Your fleece is shedding plastic. So is mine. That's not a scare line, it's just what fleece is: polyester, spun fine and brushed fuzzy, and fine fuzzy fibers break loose. If you own synthetic clothing, you are putting microfibers into the world, and no purchase or habit gets you to zero.
Here's the part that usually gets left out of that story: where the shedding actually happens. It's mostly not on the trail. The number 1 shedding event in a fleece's life is laundry day, the washing machine and, even more than people realize, the dryer. Which is genuinely good news, because laundry day is the one part of your gear's life you completely control. This post covers what the research actually shows about microfibers from clothing, and then the short list of laundry habits that measurably cut shedding. No fearmongering, no purity tests. A prevention guide, not an alarm.
What the research actually says
Synthetic textiles are one of the largest sources of microplastics in the environment. A widely cited 2017 report from the International Union for Conservation of Nature estimated that about 35% of the primary microplastics entering the oceans come from synthetic textiles, largely via laundering, making it the single biggest source category in their model, ahead of tire wear. The full IUCN report is public if you want the methodology.
The anchor study on laundering is Napper and Thompson's 2016 work in Marine Pollution Bulletin, which washed polyester, polyester-cotton, and acrylic fabrics under controlled conditions and counted what came out. Their estimate for a typical 6 kg wash load: roughly 138,000 fibres from polyester-cotton, about 496,000 from polyester, and over 700,000 from acrylic. The Napper and Thompson study is worth reading for the caveats too: fiber counts vary a lot with fabric construction, wash conditions, and how you count, so treat these as order-of-magnitude figures, not gospel.
Two other findings matter for what follows. Hartline and colleagues' 2016 study in Environmental Science & Technology washed fleece jackets in real home machines and found that top-load washers released around 7 times the microfiber mass of front-load machines, and that mechanically aged garments shed more than new ones. That's the Hartline et al. paper. And Pirc and colleagues, washing a new polyester fleece through 10 consecutive cycles, found that shedding started high, dropped over the first few washes, then stabilized. The same Pirc et al. study measured something else that shaped this whole post: tumble drying that fleece released roughly 3.5 times more fibers than washing it did.
So the shape of the problem is clear. It's real, it's large in aggregate, and for any individual garment it's concentrated in a specific, repeatable event: the wash-and-dry cycle. That's where the leverage is.
A reframe, from the founder's chair
I'll speak for myself here. Some amount of microplastic shedding is baked into recreating outside. Shoe soles abrade on granite. Tent floors wear against dirt. Pack fabric fuzzes where the straps rub. You cannot walk into the woods in modern gear and leave zero synthetic material behind, and I've watched people tie themselves in knots over this in a way that mostly just keeps them indoors. That misses the point twice: the trail isn't where most of the shedding happens, and staying home doesn't stop your laundry.
The move, I think, is the same one we apply to pack weight: find the few changes that are low effort and high impact, make them, and then go hiking without carrying the guilt. For a fleece, almost all of those changes happen at home, in the roughly 51 weeks a year you're not on trail. Wear the thing hard outside. Be deliberate on laundry day. That's being respectful to wild places as best we can while still actually enjoying them, which is the entire reason we protect them.
The laundry-day playbook
1. Wash it less
The cheapest intervention is subtraction. Every wash is a shedding event, and fleece rarely needs the full treatment: it doesn't sit against your skin the way a baselayer does. Air it out overnight, spot-clean with a damp cloth, and save machine washes for when it's actually dirty. Fewer washes means fewer fibers and a longer-lived garment, which is the same logic behind everything in our gear maintenance guide: the gentlest care schedule that keeps gear functional is usually the right one.
2. Wash it colder, quicker, and fuller
A University of Leeds study published in 2020 compared cold, 30 minute cycles against standard 40°C, 85 minute cycles and found the cold-quick cycles released significantly fewer microfibres and less dye, with the garments also holding their color and shape longer. The Leeds summary of the study has the details. Full loads help too, since a packed drum means less free tumbling and less water per garment; that one, along with cold water and liquid detergent, is on the National Park Service's own list of laundry microfiber tips. On detergent, the evidence is mixed: De Falco and colleagues found powder detergents drove more shedding than liquids, presumably from the extra abrasion of the granules, while Pirc's team saw no significant detergent effect at all. Liquid is the safer bet, and it's zero extra effort. The De Falco et al. 2018 study covers the detergent comparison.
If you're ever choosing a machine: Hartline's 7-to-1 result makes the front-loader the clear pick, and it's the same advice we already give for washing down gear, where top-loader agitators are hard on baffles. One machine choice, 2 benefits.
3. Use a wash bag
A microfiber wash bag is a fine-mesh bag you zip your synthetics into before they go in the drum. It works 2 ways: the bag reduces the mechanical abrasion that breaks fibers in the first place, and it catches most of the fibers that break anyway, so you can bin them instead of sending them down the drain. The best-known is the Guppyfriend, which Patagonia sells in its own store alongside its fleece lines. Testing commissioned from the Fraunhofer Institute UMSICHT, reported by Guppyfriend and repeated on Patagonia's product page, found on average 86% fewer fibers breaking off fully synthetic garments washed in the bag, 79% for partly synthetic ones, with the broken fibers collecting in the bag's corners. Worth knowing: independent testing of fiber-catching devices, like Napper's 2020 device comparison in Science of the Total Environment, has generally measured smaller reductions than manufacturers report, and results vary a lot between devices and test setups. The honest summary is that wash bags help meaningfully, and no single percentage should be taken as a promise.
4. Or filter the whole machine
External washing machine filters plumb into the discharge hose and strain fibers out of every load, no bag required. The established options are the Filtrol, PlanetCare, and the Lint LUV-R, all still on the market as of 2026, with manufacturer capture claims in the 80s and 90s percent and independent tests, again, finding real but generally lower and more variable numbers (the PIRG overview of filter testing is a readable summary). They cost noticeably more than a wash bag and need periodic cleaning, but they cover every load automatically, including the ones you forget to think about. Regulators are moving this direction too: France passed a requirement that new washing machines sold from January 2025 include a microfiber filter, the first country to do so, though the technical rules needed to actually enforce it were still unresolved as of this writing, so treat it as a signal of direction rather than a done deal. Some manufacturers have started offering built-in or add-on filters ahead of wider mandates, so if you're washer shopping, it's now a spec worth asking about. Background on the French law is in this summary of the mandate and its status.
5. Skip the dryer. Really.
If you only change one habit after reading this, make it this one. Pirc's fleece study found tumble drying released about 3.5 times more fibers than the wash itself, and a 2022 study by Tao and colleagues in Environmental Science & Technology Letters measured a household tumble dryer emitting on the order of 400,000 to 560,000 microfibers in 15 minutes of use, vented straight to outdoor air. Dryers, per that work, can out-shed washing machines for the same load of clothing. Here's the Tao et al. dryer study.
Hang drying is the rare fix with no downside. Synthetics dry fast on a rack or a line, usually overnight. You shed dramatically fewer fibers, you skip the heat and tumbling that age the garment, and a fleece that lasts years longer is itself a microplastics win, because the biggest plastic footprint of any garment is the replacement you didn't need to buy. Less shedding, longer-lasting gear, less waste. That's the whole win-win, and it costs a drying rack.
6. Expect the first-wash spike
New synthetic garments shed the most in their first few washes, as loose fibers from manufacturing work free, then settle to a lower baseline. That's the Pirc result above, and other groups have seen the same decline. So give a brand-new fleece its first 2 or 3 washes inside a wash bag or a filtered machine if you can, and know that the curve bends in your favor from there, at least until the garment is genuinely worn out, when Hartline's data suggests shedding climbs again. A threadbare 15-year-old fleece that's actively pilling apart has earned retirement, ideally through a textile recycling program rather than another season of heavy shedding.
Where hard goods fit in this
Textiles are the big shedders because they're made of thousands of fine fibers designed to flex. Hard goods sit at the other end of the spectrum, but material choice still matters, and it's the same thinking that shaped our own products. We molded the NOBO Bottle in unpigmented HDPE with a silicone-isolated cap seal because the research on bottles points to the cap interface and UV-degraded material as the dominant shedding pathways, and HDPE holds up better than the alternatives on both. The full reasoning, studies included, is in our post on how the NOBO is designed to reduce microplastic exposure. Same philosophy as this post: you can't get to zero, so design around the pathways that actually dominate.
Honest limits, and the point
Individual laundry habits will not solve microfiber pollution. The aggregate problem is a textiles-industry and wastewater-infrastructure problem, and the meaningful long-term fixes, fiber engineering, filtration standards, and rules like France's, happen upstream of your utility room. It's also worth saying that the health effects of microplastic exposure are still being worked out, and this post has deliberately made an environmental argument, not a medical one.
But "individuals can't solve it" is not the same as "individual choices are pointless." Your fleece will shed a certain amount over its life. Whether most of that ends up down the drain and in the air, or caught in a bag and binned, is decided by maybe 10 minutes of habit change: wash less, wash cold and full in a front-loader if you've got one, bag or filter the synthetics, and hang the thing to dry. Then put the fleece on and go outside, which was always the point. We started this company to make gear worth taking into wild places, and that story, for what it's worth, is in Made in California. Take care of the places. Don't let the guilt keep you home.
