Polyester Deep Dive: Is It Safe, Sustainable, and Replaceable?
Why I Started Researching Polyester
Fabric is at the heart of sewing — without it, we have no garment. But not all fabrics are created equal. Over the last few weeks, partly out of curiosity (and because I thought you might be interested too), I’ve been on a deep dive into polyester — learning what it is, how it’s made, and whether it’s really as bad for us (and the planet) as we’ve all heard.
Polyester is affordable, comfortable, and hard-wearing — which is why it’s my number-one choice for activewear. I love wearing leggings that stretch, wick sweat, and don’t hold moisture when I run. But I couldn’t help asking:
Is polyester harmful to my skin?
Why did we create it in the first place?
And if I stopped using plastic-based fabrics, what are the real alternatives?
A Fabric That Changed the World
The Invention of Polyester
Polyester (from poly, meaning “many,” and ester, a chemical compound derived from oil) is a man-made fibre that simply didn’t exist until scientists invented it in 1941. When it launched publicly in 1951, it was marketed as a “wonder fabric” — and honestly, it was.
Why Polyester Was Revolutionary
Compared to traditional fibres like wool and cotton, polyester felt revolutionary. No more scratchy jumpers, no more endless ironing. Instead, we got a fabric that was:
Lightweight
Wrinkle-free
Easy to wash and wear
Hard-wearing and durable
Within just a decade, polyester had taken over the clothing industry. Today, an estimated 50–60% of all clothing is made with polyester — whether as a pure fabric or a blend. That means nearly half the people on earth are wearing polyester at any given moment.
How Polyester Is Made
The Science Behind Polyester
Polyester is derived from petroleum. Its key building blocks — ethylene glycol and terephthalic acid — are extracted from crude oil and combined to form polyethylene terephthalate (PET). (Yes, the very same PET used to make plastic bottles!)
From there, the process looks like this:
PET is hardened and cut into tiny pellets.
The pellets are melted and spun into threads.
The threads are woven or knitted into fabric.
The fabric is dyed, coated, treated, or finished.
Conventional value chain for polyester garments- Analysis of the polyester clothing value chain to identify key intervention points for sustainability
This process is what makes polyester so versatile. It can become shiny “silk,” heavy-duty waterproof jackets, soft fleece, or super-stretchy leggings — all depending on how it’s processed.
Why Humans Invent Things We Don’t Always Need
Around this point in my research, I couldn’t stop thinking about a line from a book I read recently, The Mountain in the Sea by Ray Nayler (not sewing-related at all — think homicidal octopuses!). There’s a quote in it that has been rattling around in my brain ever since:
“The great and terrible thing about humankind is simply this: we will always do what we are capable of”
And I think that applies perfectly to polyester. We already had fabric — cotton, wool, silk — but we wondered if it could be better. We were capable of making a new alternative, so we did. Why? Because we could.
Is Polyester Safe to Wear?
The Chemicals Used in Fabric Production
Polyester itself isn’t inherently toxic to skin. The bigger concern is the chemicals used during production — and this is true for many fabrics, even natural fibres. These chemicals can be extremely toxic and irritate skin, so if you don’t pre-wash your fabric before sewing (I have been guilty of this before!), I highly recommend you start. The residue left on fabric and clothing can be quite nasty.
Microfibres and Health Concerns
Many synthetic fabrics, including polyester, are known to pill or shed fibres — think of brushed fleece, squishy knits, or faux fur. These tiny fibres can become airborne or wash out in the laundry, and we now know they can end up in our lungs. Microfibres have been found in human tissue, and early research suggests they may worsen asthma and respiratory conditions, and even trigger serious inflammatory reactions.
Polyester’s Environmental Impact
Microplastics and Our Oceans
This is where polyester’s biggest issue lies — its environmental footprint.
Every single wash of polyester clothing can release up to 700,000 microfibres into waterways. By 2050, scientists estimate that 2.2 million tonnes of microplastics will be polluting our oceans.
These fibres carry toxins, get eaten by marine life, and eventually end up back on our plates. That lovely piece of fish you enjoy for dinner? It might contain more plastic than you’d get from the jacket you just made.
Alternatives to Polyester
Linen
Historically, linen was the undergarment fabric of choice — keeping people cool and preventing odour. Linen shifts were worn next to the skin, almost like underwear.
It has brilliant wicking properties, is antibacterial, and thermoregulating — but it wrinkles like crazy, which is one reason I rarely wear it.
You can buy loose linen shorts or yoga pants marketed as “activewear,” but they don’t look or feel like the tights and fitted tops I usually wear to the gym. Still, linen could work for light activities like walking or yoga.
Merino Wool
Merino wool is ultra-fine and soft enough to wear against the skin — I have several merino cardigans and thermals and they’re some of my comfiest pieces.
It’s breathable, odour-resistant, moisture-wicking, and even comfortable when wet. Brands are now making merino leggings, base layers, and thermals — though 100% merino activewear is harder to find, especially for fitted pieces like sports bras or leggings.
Cotton
Cotton t-shirts are already part of my workout wardrobe — but I don’t sweat a lot, so I don’t mind their slower drying time.
For heavy sweaters, cotton can become heavy, stay wet, and rub uncomfortably. It also lacks stretch recovery, so it won’t work for those who like tight-fitting leggings unless blended with spandex (plastic).
Bamboo / Rayon
Rayon (including bamboo) is made by chemically processing cellulose — and that process can be incredibly toxic to both workers and the environment. So, “natural” doesn’t always mean “less harmful.” The one upside is that rayon will biodegrade over time — something polyester won’t do.
It’s breathable, moisture-wicking, and UV-resistant, which makes it great for running in hot climates — but knowing the environmental cost makes me far more hesitant to use it.
Lyocell / Tencel
Lyocell (Tencel) is made from wood pulp using a much cleaner, closed-loop manufacturing process. Essentially, the industry recognised how harmful the rayon/bamboo process was and dramatically improved it.
It’s more absorbent than cotton and wicks moisture well, though it isn’t quite as antibacterial as wool or polyester. Still, it’s becoming increasingly common in activewear — a good sign that brands are embracing better production practices.
Innovative Bio-Based Synthetics
New fibres like Sorona are designed to use fewer fossil fuels while still delivering the performance benefits of polyester. This feels like a promising area for the future — and many major brands are now investing heavily in research and development to expand these more sustainable options.
My Takeaway
After all this, I’d love to say I’m never going to use polyester again — but that wouldn’t be true, and I don’t want to lie to you. There’s a reason polyester makes up 60% of all clothing: for some garments, it’s simply the best option if you want durability, stretch, and easy care.
That said, I can make better choices. I’ll avoid polyester for fashion sewing, stick to cotton T-shirts for workouts, and experiment with merino for leggings and underwear.
And before I attempt to make my own, I think I’ll try buying a pair of merino workout leggings first — Merino Country has a pair I’ve been eyeing, and I’m genuinely curious to see how they perform.
I learned so much while researching this post, but I know there’s still a lot more to discover. I’d love to know if you’ve found other great alternatives to polyester. Have you ever made your own activewear? Do you also worry about the effects of polyester and want to limit its use in your me-made wardrobe?
Maybe one day I really will have a fully natural closet. The more I learn, the more I feel inspired to try — and to do better.
Happy Sewing!
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