Built-In Antibacterial Yarn for Sports Bras: Buyer Guide
Buyers sourcing medium support sports bras with real odour control usually ask the same five questions. Here is how we answer them for Built-In Antibacterial Yarn.
How does it actually work
Built-In Antibacterial Yarn relies on antibacterial masterbatch added before spinning. In practice the active agent is locked inside the fibre so it cannot wash off the surface. If a supplier cannot explain the mechanism in one sentence, they are probably selling a fragrance that washes out in three cycles. The sweat zone for medium support sports bras is the underband and the centre front panel, which is where the treatment has to sit.
What target should I write
Write above 99% bacterial reduction retained after 50 washes measured by JIS L 1902 antibacterial test. Naming the standard matters more than the headline number, because antibacterial results are not comparable across different test methods. Every lot is measured against JIS L 1902 antibacterial test before the fabric is released for cutting.
How long will it last
Expect 50 washes or more under normal care. Ask for results after washing rather than only as delivered, and make the care label say standard home laundering with no special requirement. Cost impact is a yarn premium of 6-10%, which is usually recovered through fewer returns across a season.
What does it cost
Budget a yarn premium of 6-10%. Against the cost of a returned garment and a lost repeat customer, that is a modest amount, and it is easier to defend than a price rise later. Wear trials were run under gym work, running and studio practice rather than in the laboratory alone.
How do I check a shipment
Take fabric from the bulk lot, not the sample book, and repeat JIS L 1902 antibacterial test. Keep the report with the shipment documents so any claim can be answered with data instead of opinion. The care label states standard home laundering with no special requirement, and that wording is the condition behind 50 washes or more.
