What Is Polyester Actually Made Of? The Truth About Your Athletic Wear

Published in: The Drøn Journal · Category: Natural Fibres · 3 min read

 

Most men never think about what their athletic wear is actually made from.

You pull on a tee before the gym. You feel the stretch. You see the brand name. You pay the price. But the question of what's actually sitting against your skin while you train — sweating, pushing, breathing hard — rarely gets asked.

It should. Because for most athletic wear, including tees sold by brands charging $60, $90, and $120, the answer is polyester.

And polyester is plastic.

Polyester Is a Petroleum Product

Polyester — polyethylene terephthalate, if you want the full name — is a synthetic polymer derived from petroleum. The same family of materials used to make plastic bottles. It was developed in the 1940s as a cheap industrial alternative to natural fibres like cotton and wool.

It found its way into athletic wear because it stretches, dries fast, and costs very little to produce. From a manufacturing standpoint it's an efficient material. From a human standpoint — the person wearing it, against their skin, during physical exertion — the story is more complicated.

What Polyester Does to Your Body

Polyester does not breathe the way natural fibres do. The fibre structure is dense and does not allow air to circulate freely, which means heat and moisture generated by your body during exercise have nowhere to go. You feel this as that sealed, airless feeling during a hard session — the sense that your body's heat is being held against you rather than released.

Beyond the thermal experience, polyester creates an environment that natural fibres don't. The warm, damp, low-oxygen space between a synthetic fabric and sweating skin is ideal for the anaerobic bacteria responsible for body odour. Those bacteria embed themselves in polyester's fibre structure at a microscopic level. Washing helps but doesn't fully remove them — which is why a synthetic athletic tee can start smelling early in its life regardless of how frequently you wash it.

Some wearers also experience skin reactions from extended contact with synthetic fabric during exercise — friction irritation, heat rash, and prolonged skin sensitivity after long sessions. This is more common than the athletic wear industry acknowledges and more common than most men realize, partly because they've never worn anything different.

What Polyester Does After You're Done With It

The conversation about what polyester does to your body during wear is one thing. What it does after your wardrobe is done with it is another.

Polyester does not biodegrade. A synthetic tee discarded after a year of use will sit in landfill for approximately 200 years. During its useful life — and during every wash cycle — it sheds microplastic particles. These particles are too small to be captured by most water treatment systems. They enter rivers, lakes, and oceans.

They have been found in the tissue of fish, seabirds, and marine mammals. They have been found in human blood.

This is not a marginal concern. Polyester accounts for roughly 52% of global fibre production. The cumulative volume of microplastics entering water systems from synthetic clothing is one of the least discussed and most significant sources of plastic pollution on the planet.

Why Natural Fibres Are Different

Natural fibres — bamboo, cotton, wool, linen — come from plants and animals. They have been used in clothing for thousands of years because they work with the body rather than against it. They breathe. They regulate temperature. They biodegrade at the end of their life.

Bamboo specifically has properties that make it particularly well suited to performance and athletic contexts — natural antimicrobial properties that prevent odour-causing bacteria from establishing, a fibre structure that allows air circulation even during intense activity, and exceptional softness that doesn't create friction irritation against skin.

Cotton adds structure and durability. Together — as in the Intent Tee's 65% bamboo, 28% cotton blend — they deliver what synthetic fabrics promise but don't deliver: genuine performance without the plastic.

For the full breakdown of how bamboo, cotton, and polyester compare across every performance metric — read our complete fibre comparison in The Science Behind Drøn's Fabric.

The athletic wear industry has convinced an entire generation of men that plastic fabric is performance fabric. It isn't. It's the cheapest material available at the highest markup the market will tolerate.

Natural fibres existed before polyester. They'll outperform it long after the synthetic trend runs its course.