If youâve ever pulled a pair of underwear out of the laundry only to notice strange light patches or discoloration in the fabric, youâre not alone. Many women have experienced this odd phenomenon, but few realize whatâs actually causing it.
While itâs easy to assume your washing machine or detergent is to blame, the real culprit is something completely naturalâyour own body.
According to a female obstetrician-gynecologist who goes by âThe Vag Docâ on TikTok, this so-called âbleachingâ effect is caused by the acidity of vaginal discharge.

A Doctor Wearing Eyeglasses Using a Tablet, Photo Credit:Â Pexels
The Science Behind the âBleachingâ Effect
In a now-viral video, The Vag Doc explained that the vagina maintains a delicate balance of bacteria, primarily lactobacilli, which help keep the area healthy. This bacteria creates an acidic environment that prevents infections and maintains overall vaginal health.
âWhen your vagina is working as it should, it has a specific pH balance that includes lactobacilli and other bacteria,â she explained. âThis acidity is essentially what helps keep your vaginal microbiome in check.â

Feminine underwear drying on rope with clothespins, Photo Credit:Â Pexels
But hereâs where it gets interesting: that same acidity is also responsible for lightening or âbleachingâ the fabric of your underwear over time.
âIf your discharge is more acidic, it can actually strip the dye from your underwear, leaving behind lighter patches,â she said.
Is It a Sign of a Problem?
The good news? This bleaching effect is completely normal and doesnât mean anything is wrong. In fact, itâs often a sign that your vaginal pH is exactly where it should be.

A female OBGYN known online as The Vag Doc, Photo Credit:Â the.vag.doc/Instagram
âA normal, healthy vagina can sometimes cause discoloration in underwear, so thereâs no need to panic,â she assured viewers. âItâs just science at work.â
What If Your Underwear Doesnât Change Color?
Some women in the comments had concerns that their underwear had never shown signs of bleaching. Was that a problem?
âNot necessarily,â The Vag Doc explained. âSome people just have less acidic discharge than others, and thatâs as well normal.â
Another viewer asked whether different fabrics or dyes could affect how much bleaching occurs. The answer? Absolutely. âThe type of fabric, its color, and the dye used in the material can all influence whether or not you notice bleaching,â she confirmed.

A female OBGYN known online as The Vag Doc, Photo Credit:Â thevagdoc/Tiktok
When to Be Concerned
While some vaginal discharge is completely natural, certain changes can signal a problem. The Cleveland Clinic advises women to seek medical attention if they notice unusual changes in their dischargeâsuch as a strong odor, a different color, or a change in textureâas these could indicate an infection or other health issue.
But as for that unexpected bleaching in your underwear? Thatâs just your body doing what it was designed to do.