hemp we have written a more detailed blog post into this underrated fibre!

Polyester is a synthetic fibre spun from petroleum-derived polymers. It was developed in Britain in the 1940s and went on to become one of the defining fabrics of the twentieth century.

It's made, not grown and recently there's a growing resistance to polyester garments because of it. Petrochemicals are reacted into a polymer, melted, and pushed through tiny holes to form filaments. A growing share of textile polyester is now recycled — usually rPET, made from old drinks bottles.

Polyester earns its place in a sock through moisture. It's hydrophobic, so instead of soaking water into the fibre, it moves it along the surface to where it can evaporate. Your foot stays drier. It also holds its shape well, dries fast, resists abrasion, and takes dye brilliantly. If you own a boldly patterned sock, there's likely to be polyester in it.

As it's petroleum-based, and synthetic fabrics shed microplastics in the wash, this is big enough cause for people to dismiss it altogether as a material which is understandable.

Most of our tabi socks will contain a small percentage in but our Invisibles range is 100% cotton:

Invisible white tabi socks

Invisible grey tabi socks

Invisible black tabi socks

In sock-making, polyurethane nearly always means elastane — the stretch fibre you might know as Lycra or Spandex. It can stretch several times its own length and snap back.

It's spun into extremely fine filaments, which are then usually wrapped in cotton or nylon. So the elastane provides the spring while something softer sits against your skin.

Its influence is wildly out of proportion to its percentage. Two to five per cent is all it takes to make a sock grip your arch, stay up your leg, and return to shape after every wear. Without it, socks bag and slide down.

In a tabi sock it does one more job. It keeps the split-toe pocket crisp and properly seated, instead of gaping open.

Acrylic is a synthetic fibre engineered to behave like wool. Soft, lofty, warm, and very light.

It's produced much like polyester, then crimped — a step that adds bulk and gives acrylic that woolly hand-feel.

In socks it delivers warmth and cushioning for a fraction of wool's weight and cost. It's hypoallergenic, which matters if you react to wool. Moths won't touch it, it won't shrink or felt, and it keeps its colour. That combination is why you'll find it in thicker winter and boot socks.

It doesn't breathe as well as a natural fibre, and like all synthetics it sheds microfibres. As part of a blend it does a specific job well.

Nylon is a synthetic polyamide, first sold commercially in 1939 and famous for stockings. For its weight, it's extraordinarily strong.

The strength comes from the drawing process, where the filament is stretched and the molecules line up.

Nylon is the durability fibre. It usually sits in the heel and toe — the two places socks wear through first — and it extends the life of a pair dramatically. It also smooths the finish, helps hold shape, and dries quickly. Very fine nylon is what makes sheer and invisible socks possible at all.

Wool is a natural protein fibre — sheep's fleece, harvested by shearing. Merino comes from Merino sheep and has a finer fibre than standard wool, which is why it feels soft instead of scratchy.

Sheep are shorn once or twice a year. The fleece is scoured to strip out lanolin and dirt, then carded, combed and spun. Each fibre has a natural crimp, which traps air, and most of wool's best qualities come from those tiny pockets of air.

Wool is the best natural fibre for socks, and it isn't a close contest. It insulates in the cold and regulates in the heat. It can hold around 30% of its weight in moisture and still feel dry. It resists odour, so wool socks go longer between washes. And it genuinely stretches — a wool fibre can bend tens of thousands of times without snapping, which is why wool socks keep their shape.

It needs a gentler wash than synthetics, and it isn't vegan. Where we use it, we say so.

Tabi socks containing wool:

Soft wool blend Tabi socks

Mulberry silk comes from the domesticated silkworm Bombyx mori, which eats nothing but mulberry leaves. It's the finest and most even of all silks, and the diet is the reason.

Sericulture started in China more than 4,000 years ago and reached Japan around the third century, where it became central to the textile tradition. The method hasn't really changed. Silkworms are raised on mulberry, and each one spins a single unbroken filament — sometimes over a kilometre long — into a cocoon.

Because Bombyx mori has been bred for this for thousands of years and eats only one thing, its filament is remarkably smooth and uniform. Wild silks like tussah are shorter, coarser and patchier in colour. For knitwear, shorter fibres and cocoon remnants get spun into what's called spun silk. Slightly less lustrous, softer, and better behaved in a sock.

Silk does one thing no other fibre matches. The filament has no surface scales, so there's almost no friction against skin. If you get blisters, or your skin is sensitive, that's worth more than any other single property on this page. It's a protein fibre like wool, so it also regulates temperature and wicks moisture while feeling dry. And it's strong — stronger than steel of the same diameter — which is how a very thin silk sock can still last.

The honest limitations: it's expensive, so it turns up in smaller percentages or in specific styles rather than throughout a range. It has poor recovery, so it needs blending. Sunlight and alkaline detergents weaken it, so silk socks want a gentle wash and a shaded dry. And conventional silk isn't vegan — reeling kills the pupa inside the cocoon. Peace silk, harvested after the moth emerges, is an alternative, though the fibre comes out shorter and duller. Where we use silk, we say which kind.

Silk suits a tabi sock particularly well. The split-toe design puts fabric directly between your toes, and a low-friction fibre in that spot is a functional advantage rather than a luxury.

Rayon is semi-synthetic: plant cellulose, usually wood pulp or bamboo, chemically processed into a spinnable fibre. Neither properly natural nor properly synthetic.

The cellulose is extracted, dissolved into a thick solution, and forced through spinnerets into a chemical bath where it hardens into filaments.

That process is worth knowing about, because bamboo rayon gets marketed as though bamboo's natural properties survive it. They mostly don't. What survives is the cellulose. So if you see an antibacterial claim attached to bamboo rayon, be sceptical.

What rayon does genuinely offer is a lovely hand-feel — smooth, cool, faintly lustrous — plus good absorbency and excellent drape. Lyocell is the same idea made in a closed-loop system that recaptures and reuses its solvent, which makes it the more responsible version.

Tabi socks containing Rayon:

Angora blend dainty floral Tabi socks - has a blend of acrylic, wool, nylon, polyester, polyurethane

Extra small Sakura blossom socks 

No single fibre makes a good sock on its own. There are multiple factors apart from material that makes a good sock such as knit density, toe seam and construction amongst other things. (Read here for the full write down on how to identify an overall good quality sock)

Cotton is comfortable but shapeless. Elastane holds everything in place but is unwearable alone. Nylon is tough and not remotely soft. Wool performs beautifully but needs reinforcing. Silk is unmatched against skin and won't hold a shape by itself.

A good sock is a deliberate combination. Something comfortable against the skin, something durable where it wears through, something with recovery to hold the whole thing together. Materials are only half the story: making your socks last longer also comes down to how you wash and wear them.

Last updated: 7th August 2026