Understanding Laundry Marks on Clothing! Causes and Simple Tips..
The lightened or bleached area that sometimes appears in cotton underwear is completely normal and is caused by the vaginal microbiome. Beneficial bacteria (mainly Lactobacillus) produce lactic acid, which keeps the vaginal environment acidic (pH 3.5–4.5) to protect against infections. When this natural discharge comes into contact with fabric—especially absorbent cotton—the mild acid can gradually fade the dye, similar to a gentle bleaching effect. The intensity varies depending on individual pH, hormones, fabric type, and washing habits. Rather than being a problem, this is actually a sign of a healthy, well-functioning body, though unusual changes in smell, texture, or discomfort should be checked by a doctor.
