Hong Kong's hot, humid summers mean bus and MTR rides often bring waves of body odor, with quick-dry athletic wear being a major culprit for lingering, unpleasant smells! Netizens on social media ask: why do quick-dry clothes develop a persistent odor after being worn, even after multiple washes? What exactly is the problem? And is there a way to completely solve it? An expert shares a set of deodorizing methods specifically for quick-dry underwear and sportswear to help people solve their clothing odor problems.
A netizen posted on Threads urging people with body odor to wear cotton shirts instead of quick-dry athletic wear, otherwise "the smell will be so strong the whole street can smell it." The post sparked widespread discussion, revealing that many in Hong Kong have had similar experiences: after sweating in quick-dry athletic wear, the clothes dry quickly, but the sweat odor stubbornly clings, failing to wash out even with laundry detergent.
One netizen noted, "The high-density fabric traps sweat residue, allowing bacteria to grow." Another helplessly commented, "No matter how much you wash, it doesn't work. If the clothes stink, you should just throw them away." In fact, the reason quick-dry clothes get smellier with washing isn't due to personal body odor, but to the specific structure of the fabric.
Japanese laundry expert Hana explains that functional quick-dry underwear and sportswear, despite being thin and light, are actually made of multiple fiber layers:
However, this multi-layer fiber structure, combined with polyester's tendency to absorb sebum (skin oils), causes sweat oils and proteins to get trapped deep within the fibers. Regular laundry detergents struggle to penetrate fully, and over time, this creates a stubborn, increasingly smelly odor.
Hana points out that leaving clothes soiled with sebum and sweat allows odor-causing bacteria to multiply rapidly. These bacteria can form a tough "biofilm" deep within the fibers – like "dental plaque hardening into tartar" – after which laundry detergent cannot penetrate, making the odor difficult to remove even with bleach. Therefore, wash clothes as soon as possible after taking them off; do not let them sit overnight.
For lingering odors already trapped in quick-dry clothes, Hana proposes three methods:
1. Use Weak Alkaline Powder Detergent
Sweat and sebum are acidic. Using a weak alkaline detergent (opposite pH) neutralizes and removes dirt more effectively. Neutral liquid detergents are generally weaker. Powdered weak alkaline detergents are recommended. However, powdered detergents often contain optical brighteners, which are not suitable for colored clothes. Look for eco-friendly, fluorescent brightener-free powdered detergent when purchasing.
2. Soak with Oxygen Bleach for Sterilization
If odors are noticeable, detergent alone is insufficient; soaking with bleach is also needed. Use oxygen bleach (powder form). Do not use chlorine bleach (destroys clothing color) or liquid bleach (weaker cleaning power).
Method:
Effectiveness: Hot water generates oxygen bubbles that help loosen and lift sebum and dirt, effectively removing odors.
3. Cationic (Inverse) Soap for Stubborn Biofilm
If odors persist after the above steps, a biofilm has formed. This requires medical-grade "cationic soap," often used by medical staff as a disinfectant before surgery. It has no cleaning power itself, but its sterilizing ability is stronger than regular "antibacterial" products.
Method:
Odor Troubles Others
People often don't notice their own odor, but it can be troublesome for those around them. While the dryness and comfort of quick-dry clothes are important, proper cleaning and maintenance are essential to wear them with confidence, keeping every piece of athletic wear fresh and odor-free.
Sources: Laundry Expert Hana, sugar_sweet_evildoer @ Threads
