You may look great in your new workout gear but after a few visits to the gym you may not smell so great. It’s not necessarily you; it’s the fibres in some of those stretchy moisture wicking fabrics that hold the stink.

“Sweat evaporates, but what’s left behind are odor-causing chemicals on the surface of the synthetic fibers. They can be difficult to wash out, and they can build up over time,” said Haniya Rae, Consumer Reports Home Editor.

The challenge is that some of the newer gym workout clothes are made from more delicate fibres and they may need special care to protect that shape and fit. So what can you do to keep your leggings and t-shirts in tip-top shape? First try washing them as soon as you finish your workout.

“Keeping these synthetics bunched up and damp promotes bacterial growth, which gives off odors, making them smell even worse! Pre-treat any stains and turn them inside out! This allows the water and detergent to focus on the soils that have accumulated on the inside of your clothes,” said Rae.

Cold water washing prevents fading and preserves the fit of synthetics fibres. Choose the gentle cycle and if your washer has an extra rinse cycle, use it.

Consumer Reports tests of laundry detergents found that Tide Plus Ultra Stain Release is excellent at removing body oil. However, follow the directions carefully and don’t overdo it. Too much detergent can leave residue that traps odors.

It’s also recommended to avoid the dryer. Most experts recommend air drying synthetic workout gear and even laying them flat to protect the shape and fit.