Part 3: What Fabric Structure Reveals About Microfiber Shedding
If you have been following along, you will know this is the third part of my series on microfiber pollution. In Part 1 I explained the motivation behind this project: understanding how textile construction affects fiber loss during washing. Part 2 walked through the experimental setup, including fabric types, washing conditions, and the role of the Guppyfriend bag.
Now, in Part 3, I am sharing the results: what actually happened when seven different fabrics, tested in three swatches each for a total of 21 samples, went through multiple wash cycles and what this tells us about shedding behavior.
To recap briefly, I tested a mix of knit and woven fabrics, including both plush (e.g., chenille, velveteen) and smooth (e.g., jersey, plain-woven cotton) textures. Some were washed directly in the machine, while others were enclosed in a Guppyfriend bag, designed to capture microfibers. After each cycle, a few swatches were removed to track changes in shedding over time.
First Wash = Most Shedding
The first wash cycle produced the highest fiber release, no matter the method. This is because all 21 swatches were still present, maximizing surface area for fibers to break away. By the second and third cycles, fewer swatches remained, and shedding naturally declined. Less fabric = fewer fibers. This “front-loaded shedding” pattern has also been observed in controlled studies of microfiber release during laundering [1].
Importantly, fibers were not just found in the wash water, many also stuck to the washing machine drum or, in the case of the Guppyfriend bag, to the towels inside. This highlights an important point: shedding is not just about what escapes into wastewater, but also about where fibers end up.
Knit vs. Woven: The Shedding Showdown
The results showed that knits shed more than wovens on average, due to their looser, looped structure that allows fibers to slip free. This aligns with scientific studies showing that knitted fabrics shed significantly more than woven fabrics under the same conditions [2].
However, structure was not the only factor. Texture amplified the effect: plush wovens like velveteen and chenille, along with denim, shed heavily, sometimes rivaling or even surpassing knits.
Plush Fabrics: The Worst Offenders
Across all tests, plush, pile, and bulky fabrics shed the most. Their fuzzy surfaces feel soft because they are made up of loose fiber ends, but those same fibers are easily pulled free during washing. In contrast, smooth fabrics like jersey and plain-woven cotton shed much less. This reflects broader research showing that pile or “hairy” fabrics (like fleece, velveteen, and chenille) are consistently high-shedding textiles [3].
The key takeaway: plush, fuzzy fabrics are the biggest shedders, regardless of whether they are knit or woven.
In Context: How My Findings Compare with Scientific Consensus
Most peer-reviewed studies conclude that knits shed more microfibers than wovens, because of their looser, looped structure that allows fibers to slip free more easily. For example, one study found that polyester knits released more than twice as many fibers as polyester wovens under the same washing conditions [4].
My results aligned with this overall pattern: knits shed more on average. But I also found that texture amplified shedding behavior. Plush wovens such as velveteen and chenille released large amounts of fibers, sometimes rivaling or even surpassing knits.
The nuance is important:
Structure matters → knits > wovens on average.
Texture can override structure → plush, fuzzy fabrics shed the most, regardless of whether they are knit or woven.
This combination of findings shows why it is not enough to focus only on knit vs. woven construction. In everyday laundry, what you feel, smooth vs. fuzzy texture, is often the best predictor of shedding.
Containment Is not a Cure-All
The Guppyfriend bag, a popular microfiber-catching laundry solution, did reduce the number of fibers found in the wash water, which is promising. But it was not a total fix: the fibers did not disappear, they just stuck to the towels inside the bag. Independent research has reached similar conclusions, noting that while containment reduces fibers in wastewater, it often shifts them onto other textiles in the load [1].
In other words, the problem did not go away; it changed form. This reveals a critical nuance in microfiber containment strategies: capturing is not the same as eliminating. Independent research has reached similar conclusions, noting that while containment reduces fibers in wastewater, it often shifts them onto other textiles in the load [1].
Capturing is not the same as eliminating
What This Means for Everyday Washing
Washing a smooth jersey T-shirt releases fewer fibers than washing a plush fabric like chenille or velveteen.
The difference is less about knit vs. woven, and more about surface texture.
Smooth fabrics hold fibers tightly, while plush or fuzzy fabrics are full of loose ends that break away, especially in the first few washes.
Containment tools like the Guppyfriend bag are helpful, but they are not silver bullets. To really tackle microfiber pollution, we need smarter textiles, better laundry habits, and more sustainable production methods.
Sources:
[1] Marine Pollution Bulletin, 2019
[4] PMC, 2022
