Many people have long wondered about the cause of those unusual light or faded patches that sometimes appear on underwear. The good news is: there’s finally a clear explanation — and no, your washing machine isn’t to blame.
You may have heard comments or jokes about the strength of certain body areas, but the truth is actually rooted in science. It might surprise you to learn that the natural pH levels of the vagina can sometimes cause a lightening or “bleaching” effect on fabric.
Have you ever noticed faded patches on your underwear?
Plenty of individuals have experienced this and even worried that something might be wrong — whether with their laundry detergent, fabric quality, or washing machine. But the real reason is both simple and perfectly normal. These faded spots are actually caused by the vagina’s natural acidity.
This acidity is measured by pH levels — which help determine how acidic or alkaline something is. A healthy vaginal pH typically ranges between 3.8 and 4.5. That level of acidity can, over time, interact with the dye in underwear fabric, leading to lightened areas.
Many people have shared their experiences online, pointing out that this is nothing to be concerned about. In fact, it’s a sign of good health. One user explained it well in a tweet: “It’s completely normal to find lighter spots on women’s underwear due to the vagina’s natural pH. That’s not bad hygiene — it’s actually a sign that everything is functioning healthily.”
So, if you’ve seen this before, there’s no need to worry. It’s a natural part of how the body maintains balance and health — and it’s much more common than you might think.