Scientifically approved solution against microplastic pollution from washing.
It reduces fiber shedding and protects your clothes.
It filters the few fibers that do break and doesn’t lose any fibers itself.

It’s a daily reminder to change our buying habits and washing rituals.
180130_SMW_GF_studio_verpackung_stehendhow it works

‘We love that the Guppyfriend not only filters microplastics, but also visualizes, that with each wash, plastic fibers go straight into our oceans.’
– Franziska, Codecheck

‘The Guppyfriend is essential for everyone who cares about the microplastic problem.‘
– Madeleine, Daria Daria, Blogger

‘It works! And it feels really good to be able to do something against microplastics. One more step to becoming an eco-friendly family.’
– Lydia, Guppyfriend User


Microfibers released from washing harm the environment. With each wash, countless plastic fibers from synthetic textiles are making their way from washing machines into rivers and oceans.


STOP! Micro Waste is a nonprofit initiative and is dedicated to raise awareness about the (micro)plastic problem. We aim to explore and initiate great ideas on how to avoid, replace and re-use plastics in every day life and beyond.
More information on



Apart from the zipper the bag is entirely made of Polyamide 6.6. The material is untreated, undyed, and does not contain any additives. It’s pure and can even be used in a medical context.

Recycled material doesn´t work (yet) for this kind of high-tech mesh. But the washing bag is designed in such a way that it can easily be recycled with identical materials at the end of its lifecycle: The whole bag – except the zipper – is made of a single material. Please send your Guppyfriend back at the end of its lifecycle. We´ll reuse and eventually recycle it into new Guppyfriend Washing Bags.

At the moment, we have one standard medium size: 50×74 cm / 19.7×29.1 inches. We’ll offer other sizes in the future. However, the medium-size bag is the most efficient for household use. If you put all your clothes into one large Guppyfriend Washing Bag, they would lose more microfibers by rubbing against each other than if you used two medium sized Guppyfriends Washing Bag.

Unfortunately, most of the PFCs used to impregnate textiles are water-soluble. Consequently, they cannot be filtered out. If possible, always purchase garments without PFCs.

The diameter of a thread is as small as 15μm (μm = microns, 1mm = 1,000 μm). It could theoretically slip through the tiny openings of the Guppyfriend Washing Bag. But it doesn’t. To get through, it would need to poke directly through the mesh. Even if it sticks out, the fiber will be pushed back inside the bag.

As a part of a test program, the Fraunhofer Institute UMSICHT has confirmed that the Guppyfriend Washing Bag not only reliably retains microfibers, but also protects the textiles: Compared to washing without the Guppyfriend Washing Bag, 86% fewer fibers shed from synthetic textiles.

These are the applied washing conditions:

  • 40° C, 99 min, 800 rpm
  • Parallel washing cycles in two identical machines, at least 3 test repetitions for calculating the average of the value measured (mean).
  • Use of synthetic clothing duplicates
  • Filtration of the entire wash water via sieving cascade to 20 microns
  • Drying of the laundry and the screen residue in moderate conditions (30°C, circulating air, cover)
  • Before and after weighing of the textiles and sieve residue to determine the respective textile abrasion

No. Do your laundry as you would do it without the washing bag. For example, a dark-colored shirt inside the bag with whites outside the bag doesn’t make sense. The washing bag doesn’t change that.


If so many fibers do not break in the first place, you will find less of the already tiny microfibers in the corners of the Gupyyfriend washing bag. However, the lifetime of the clothings are extended. Our preferred plastic fibers are those that do not shed at all. Further tests are taking place and a scientific publication on this test series is in the planning stage.

Profits are reinvested in further activities to address the microwaste problem and to avoid single-use plastics.

We already take action to reduce microwaste and hope to extend the scope of the following activities:

  • Inform about microplastic pollution: What can be done to reduce microwaste above and beyond the Guppyfriend Washing Bag?
  • Accelerate re-engineering of textiles: With our countless and on-going washing tests, we receive and share valuable information on how to improve garments to reduce microfiber shedding.
  • Extend our STOP! Plastic Academy lectures on how to avoid microwaste and single-use plastics.
  • Initiate local activities -so called STOP! Stations- to actively reduce (micro)plastic pollution.
  • Research for innovative, pragmatic solutions to reduce microfiber-pollution.

Ackerstraße 113
40233 Düsseldorf


The bag was tested for a period of three years by scientific institutes, universities, retailers and representatives of the outdoor- and fashion industry. These tests serve as a basis for offering the Guppyfriend Washing Bag to their clients as a temporary solution for micro plastic pollution. Mainly, we have tested the Washing Bag with the following scientific and independent institutes:

German Textile Research Institute, DTNW

Fraunhofer Institut UMSICHT

University of California in Santa Barbara as part of a Patagonia research program



The Guppyfriend washing bag reduces fiber loss during washing in two ways:

The Guppyfriend Washing Bag reduces the amount of breaking fibers significantly. The Fraunhofer Institute UMSICHT has confirmed an average amount of a) 79% for partly synthetic clothes, and b) 86% from completely synthetic textiles. The lifetime of the apparel is extended.

Fibrous residues and lints caused by washing are retained by the Guppyfriend Washing Bag and therefore do not pollute the wastewater. The determined fiber retention capacity in all test was above 90%, -mostly close to 100%. Nanoparticles, like production residues, often found on cheaper textiles can not be hold back by the Guppyfriend Washing Bag.



No toxic additives or harmful substances were found on the product.

Even after 50 washing cycles the bag and all seams are intact (ISO 6330). The bag itself does not lose any synthetic fibers (the Guppyfriend Washing Bag can be used for more than the tested 50 washing cycles when applied correctly).

Cleanliness after washing: blood, ketchup and chocolate could be washed out properly, the washing degree towards skin fat and clay is sufficient.

The amount of fibers that are found in the bag depends on washing conditions and clothing itself.



The Guppyfriend significantly reduces breakage of fibers, the fibers that do break are held back reliably, the clothes get clean and -if correctly applied- the Guppyfriend keeps harmful microplastic from entering our rivers and oceans for a long time.

To the test 



The mesh is made out of monofilaments, which are more like sticks than threads, and thus does not release fibers itself. On rare occasions, depending on the mechanical condition of your washing machine, the binding tape around the bag may release a few fibers. The binding tape’s total surface is 0.05m2 and about 100 times smaller than the textiles inside. A washing bag filled with three fleece jackets has an approximate potential fiber-losing surface of 1,9m2 (inside and outside). We are working on alternatives, but we have accepted this compromise at the moment because it extends the overall lifetime of the bag. We constantly test and improve the overall quality of the bag itself and its washing and stability performance.

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  • do not put the bag into the tumble dryer
  • do not rinse under running water
  • wash only clothes of similar colors together in the bag
  • anything sharp may harm the material of the bag
  • do not iron (the crumpled surface is not a problem)
  • use only liquid detergents
  • do not dry in the sun
  • remove coarse dirt and animal hair before washing
  • wash together with other Guppyfriends or with nonsynthetic textiles to avoid an imbalance
  • do not overfill – the clothes need space to move inside the bag

No. When there is no water in the bag, the material becomes statically charged. The electrostatic reaction of round plastic material (in this case the garment and the round nylon monofilament of the Guppyfriend) creates a magnetic field that does exactly what shouldn´t happen to the filter mesh and shed fibers: the small broken fibers are heavily attracted and orientate towards the mesh surface in a 90 degree angle. As a consequence they go straight through the mesh. When there is water in and around the bag the shed fibers lay in various angles on the mesh and don’t puncture it.

Every textile loses microfibers, but it is the synthetic materials (polyester, acrylic, nylon, etc.) that shed the harmful fibers. Most apparel contains synthetic fibers to some degree (unfortunately, sometimes it is not stated on the label).

You can also put pure cotton and wool inside the bag. Textiles from natural materials also lose fibers. The bag reduces fiber breakage, thus protects your garments and reduces wear and tear. You’ll enjoy your clothes  for much longer – another sustainability benefit of the Guppfriend Washing Bag.

No. Depending on what you wash it may take a couple of washes until you find fibers in the upper corners of your bag. (also see: What causes the breaking of microfibers?). Older apparel has the tendency to lose more fibers. The hotter your water, the more likely you’ll lose fibers. And if you only wash soft fabrics, fewer microfibers will break, etc. Whenever you see fibers, take them out, but you can certainly use the washing bag several times before removing the fibers. Make sure that there are no dark microfibers left in the bag when you wash clothes with lighter colors.

Guppyfriend consumers contacted us because they found very few fibers. This is because the microfibers are extremely tiny and barely visible to the naked eye. And that is part of what the bag does (see also: Who tested the bag and what are the results? ): Due to its soft surface and the structure of the filament, fewer fibers actually break.

Certainly, it depends on how you treat it: Use liquid detergent preferably, avoid zippers and any other edges, avoid direct sunlight and don’t wash it above 95°C/ 203°F, and you’ll enjoy the washing bag for many washing cycles. After a few washes, the washing bag doesn’t look new anymore, but still does its job perfectly.

The Guppyfriend Washing Bag was designed to reduce microfiber loss at the source. The structure of the filter surface is optimized to achieve the smoothest surface possible, to protect your garment, to avoid pilling and to reduce fiber loss. (see also: Who tested the bag and what are the results? )

Mechanical forces, one of the main causes of fibers breaking, are reduced by the softness of the filter mesh. The microfibers are extremely tiny and barely visible to the naked eye, and most of the (added) plastic fibers in your textiles are transparent. So, it is hard to detect them, especially in a wet filter bag.

Hence it is perfectly fine when you don’t find microfibers at first. But they will collect over time. You’ll find them mostly in the upper corners or the seam.

But don’t expect to find a lot. It’s the few tiny microfibers that make their way from each washing machine into rivers and oceans that – taken all together – cause harm to oceans and sea life.

It depends on where you live. Most European countries have a landfill ban. In this case you can simply put it into the household trash. In general, it is not a good idea to put it into the recycling cycle (gelber Sack, Wertstofftonne, Grüner Punkt). It may get blown away and eventually end up in the waterways.

In Germany household waste is incinerated to generate electricity and does not end up in landfills. The fumes are in fact being filtered and are 99% non-toxic.

That actually does not depend on the Guppyfriend, but on the washing-instructions and the level of staining of your clothes. But: we wash too hot anyway. The warmer we wash, the more short-lived our clothes will be. For more information about that, check the TEN FOR THE OCEAN Washing Guide.

Just take out the released microfibers on a regular basis. The bag is self-cleaning. Do not rinse the bag under running water.

When washing nothing but the Guppyfriend Washing Bag, certain kinds of washing machines may become unbalanced during the spin cycle. To prevent damage, it automatically stops spinning or reduces the speed. Therefore the laundry will not be dry enough.

To avoid that, please add natural textiles or a second Guppyfriend Washing Bag to your laundry load. It`s also helpful to just fill up the washing bag to the half and to use use liquid detergent preferably to avoid deposits in your laundry.

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The microfibers are so tiny that they would block the filters immediately, literally within seconds. The pressure of the water would also push the fibers through the mesh and the filter would have to be changed constantly. We have a working prototype and there are others working on it too, but it will still take some time until these filters work effectively and are widely available on the market. Until than Guppyfriend will do its job.

Neither washing machines nor wastewater treatment plants can filter microplastic fibers from our clothing satisfactorily. With the wastewater from our households, the tiny microplastic fibers that break during washing get into the wastewater treatment plants.

However, countless particles escape the filter systems and make their way into our waters. According to a study from the University of California at Santa Barbara, an average of 60% – 99% of the microplastic particles can be filtered out of the water.
In Germany, only 20 of about 10,000 wastewater treatment plants have the so-called treatment stage 4, whose primary purpose is to purge our wastewater of medical waste.

Microplastic fibers are exceedingly difficult to filter. Due to their shape and streaming properties, they pass the filter systems much more often than other types of microplastics, such as pellets, microbeads from cosmetics and other plastic fragments.

Even if they can be filtered, the plastic particles end up in the environment via sewage sludge. If the sewage sludge is not incinerated, it is used as fertilizer in the fields. From here, the microplastic particles bound in the sewage sludge make their way into the oceans.

Another problem is collective sewer overflows. They act to relieve the sewage system in rainy conditions. In order to prevent backwater in households in case of heavy rain, the wastewater flows through the sewers untreated.

Incidentally, wastewater from the gullies does not take the detour via a wastewater treatment plant, but gets into our water widely unfiltered. This way, microplastic particles from tires and shoe soles, as well as microplastic fibers that are in the air and in the sewage sludge, pollute our environment.

To sum up: For technical reasons, the filter facilities of the wastewater treatment plants are not sufficient to prevent the pollution of our oceans by microplastics.

What can we do about it? We have to rethink our buying habits, as well as conforming our washing habits.

All garments consisting of synthetic fibers are causing harm. According to the MERMAIDS Life+ project acrylic, nylon and polyester are the major culprits.

However, you’ll find different numbers in different sources. In the end, it doesn’t really matter how many exactly. It’s a lot and we need to prevent them from harming the marine ecosystem.

During the washing process, all clothes lose fibers. The fibers break out of the garment’s structure because of mechanical bending and abrasion stress. These broken fibers are typically from 50 µm up to 15mm long and often not thicker than 10µm. Keep in mind: 1µm = 0.001 mm, or about 0.000039 inch.

Our filter mesh is fine enough to filter out even the smallest of these broken fibers.

For more information on what you can do to prevent microfibers entering the environment, check our TEN FOR THE OCEAN Washing Guide:

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