Is Polyester Bad for You? What to Know (and What to Wear Instead)

So… is polyester bad for you?

It's not completely "evil" like it has been portrayed recently. But it’s also not what your body and skin naturally love.

Polyester is a synthetic fibre made from petroleum (...oil). It’s widely used in activewear because it’s durable, stretchy, and holds its shape well, especially for high-intensity workouts.

But when it comes to how it performs and feels on your skin, it’s a different story.

Polyester doesn’t breathe the same way natural fibres do. It tends to trap heat and sweat against your body, which can create a warm, slightly damp environment,  basically the perfect place for bacteria to grow. That’s often why synthetic activewear can start to smell quickly (and at times still smells even after washing).

Because the fibre is hydrophobic (it repels water), sweat doesn’t get absorbed and released in the same way. It sits between your skin and the fabric. Not ideal if you’re wearing it for hours beyond your workout.

There’s also increasing conversation around chemical treatments used in some synthetic textiles, like PFAS (sometimes called “forever chemicals”), which can be added for things like water or stain resistance. 

And then there’s the environmental side: polyester sheds alot microplastics in the wash and during wear and doesn’t break down over time.

So why do people still wear it?

Because it works depending on your movement/workout:
For intense training, long runs, or high-performance sports, synthetic fabrics can make sense.

But for everyday movement?
That’s where we think there’s a better option.

What we prefer instead

At bai active, we lean into natural based fibres like bamboo, organic cotton, Tencel Modal. They’re softer, more breathable, no added chemical coatings and feel calmer on your skin. So you'll want to stay in them all day instead of getting that icky smelly feeling.

Because movement doesn’t just happen in the gym. It happens everywhere.