Vegan
How we decideSynthetic fleece is vegan. Malden Mills and Patagonia developed it in the late 1970s as a polyester answer to wool, and recycled PET bottles now feed much of the supply. One garment can release over a million microplastic fibers in a single wash.
- Origin
- Synthetic — typically made from polyester, sometimes recycled polyester (rPET). Developed in the late 1970s as a synthetic alternative to wool for outdoor insulation.
- Common Uses
- Outdoor jackets, base layers, blankets, pet beds, children's clothing.
- Durability
- Good. Lightweight, warm, and durable. Maintains insulating properties when wet (unlike wool).
Environmental Impact
High Environmental ImpactOne of the primary contributors to microplastic ocean pollution. A single fleece garment can release over 1 million microplastic fibers per wash. Patagonia funded early research into this problem and now includes a microplastic warning on its fleece products.
Editorial Notes
Fleece was developed by Malden Mills (now Polartec) and Patagonia in the late 1970s. Recycled fleece from PET bottles is now standard in the outdoor industry. Despite being vegan and warm, the microplastic problem is significant. Polartec High Efficiency (PHE) fleece has a tighter knit that sheds fewer fibers — worth seeking out.
In depth
How synthetic fleece is made
Synthetic fleece is a knitted polyester fabric. Production begins with polyethylene terephthalate (PET), the same polymer used for plastic drink bottles. The polymer is melted and extruded through fine nozzles into continuous filament yarn. Knitting turns that yarn into a base fabric. That fabric passes through napping machines, where rotating wire brushes raise the surface fibers into a soft pile, and is then sheared to an even height. The raised pile traps air, which is what gives fleece its insulating ability at a low weight.
Recycled fleece follows the same steps but starts with post-consumer PET bottles. The bottles are sorted, cleaned, shredded into flakes, melted, and re-extruded into yarn. The fabric was developed in the late 1970s by Malden Mills, the company now operating as Polartec. Patagonia was an early adopter that helped bring it to outdoor apparel. Malden Mills did not patent the fabric. That decision allowed fleece to spread across the entire apparel industry and become one of the most common insulating materials in the world.
How fleece compares to wool
Fleece was designed as a synthetic substitute for wool, and the two remain the most common choices for insulating mid layers. Fleece is light for the warmth it provides. The fabric dries quickly, retains much of its insulating ability when damp, and is machine washable without special care. Fleece is also generally cheaper than wool and does not itch, which is part of why it dominates children's outdoor clothing.
Wool holds advantages elsewhere. It naturally resists odor, while polyester fleece retains body odor and tends to need more frequent washing. Wool is also naturally flame resistant, whereas polyester melts when exposed to high heat. That difference matters around campfires and stoves. From a vegan standpoint the comparison is one-sided: fleece involves no animal inputs, while wool production raises welfare concerns, including mulesing in some regions and the routine slaughter of sheep whose wool yield declines. Environmentally, the picture is mixed. Wool biodegrades but carries high land-use and methane footprints, while fleece persists in the environment and sheds microplastics.
The microplastic problem and how to limit it
Fleece's loose, brushed structure makes it one of the heaviest-shedding fabrics in the laundry. Each wash releases large numbers of polyester microfibers, and wastewater treatment plants capture only part of them. The remainder passes into rivers and oceans, where such fibers have been found in marine organisms, drinking water, and sea salt. Patagonia funded some of the early research quantifying this shedding and has since publicized the issue to its customers.
Shedding can be reduced but not eliminated. Washing fleece less often, using cold water and shorter cycles, and running full loads all lower fiber release. Washing bags such as the Guppyfriend and external washing-machine filters capture a meaningful share of fibers before they enter wastewater. Some research indicates that front-loading machines cause less shedding than top-loaders. Tighter-knit and specially engineered low-shed fleece constructions shed less than traditional high-pile fleece, so fabric choice at purchase matters as much as laundry habits afterward.
Reading labels: "fleece" is not always synthetic
On garment labels, synthetic fleece appears simply as polyester, typically "100% polyester" or a polyester-elastane blend. Terms such as polar fleece and microfleece, and brand names like Polartec, all indicate synthetic fabric. Recycled versions are usually flagged as "recycled polyester" or rPET, sometimes with a bottle count on the marketing tag.
The word "fleece" itself requires caution, because it originally refers to the shorn coat of a sheep. Wool fleece garments exist, and some "fleece-lined" boots, slippers, and jackets are lined with shearling. Shearling is a sheepskin with the wool still attached, an animal-derived material. Sherpa fleece, despite its wool-like appearance, is almost always polyester or acrylic. Only the fiber content label is reliable. If the label lists only polyester, acrylic, or other synthetic fibers, the garment contains no animal material and is vegan.
Frequently asked questions
Is fleece vegan?
Yes, synthetic fleece is vegan. The fabric is made entirely from polyester, a plastic-derived fiber, with no animal inputs. The only caution is the word "fleece" itself, which can also describe sheep's wool or shearling linings. Check the fiber content label to confirm the garment is fully synthetic.
Is fleece made from sheep?
No. Synthetic fleece is made from polyester, which comes from petroleum or recycled plastic bottles. The fabric borrowed its name from a sheep's fleece, because it was designed to imitate wool. No animal fibers are involved.
Is fleece as warm as wool?
For its weight, fleece provides warmth broadly comparable to wool. It dries much faster. It also retains insulating ability when damp and tolerates machine washing without special care. Wool's advantages lie elsewhere, mainly in natural odor resistance and flame resistance.
Does fleece release microplastics?
Yes. Fleece is among the heaviest-shedding fabrics in the wash, releasing polyester microfibers that partly pass through wastewater treatment into rivers and oceans. Shedding can be reduced with cold, infrequent washes, washing bags such as the Guppyfriend, machine filters, and tighter-knit fleece constructions.
What is recycled fleece made from?
Most recycled fleece is made from post-consumer PET plastic bottles, which are cleaned, shredded, melted, and spun into polyester yarn. The fiber is chemically the same polyester as virgin fleece and sheds microfibers in the same way. It avoids new petroleum extraction. Labels usually read "recycled polyester" or rPET.
How do I stop my fleece from shedding microfibers?
You cannot stop it entirely, but you can cut it down. Wash fleece less often, in cold water, on short cycles, and in full loads. A microfiber washing bag or an external washing-machine filter captures much of what does shed, and tighter-knit fleeces shed less than fluffy high-pile ones.