The work-out leggings material you've got to avoid.

Ahh, activewear. The best trend to ever be bestowed on us. Because it is now okay for us to wear leggings just about anywhere (don’t fight me on this). 

But there can be one little, itty-bitty, stinking problem. In the vag area. Which is a bummer when athleisure is basically our uniform.

A textiles expert told Refinery29 that the material your leggings are made of can influence the odour down there — especially if you exercise in them (yes, some people use them for their actual purpose).

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Basically, opting for the synthetic, stretchy stuff is just asking for a pungent parfum.

“Polyester, which is required to make clothing stretchy, is non-polar and non-absorbent. This is what makes it so famously ‘sweat-wicking’,”  said Rachel McQueen, a University of Alberta professor.

“On top of that, because it repels water, polyester is harder to clean in the washing machine, which might be why, even after you wash your workout clothes, the odour sometimes just doesn’t go away.”

She continued, explaining that smells clung to polyester’s surface and wafted away slowly over time, leading to a continuous all-day stench. Lovely.

The best material might actually be, weirdly, wool. Not the fluffy stuff, but fine merino, performance wool.

Image via iStock.

McQueen said wool was better for odour control because it was much more absorbant, a well as sweat-wicking to release moisture and smells easily and fast.

But look, for us regular, simpler souls out there, cotton is a safe choice.

It absorbs sweat and smells, trapping the chemical compounds that make up odours, leading to only a discreet scent.

And McQueen said when you washed cotton, the water got inside the fibres and cleansed away all the smelly chemical compounds.

Cotton only becomes an issue when it is in a continuously humid state. It tends to get a musty smell when it doesn't dry out quick enough.

So change out of your leggings soon after a sweaty work-out and wash and dry them when you next do laundry -- sooner rather than later -- to avoid stinking them up.