Why Does My Thinx Period Underwear Smell Like Ammonia?

An ammonia-like smell in period underwear (including Thinx) is a common issue many people notice. This usually happens because of a buildup of bacteria and sweat combined with urine residue — even if you didn’t actually urinate on them.

Possible Causes:

1. Residual urine or sweat:
   When urine or sweat isn’t fully washed out, bacteria break down the urea in urine and release ammonia, causing that sharp smell.

2. Not rinsing immediately:
   Letting the underwear sit too long with menstrual blood, sweat, or urine before rinsing can cause bacteria to multiply and odors to develop.

3. Washing issues:
   Using fabric softeners, bleach, or washing with hot water can damage the fabric’s absorbent layers or leave residues that trap odors. Also, not washing thoroughly enough can leave bacteria behind.

4. Body chemistry:
   Everyone’s sweat and body chemistry are different. Some people’s natural scent combined with bacteria can lead to stronger odors.

How to Get Rid of the Ammonia Smell:

• Rinse promptly: Rinse your Thinx underwear in cold water immediately after use to remove as much fluid as possible.

• Soak before washing: Soak in cold water with a bit of baking soda or an oxygen-based stain remover for 20-30 minutes.

• Use mild detergent: Wash with a gentle detergent that’s free of fabric softeners and bleach.

• Cold or warm wash: Use cold or warm water, avoid hot water which can set stains and odors.

• Air dry: Always air dry your period underwear—heat from dryers can break down fabrics and worsen odors.

• Repeat washing: Sometimes odors need a second wash to fully disappear.

Preventing Future Odors:

• Change and rinse your period underwear regularly, especially on heavy flow days.

• Avoid fabric softeners and scented detergents.

• Store clean underwear in a dry, well-ventilated place.

If the smell persists despite good care, it might be worth contacting Thinx customer support—they may have additional tips or can help with product issues.