Vegan clothing beyond leather: what actually replaces wool, down, silk and cashmere

Almost nothing sold as a wool, down, silk or cashmere replacement is actually plant based. Open the label on a vegan wool coat, a vegan down jacket or a vegan silk scarf and the fibre content is almost always polyester, nylon or acrylic: fossil fuel feedstocks, spun into fibre, that shed microplastic every time they are washed. That is the fact the category leaves out of its own marketing, and it is not on its own a reason to keep buying wool or down. Leaving an animal industry does not mean leaving petrochemicals behind, and a genuinely good vegan wardrobe has to solve for both costs at once, not pretend the second one does not exist.

Leather has its own guide, on how vegan leather is made, and this one does not repeat it. What follows is everything else: the fibres that keep you warm, the ones that used to line your grandfather's jacket, and the ones on a suit you would never think to check.

A wool fibre is not just fluffy. It has a natural crimp, a three dimensional wave caused by two cell types in its cortex that expand at different rates when they absorb moisture, and that crimp holds thousands of tiny air pockets against the skin. Air is a poor conductor of heat, so those pockets are the insulation. The fibre's outer cuticle is covered in overlapping scales with a waxy coating, which sheds light rain, and the fibre itself can absorb up to 30 to 35 percent of its own dry weight in moisture before it feels wet to the touch. That combination, insulating structure plus a high moisture buffer, is why wool keeps working in weather that flattens synthetic fill.

The welfare case against wool centres on mulesing: cutting strips of skin from a lamb's rear, usually without pain relief, to create scar tissue that resists flystrike in the wrinkled skin bred into merino sheep. Victoria and Tasmania have passed laws requiring pain relief for the procedure, and in 2026 the New South Wales Parliament introduced a bill to do the same, per reporting from The Land. The RSPCA has tracked what it calls twenty years of Australian industry promises to phase mulesing out entirely, none of them yet kept. Beyond the procedure itself, welfare groups also document live export of Australian sheep to Middle Eastern markets by sea, and the fact that a wool sheep's productive life still ends at the same slaughterhouse as a meat sheep's.

The Responsible Wool Standard, run by the nonprofit Textile Exchange since 2014, audits farms for animal welfare and land management and now commands a real price signal: non mulesed and RWS certified fleece is trading at roughly 100 cents per kilogram clean above conventional wool in the 2026 Australian clip, according to Wool Producers Australia. It is worth being honest about what that premium buys: better treatment during the sheep's life, not an exemption from slaughter at the end of it.

Down is not feathers. It is the fluffy plumage from a duck or goose's underside, and its job is loft: the amount of air a given weight of fill can trap, which is why sleeping bags and jackets are rated in fill power, a measure of the cubic inches one ounce of down occupies. High fill power down, 800 and up, is prized precisely because so little of it does so much insulating work per gram.

Two welfare problems sit underneath that number. Live plucking, pulling feathers from a bird that is still alive rather than waiting for slaughter or a natural molt, remains documented in supply chains that certify otherwise: an undercover investigation by PETA found workers live plucking geese at farms supplying companies that also sourced Responsible Down Standard certified down, exploiting the standard's own rule that RDS certified companies may still buy and sell live plucked feathers from uncertified parent farms. Down also overlaps with foie gras production, since force fed ducks and geese raised for liver are the same birds whose down often enters the supply chain as a byproduct. The Responsible Down Standard, managed by Textile Exchange, verifies the chain from chick to finished product and audits certified sites annually, and bars live plucking and force feeding along that chain, but FOUR PAWS notes it does not trace or certify the parent farms where live plucking risk is highest, which is the gap the PETA findings exploit.

Synthetic insulation, of which PrimaLoft is the best known trade name, is built from fine polyester fibres engineered to mimic down's cluster structure. The company says its Gold insulation matches the warmth to weight of roughly 550 fill power down, and multiple outdoor gear reviewers cite internal PrimaLoft testing claiming the material keeps around 96 percent of its warmth when saturated. The mechanism is straightforward: synthetic fibres do not absorb water into their structure the way a down plume does, so they keep their loft, and their insulating air pockets, when a down jacket's would collapse into a sodden clump. Down still wins on pure warmth per gram in dry conditions, which is why ultralight backpackers keep buying it. For anything that might get properly wet, a good synthetic fill has closed most of that gap and eliminated the live plucking risk entirely.

A silk cocoon is one continuous filament, sometimes over a kilometre long, spun by a silkworm to protect itself while it metamorphoses into a moth. Harvesting that filament intact requires killing the pupa before it chews its way out and breaks the strand, usually by boiling or steaming the cocoon within about 15 minutes of it being finished. That is the whole objection to conventional silk: the fibre's value depends on the animal never emerging.

Ahimsa silk, also called peace silk, waits roughly ten extra days for the moth to hatch out on its own before the cocoon is processed, which breaks the single filament into shorter lengths that must be spun together like cotton, giving peace silk a rougher hand and a higher price. It is a real welfare improvement on the specific act of boiling a live pupa, and it is not the full story: peace silk still depends on farming, confining and, in practice, losing large numbers of silkworms in captivity, since only a fraction are allowed to complete their lifecycle as breeding stock. Anyone buying it as a clean conscience purchase should know that caveat.

The material alternatives split into two generations. Cupro, spun from cotton linter waste, and Tencel modal, from wood pulp, both replicate silk's drape and sheen well enough that they are now standard linings in mid range fashion. The newer generation is fermentation derived structural protein, engineered to mimic spider silk's molecular structure rather than a silkworm's. Spiber, a Japanese company, now produces its Brewed Protein fibre at hundreds of metric tons a year and has supplied Burberry, Goldwin and The North Face, and Kraig Biocraft Laboratories reported a single production cycle yielding nearly 2.5 metric tons of engineered silk protein between May and June 2026. It is real and it is scaling, but it remains a specialty material at a specialty price, not something you will find on a rack at ordinary retail yet.

Cashmere is the soft undercoat combed or sheared from cashmere goats, and yields only a few ounces of usable fibre per animal each year, which is what makes it expensive and why goat numbers have to be enormous to meet demand. Mongolia alone produces roughly a third of the world's cashmere and now supports about 22 million cashmere goats, and a national survey found 65 percent of the country's grasslands degraded, driven by that goat population and a warming climate, according to NPR's reporting and confirmed by Science. Unlike sheep, goats graze by pulling plants up rather than cropping them, which strips root systems and accelerates desertification. This is the one animal fibre in this guide where the ecological argument stands on its own, independent of the welfare one: overgrazing by an animal raised specifically for fashion is measurably converting steppe into desert. Researchers studying the region believe 90 percent of degraded rangeland could recover naturally within a decade if herding pressure eased, which tells you the damage is a choice being renewed every season, not a fixed cost of the fibre.

There is no plant fibre that fully replicates cashmere's fineness and warmth to weight, which is why most vegan cashmere on the market is acrylic or a acrylic wool blend, itself a plastic. A tightly woven merino free alternative worth knowing about is a heavy Tencel or organic cotton knit brushed for loft, which will not match cashmere's warmth ounce for ounce but avoids both the animal and, mostly, the plastic cost.

This is the honest cost of the default swap. A 2016 study by Imogen Napper and Richard Thompson in Marine Pollution Bulletin found that a single 6 kilogram wash load of synthetic clothing can release more than 700,000 microfibres into wastewater. Follow up research has put the range anywhere from roughly 9 milligrams to over a gram of shed fibre per kilogram of fabric washed, depending heavily on the fabric's construction, with fleece and other mechanically brushed knits shedding several times more than tightly woven fabrics of the same fibre. Wastewater treatment catches most, not all, of that load, and what escapes ends up in rivers, oceans and, increasingly, in the water people drink.

The mitigations are real but partial. A 2020 comparative study of laundry filtration devices found that a Guppyfriend washing bag captured about 54 percent of shed microfibres in test loads, while a Cora Ball, tested independently, has been measured anywhere from 11 to 31 percent depending on the study's method. Front-loading washing machines shed markedly less than top-loading agitator machines, because they use less water and less mechanical abrasion per cycle. Washing synthetics less often, in full loads, on cold, and letting them air dry rather than tumble dry, all reduce shedding, but none of these habits gets you to zero. If a garment is synthetic, some of it is going into the water supply as plastic, and no laundry bag changes that fact, only its size.

Certifications answer different questions and it is worth knowing which. The Responsible Wool Standard and its Responsible Down Standard counterpart verify animal welfare and traceability at the farm level, not chemical safety or dye toxicity. GOTS, the Global Organic Textile Standard, verifies organic fibre content plus environmental and labour practices across the whole supply chain, audited annually. OEKO-TEX Standard 100 tests only the finished product, every thread, button and zipper, for harmful chemical residues, and says nothing about how the fibre was farmed or the animal or worker was treated. A garment can pass one and fail the intent of another.

The word vegan on a tag is a narrower promise than most shoppers assume. It means no animal derived fibre, adhesive or trim was used, full stop. It does not mean biodegradable, it does not mean low carbon, and it very often means polyurethane or PVC, plastics that are themselves persistent pollutants and, per the phrase used across sustainability reporting on vegan leather, are marketed with sustainability language the material itself does not earn.

Animal materials also hide in places a vegan shopper would not think to check on a garment that reads, correctly, as leather free. Tailored jackets are shaped by an internal canvas woven from linen or cotton combined with horsehair, usually from a horse's tail, for its springy resilience. Suit buttons are frequently cut from animal horn, and jacket linings from silk. Down trim shows up on parka hoods long after the jacket body has gone synthetic. Waxed cotton jackets are traditionally finished with a beeswax and paraffin blend. None of these are disclosed the way a leather panel is, because none of them are the headline material, and all of them are worth a second look at a garment's construction details, not just its outer fabric label. For the underlying ingredient verdicts, see the entries on wool, silk, down, cashmere, beeswax and lanolin, the last of which coats most conventional wool even after it is spun.

A 2021 analysis commissioned by Oxfam GB found that if every adult in the UK bought half of their next wardrobe secondhand instead of new, it would prevent roughly 12.5 billion kilograms of carbon dioxide, described as the equivalent of a plane circling the globe more than 17,000 times. Separate research on secondhand consumption found reductions of up to 42 percent in climate impact and up to roughly 53 percent in freshwater related impacts per garment worn, compared with buying new, regardless of what the garment is made from. WRAP's research in the UK has repeatedly found that keeping a garment in active use for longer cuts its carbon, water and waste footprints substantially, which is why wearing what you already own outperforms any material choice.2 years.

That arithmetic holds for wool, down, silk and cashmere exactly as it holds for polyester. A secondhand wool coat has already absorbed the welfare cost of its production, and buying it new does not undo that, while buying it secondhand adds no new demand for mulesed wool and diverts nothing from a landfill. A guide to vegan clothing that only ever points to new synthetic purchases is not being straight about which choice actually wins on both counts. Buy less first, buy used second, and treat the material swaps below as what to reach for only once those two are exhausted.