Let's get straight to it — here's what actually matters on this one.

• Fabric softener coats fibers with a waxy layer that can reduce moisture-wicking and breathability over repeated use, especially on technical or cotton fabrics.
• This coating buildup is a common, overlooked cause of workout and moisture-wicking fabrics losing their performance over time.
• Softener residue can also trap odor rather than washing it out, ironically making clothes smell worse over repeated use.
• Using softener sparingly, or switching to wool dryer balls for softness, avoids this buildup while still reducing static and stiffness.

The fit-and-fabric-health takeaway: The very product marketed to make fabric more comfortable can quietly reduce the breathability that comfort actually depends on.

Next up: check out our guide on the next post in your fit and fabric health series.