Fleece is the most successful fabric of the last fifty years. It is warm, it weighs almost nothing, it dries fast, it costs very little, and it made outdoor warmth affordable for people who were never going to buy a wool sweater.
It is also plastic, and it is the single worst microfiber shedder in your wardrobe.
Both of those things are true at once, which is what makes fleece one of the more interesting fabrics to think about. It is not a cynical product. It was invented by people trying to do something good, and one of its inventors deliberately declined to patent it so that everyone could make it. The environmental problem arrived later, discovered largely by the brand that had done most to popularize it.
So here is what fleece actually is, how the types differ, what the shedding research shows, and what to do about a wardrobe that probably already contains three of them.
Related reading: what are synthetic fabrics, sustainable outdoor clothing, our fashion collection, how we rate brands
Fleece At A Glance
- Fleece is almost always polyester. Despite the name, it has nothing to do with sheep.
- It is a knit fabric that has been brushed, raising a pile that traps air. The air is what keeps you warm.
- The main types: polar, micro, sherpa, blizzard, and coral or plush, plus cotton fleece, which is a different thing entirely.
- It sheds more microfibers than any other common fabric, and older garments shed more than new ones.
- Recycled fleece is better on feedstock and identical on shedding.
- If you already own fleece, keep it. Replacing functional clothing is worse than wearing it.
What Fleece Actually Is
Fleece is a knitted fabric with a napped surface. That is the whole definition, and the napping is the important part.
The fabric is knitted from polyester yarn, then run through machines with fine wire brushes that pull individual fibers out of the yarn loops, raising a soft pile on one or both sides. That pile traps air, and trapped air is what insulates you. The same principle keeps birds warm.
Because polyester is hydrophobic, fleece absorbs almost no water. It stays warm when damp, dries quickly, and weighs a fraction of an equivalent wool garment. Those are real advantages, and they are why fleece took over.
The name is misleading. A fleece, properly, is the wool coat of a sheep. The fabric borrowed the word because it mimics the effect, not because it contains any. If you have ever wondered whether fleece is a natural fiber, that confusion is entirely the naming's fault.
Where It Came From
Worth knowing, because it complicates the usual story.
Fleece was developed in 1979 by Malden Mills, a Massachusetts textile company, working with input from Patagonia. The result was originally sold as Synchilla and later as Polartec. It was a deliberate attempt to build a wool alternative that was lighter, warmer for its weight, and did not lose its insulation when wet.
Malden Mills' owner, Aaron Feuerstein, chose not to patent the fabric, which allowed it to spread across the industry within a few years. That decision is why fleece is everywhere and cheap, and it is a remarkable piece of corporate behavior.
In 1993, Patagonia introduced fleece made from recycled plastic bottles, among the first mainstream garments made from post-consumer recycled material. For roughly two decades, fleece was held up as one of the environmental success stories of the apparel industry.
Then, in 2016, research commissioned by Patagonia itself found the problem.
The Microfiber Problem
This is the part that matters most, and the numbers are specific.
Researchers at the University of California, Santa Barbara tested synthetic jackets in domestic washing machines. A single fleece jacket shed on the order of 1.7 grams of microfibers per wash. Older, lower-quality jackets shed roughly twice as much as new, well-made ones. Top-loading machines produced substantially more shedding than front-loaders, by a factor of several times.
Those fibers are too fine for most wastewater treatment to capture reliably. A meaningful share passes through into rivers and oceans, and much of what is captured ends up in sludge that is spread on farmland.
Why fleece specifically is the worst offender: the napping process that makes it soft works by deliberately loosening fibers from the yarn structure. A fabric engineered to have a loose, raised, fuzzy surface is a fabric engineered to shed. Tightly woven polyester sheds far less. The softness and the shedding are the same property.
It gets worse as the garment ages, which inverts the usual sustainability advice. With most clothing, longer use is unambiguously better. With fleece, longer use is still better overall, but the shedding rate climbs.
Recycled Fleece: Better, But Not Solved
Recycled polyester fleece, usually made from PET bottles, is a real improvement in one specific respect: it avoids new petroleum extraction and diverts material from waste streams.
What it does not do is change the shedding. A recycled fleece jacket sheds the same microfibers as a virgin one, because it is the same polymer with the same napped construction.
There is also a wrinkle worth knowing about. Bottles can be recycled into bottles repeatedly. Turning a bottle into fleece takes it out of that loop permanently, because the resulting garment cannot be recycled again in any meaningful volume. It is a step down rather than a circle, which we covered in more detail in our circular economy guide.
Our position: if you need fleece, recycled is the better version. It is not a solution to the fabric's core problem, and brands that present it as one are overselling.
The Types Of Fleece, Explained
Polar fleece. The original and still the most common. Mid-weight, brushed on both sides, warm without much bulk. This is what most fleece jackets and pullovers are made from.
Microfleece. Thinner and lighter, brushed on one or both sides. Used for base layers, linings, and lightweight pullovers. The practical difference from polar fleece is simply weight and warmth, not construction.
Sherpa fleece. Made to imitate the look of shearling, with a bumpy, curly pile on one side and a smooth face on the other. Common as a lining in jackets and in blankets. Despite the name, no sheep involved.
Blizzard fleece. A lighter, more economical mid-weight fleece, widely used for blankets and promotional goods.
Coral fleece and plush fleece. Higher, denser pile, very soft, very fluffy. Common in blankets and loungewear. Also the heaviest shedders in the family, because the pile is longest and loosest.
French terry and sweatshirt fleece. These are usually cotton, and they are a completely different product. See below.
Wool fleece. The original meaning of the word, still used for boiled wool and wool pile fabrics. A natural fiber, and not what most fleece garments are made from.
Is Fleece Cotton? What Is Cotton Fleece?
Two of the most common questions, and the answer is more useful than you might expect.
Standard fleece is not cotton. It is polyester, or occasionally a polyester blend with a small amount of spandex.
But cotton fleece does exist, and more people should know about it. It is a knit cotton fabric with a brushed inner face, and it is what a good sweatshirt is made from. You will also see it called French terry, which technically refers to a looped rather than brushed inner surface, though the terms get used loosely.
Why it matters: cotton fleece gives you the soft brushed hand and much of the comfort with no microplastic shedding, and it is compostable at end of life. The trade-offs are that it is heavier, absorbs water rather than repelling it, dries slowly, and is not as warm for its weight.
Which to choose: cotton fleece for indoor warmth, loungewear, sweatshirts, and casual layering, which is most of what people actually use fleece for. Polyester fleece for cold, wet, active outdoor use where drying speed and warmth-when-damp are safety-relevant.
Most fleece in most wardrobes is doing the first job in a fabric designed for the second.
Natural Alternatives Worth Knowing
Wool, and specifically merino, is the direct competitor fleece was invented to replace. It insulates when damp, resists odor without any chemical treatment, regulates temperature in both directions, biodegrades, and lasts decades. It is heavier, slower to dry, more expensive, and requires more care. Look for certification addressing mulesing, such as ZQ or the Responsible Wool Standard.
Boiled wool and wool pile give you a fleece-like texture in a natural fiber. Warm, dense, and long-lived.
Cotton fleece and French terry, as above.
Hemp fleece, usually a hemp and organic cotton blend. Durable, breathable, and softens considerably with washing.
Alpaca, which is warmer than wool for its weight, naturally hypoallergenic for many people, and produced with a lighter grazing footprint.
If You Already Own Fleece, Keep It
This is the most important practical advice on the page, and it runs against what a sustainability article is expected to say.
Do not throw out functional fleece. The environmental cost of the garment has already been paid, and replacing it with a new wool sweater means paying a fresh manufacturing cost for no benefit. A fleece you wear for fifteen years is a far better outcome than a fleece replaced by something greener after two.
What to do instead:
Wash it much less. Fleece rarely needs washing. Air it, spot clean it, and wash only when actually dirty. Every wash you skip is shedding avoided, and this is by far the highest-impact change available.
Use a filter bag or in-machine filter. Purpose-made laundry bags capture a substantial share of released fibers. Some newer machines include filters, and several jurisdictions are moving toward requiring them.
Wash cold, on gentle, with a full load. Heat, agitation, and loose loads all increase fiber loss. Front-loading machines shed considerably less than top-loaders.
Skip fabric softener, which coats fibers and accelerates breakdown.
Do not tumble dry. Heat damages the pile and dryer lint is largely microfiber. Fleece air dries in a couple of hours anyway.
Repair rather than replace. Fleece patches easily and zippers are replaceable.
Buy your next one in wool or cotton fleece, if the job allows it. That is the decision point, not the one you already made.
Why Fleece Pills, And What "Anti-Pill" Means
Pilling happens when loose surface fibers tangle into small balls. Fleece is prone to it precisely because its surface is deliberately loosened.
Anti-pill fleece has been treated or constructed to resist this, usually through a finishing process that removes the loosest fibers and stabilizes the surface. It does help, and it also means less shedding early on, since many of the fibers that would have come off have already been removed.
How to reduce pilling: wash inside out, wash cold on gentle, avoid fabric softener, skip the dryer, and do not wash fleece with abrasive fabrics like denim or towels.
Pilling is cosmetic, not structural. A pilled fleece is still perfectly warm, and a fabric shaver restores the appearance in minutes.
Rated Brands With Fleece Products
Three brands in our marketplace carry fleece pieces. All have been through our rating process, and nobody pays for placement.
Tentree
The accessible end of our range, working across organic cotton, TENCEL lyocell, and recycled materials. If you want a fleece piece and recycled content is the priority, this is where to look, with the honest caveat from earlier in this article: recycled polyester fleece solves the feedstock question and not the shedding one.
Worth knowing: materials vary considerably across their range, so check the composition on the specific product rather than assuming it applies to the whole line.
Passion Lilie
A Fair Trade Federation member working in organic cotton, designed in New Orleans and handmade in small batches by artisans in India. Their approach across the range favors natural fibers, and they run a resale program returning up to 75% of retail value in credit.
BrunnaCo
Artisan-made pieces with a distinct aesthetic, and worth browsing if you want something with more character than a standard pullover.
Fleece FAQs
What is fleece made of? Almost always polyester, frequently recycled polyester from plastic bottles. It is knitted and then brushed to raise a soft pile that traps air.
Is fleece polyester? Yes, in nearly all cases. Some fleece includes a small percentage of spandex for stretch, and some is blended with cotton or rayon.
Is fleece cotton? What is cotton fleece? Standard fleece is not cotton. Cotton fleece is a separate fabric, a knit cotton with a brushed inner face, which is what most sweatshirts are made from. It does not shed microplastics and it composts, but it is heavier and slower to dry.
Is fleece a natural fabric? No. The name comes from the wool coat of a sheep, which it imitates, but the fabric itself is synthetic.
What is the difference between microfleece and fleece? Weight. Microfleece is thinner and lighter, used for base layers and linings. Polar fleece is the standard mid-weight. The construction is the same.
What is sherpa fleece? A fleece made to resemble shearling, with a curly, bumpy pile on one side. Common as jacket lining and in blankets. Despite the name, it contains no wool.
What is polar fleece? The original and most common type: a mid-weight polyester fleece brushed on both sides. What most fleece jackets are made from.
Does fleece shed microplastics? More than any other common fabric. Research has measured on the order of 1.7 grams of microfibers per wash from a single jacket, with older garments shedding roughly twice as much as new ones.
Is recycled fleece better? Better on raw materials, since it avoids new petroleum and diverts bottles from waste. Identical on shedding. It is also a downcycling step, because the resulting garment cannot be recycled again.
What is anti-pill fleece? Fleece treated or constructed to resist the small fiber balls that form on the surface. It works, and it also means slightly less shedding, because the loosest fibers have already been removed in finishing.
Should I stop wearing fleece? No. Keep what you own and wash it much less, ideally in a filter bag. Make the change on your next purchase rather than by discarding a functional garment.
Final Thoughts
Fleece is a good invention with a problem nobody anticipated for two decades, which is a more sympathetic story than most fabrics get. It was designed to replace wool with something lighter and cheaper, its inventor gave it away rather than patenting it, and the company that popularized it funded the research that exposed its worst property.
What that leaves you with is a practical question rather than a moral one. If you need warmth that survives being soaked on a mountain, fleece or a synthetic insulation is still the right tool, and you should buy one good one and keep it for fifteen years. If you need something warm to wear around the house, which is what most fleece is actually doing, then cotton fleece or wool will do the job without putting plastic in the water every wash.
And whatever you own now, wash it less. That single habit does more than any purchase on this page.
Shop rated natural fiber knitwear and layers in the Shifting Gaia marketplace. Every brand independently evaluated, no paid placements, ever.
Editor's note: Published August 2026. We update our materials guides as research and production standards develop.
