When most people think about reducing plastic, they think about water bottles, food containers, or grocery bags. But there’s one source of plastic exposure that often goes unnoticed: the clothes we wear every day.
In fact, many underwear brands are made primarily from synthetic materials such as polyester, nylon, and acrylic, all of which are forms of plastic. These fabrics have become common because they are inexpensive, stretchy, and easy to manufacture. Yet they are also some of the materials that sit closest to our skin for the longest periods of time.
As Plastic Free July encourages people to rethink their everyday choices, it may be worth asking a question that rarely gets discussed:
Is your underwear made of plastic?
In this article, we'll explore why synthetic fibers are so common in underwear, what they mean for the environment and everyday wear, and how to choose healthier, lower-plastic alternatives without sacrificing comfort.
The Surprising Amount of Plastic in Modern Clothing
Many consumers are surprised to learn that a large portion of today's clothing is made from plastic-based fibers.
Polyester, nylon, acrylic, and elastane (also known as spandex or Lycra) are all synthetic materials derived from fossil fuels. According to the Textile Exchange Materials Market Report 2024, polyester accounted for approximately 57% of global fiber production in 2023, making it the most widely used textile fiber in the world
These materials are popular because they offer durability, stretch, moisture management, and low manufacturing costs. However, their widespread use means that plastic has become deeply embedded in the clothing industry.
This includes underwear, bras, activewear, swimwear, and many everyday basics.
Why Does Plastic End Up in Underwear?
There are practical reasons why synthetic materials became the industry standard.
Plastic-based fibers are inexpensive to produce and can be engineered to provide stretch, shape retention, and moisture-wicking performance. For brands focused on maximising margins, synthetic fabrics often offer a cost-effective solution.
The challenge is that many consumers don't realise these materials are plastic in another form.
An underwear label that lists polyester, nylon, or acrylic may not immediately register as plastic, even though those fibers originate from petrochemicals.
Some brands use blends that combine natural and synthetic fibres, while others rely almost entirely on plastic-based fabrics.
What Happens When Plastic Sits Against Your Skin?
Your skin is your body's largest organ, and it remains in constant contact with your clothing throughout the day.
While research continues to explore how different materials interact with the body, many consumers are increasingly choosing natural fibers because they prefer materials that are breathable, plant-based, and less reliant on synthetic chemical processing.
There are also practical comfort considerations. Natural fibers such as cotton and hemp tend to be breathable and moisture-absorbing, which may help create a more comfortable environment compared to certain synthetic fabrics.
For garments worn closest to the body, such as underwear, fabric choice can play an important role in overall comfort.
The Environmental Impact of Plastic Clothing
The conversation around plastic clothing extends beyond what we wear.
Every time synthetic garments are washed, they can release tiny plastic particles known as microplastics. These microscopic fibres can pass through wastewater systems and eventually enter rivers, lakes, and oceans.
Research published by organisations including the International Union for Conservation of Nature (IUCN) has identified synthetic textiles as a significant source of primary microplastic pollution in marine environments.
Unlike natural fibres, plastic fibres do not readily biodegrade. They can persist in ecosystems for decades.
This means that the polyester underwear purchased today may continue to exist long after it has been discarded.
How to Tell If Your Underwear Contains Plastic
One of the easiest ways to determine whether your underwear contains plastic is to check the fabric label.
Common plastic-based fibres include:
- Polyester
- Nylon
- Acrylic
- Polyamide
- Elastane
- Spandex
- Lycra
Many brands market their products as soft, breathable, or sustainable without clearly highlighting the fibre composition.
Taking a moment to read the label can reveal what the garment is actually made from.
What Are the Alternatives?
For those participating in Plastic Free July, eliminating every synthetic fibre isn't always realistic. Many garments require a small amount of stretch for comfort and durability.
Instead, a more practical goal is reducing the overall percentage of plastic in the clothing worn closest to the skin.
Natural fiber options include:
Organic Cotton
Organic cotton is grown without synthetic pesticides and is often processed under stricter standards than conventional cotton. Certified organic cotton can also help improve transparency throughout the supply chain.
If you'd like to learn more, read our guide:
Organic Cotton vs Conventional Cotton
Hemp
Hemp is one of the oldest textile fibers in the world and requires significantly fewer agricultural inputs than many conventional crops. It is naturally breathable, durable, and plant-based.
Lower-Plastic Blends
Some brands combine natural fibers with a small amount of elastane or spandex to provide stretch while maintaining a predominantly plant-based fabric composition.
Rather than focusing on perfection, many consumers are choosing fabrics that significantly reduce their reliance on plastic.
Plastic Free July Starts With Everyday Choices
Plastic Free July isn't about being perfect.
It's about becoming more aware of the products we use every day and making intentional changes where possible.
Many people start with reusable water bottles or grocery bags. Others switch cleaning products or reduce plastic packaging.
But clothing is often overlooked, even though it's one of the things we interact with most.
The fabrics we wear become part of our daily environment. They sit against our skin, travel with us throughout the day, and accompany us through some of life's most personal moments.
That makes them worth paying attention to.
A Quick Check-In
Take a look at the underwear you're wearing right now.
What materials are listed on the label?
If the answer includes polyester, nylon, or acrylic, your underwear contains plastic.
There's no judgment, most people have no idea.
But awareness is where change begins.
Final Thoughts
Plastic has become so common in modern clothing that many people don't realise they're wearing it every day.
As Plastic Free July encourages us to rethink our habits, clothing deserves a place in the conversation. Understanding what your underwear is made from is a simple but powerful step toward becoming a more informed consumer.
You don't need to overhaul your entire wardrobe overnight. But the next time you're replacing your everyday essentials, take a moment to check the label.
Because what touches your skin every day matters.
And small choices, repeated over time, can make a meaningful difference.
Frequently Asked Questions
Is polyester considered plastic?
Yes. Polyester is a synthetic fiber made from petroleum-based materials and is considered a form of plastic.
Is all underwear made from plastic?
No. Some underwear is made primarily from natural fibers such as cotton or hemp, although many styles include some synthetic fibers for stretch.
What fabrics should I avoid if I want less plastic in my clothing?
Look for polyester, nylon, acrylic, polyamide, and other synthetic fibers commonly derived from fossil fuels.
Is organic cotton plastic-free?
Organic cotton itself is a natural plant fiber and is not plastic. However, some garments made from organic cotton may still contain a small percentage of elastane or spandex for stretch.
Why does Plastic Free July matter?
Plastic Free July encourages people to reduce unnecessary plastic use and become more aware of everyday products that may contribute to plastic pollution, including clothing.