Nylon Still Smells After Washing? Here’s Why—and How to Fix It

If your favorite leggings or sports bra still smells like sweat after washing, you're not alone. Nylon is a popular fabric in activewear because of its durability and stretch—but it’s also notorious for trapping odor. No matter how many times you wash it, that nylon stink just won’t quit.

The good news? You’re not stuck with it forever. With the right laundry routine, products, and timing, you can eliminate odor from nylon and keep your activewear smelling clean. In this guide, we’ll cover why nylon still smells after washing, how to fix it, and how to keep your gear fresher for longer.

Why Does Nylon Stink?

Nylon is a synthetic fabric commonly used in activewear, underwear, and compression gear. It’s lightweight, stretchy, moisture-wicking—and a total magnet for odor.

Here’s why:

• Nylon repels water but absorbs body oils and sweat

• These oils mix with bacteria, creating strong odor compounds

• Over time, those compounds get embedded in the fibers

• Regular detergents often fail to break them down completely

That’s why even after a wash cycle, nylon still smells, especially in high-sweat areas like underarms, waistbands, and inner thighs.

Common Mistakes That Make Nylon Odor Worse

If your nylon workout gear still smells after washing, your laundry habits might be contributing to the problem.

Avoid these common mistakes:

• Using detergent meant for cotton fabrics

• Adding fabric softener, which traps odor inside fibers

• Washing in hot water, which can “bake in” the stink

• Drying on high heat, which seals odor into the material

• Letting sweaty clothes sit too long before washing

These habits cause odor to build up over time, making it harder to get rid of.

Step 1: Wash Activewear the Right Way

Nylon needs different treatment than your regular laundry. If you’re tossing it in with your towels and jeans, you’re setting yourself up for lingering smells.

Here’s what to do instead:

• Turn nylon garments inside out

• Use cold water only

• Wash on a gentle or activewear cycle

• Avoid fabric softeners and bleach

• Wash separately from cottons or rough fabrics

For a detailed guide, check out our article:
👉 How to Wash Your Favorite Activewear Without Ruining the Fabric

Step 2: Use a Detergent That Actually Works on Nylon

Most conventional laundry detergents are built for cotton—and rely on fragrance to mask odor instead of actually removing it. That’s not enough for synthetic fabrics like nylon.

You need a liquid detergent made for synthetics that targets sweat, oil, and residue without harming stretch or softness. Look for a formula that:

• Works well in cold water

• Doesn’t include fabric softeners or waxy fillers

• Is made specifically for synthetic fibers and activewear

This is a crucial step in finally eliminating nylon stink.

Step 3: Soak for Deep Odor Removal

If your nylon still smells after washing, it’s time for a deeper clean. A cold water pre-soak can loosen up trapped sweat and bacteria before the main wash cycle.

Simple Pre-Soak Routine:

• Fill a sink or bucket with cold water

• Add 1–2 capfuls of your synthetic-safe detergent

• Submerge your nylon items and soak for 30–60 minutes

• Wash as usual (cold water, gentle cycle, no softener)

Do this every few weeks, or more often if your workout gear is especially smelly.

Step 4: Dry the Smart Way

Heat is not your friend when it comes to nylon. High temps can damage the fibers and lock in odor that wasn’t fully washed out.

Instead:

• Air dry flat or hang in a well-ventilated space

• If using a dryer, choose low or no heat

• Don’t mix nylon with heavy or damp items like towels

• Reshape garments while damp to maintain fit

Drying properly helps preserve your fabric’s stretch, breathability, and smell.

Step 5: Prevent the Smell from Coming Back

Once you’ve tackled the nylon stink, keep it gone with these simple steps:

• Wash gear ASAP after sweating—don’t let bacteria sit

• Turn gear inside out before tossing in the hamper

• Store worn gear in a breathable bag, not a sealed plastic one

• Wash after every wear—nylon collects odor fast

• Follow a consistent wash routine using activewear-safe detergent

Final Thoughts

If your nylon still smells after washing, it’s not your imagination—and it’s not your hygiene. Nylon is a high-performance fabric, but it needs a high-performance laundry routine to match.

Avoid heat, ditch the softeners, and treat your gear with the care it deserves. For an in-depth breakdown of washing techniques, read our full post:
👉 How to Wash Your Favorite Activewear Without Ruining the Fabric

With the right habits, you can finally ditch the nylon stink and make your activewear last longer—and smell better.