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Twitter user claims acids in vagina causes lighter patches on underwear – We fact-checked

Claim: Twitter post claims the vagina is acidic and has a pH between  3.8 to 4.5

It is true that the vagina has a PH level of between 3.8 and 4.5 which is strong and capable of changing the appearance of materials, but this cannot be categorically linked to the lighter patches on the underwear because it is not proven.

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A Twitter post by Vagina Museum (@vagina_museum) claims the vagina is acidic and this is what causes lighter patches on dark underwears. The post claims the pH of the vagina is between 3.8 to 4.5.

As of Monday, February 22, 2021, the post had generated 33,000 Retweets, 6,345 Quote Tweets and over 95,000 likes.

“Do you find lighter patches in your dark underwear? IT’S NORMAL! Your vagina is acidic and has a pH of 3.8-4.5. That’s acidic enough to bleach fabric, and that’s what’s happening.”

Screenshot of the Twitter Post.


Dubawa conducted a keyword search on the acidity of the vagina.

According to Healthline, a normal vaginal is moderately acidic with pH level between 3.8 and 4.5. 

What constitutes a “normal” pH level can, however, vary slightly based on your stage of life; during your reproductive years (ages 15 to 49), the vaginal pH should be below or equal to 4.5 but before menstruation and after menopause, a healthy pH tends to be higher than 4.5.

Another report by medical news today agrees that a normal vaginal pH is less than 4.5. It also notes that the lower the number, the more acidic the vaginal environment will be.

Chart by Medical News Today.

Factors like unprotected sex, antibiotics, douching (washing the vagina), and menstrual periods can affect the pH level of the vagina. A high vaginal pH level (above 4.5) provides the perfect environment for unhealthy bacteria to grow. An acidic vagina usually doesn’t cause disease but if the acidity rises too much, it might reduce fertility.

Dubawa reached out to people to share their experience but this was difficult as most people were uncomfortable speaking about the topic. However, a young lady (age 23) who shared her experience but pleaded anonymity said she experienced these patches when was a little girl but not anymore. She noted the vagina is self-cleaning and its fluid is capable of causing this.  But she explained that she does not experience this as an adult  because she does not wear her underwear for long anymore and she uses pant liners.

Experts view

Speaking to a Gynaecologist, Dr Jerry Agim, he confirmed the vagina PH to be correct and that the level varies based on the different stages of life. For women, he explained that Oestrogen is a factor. It is responsible for the production of glycogen by the vaginal epithelial cell which is acted upon by the bacteria called lactobacilli to produce lactic acid which maintains the Vaginal PH at 4 to 4.5

“Yes, the vagina PH is about this range 4 to 4.5 for normal PH. For premenopausal women due to the high level of oestrogen, the PH is in this range, but for premenarchal and postmenopausal women the PH is slightly higher than greater or equal to 4.7 because less oestrogen is produced here. For a fluid with such PH, it’s not out of place for its acidity to cause this but this is not proven. The effect on the underwear depends on the nature of the material; more with cotton, and also on the duration of use.”

A midwife, Grace Odoma, who also spoke to Dubawa said “the vagina fluid has high acidity and is capable of causing any stain on any material. Yes, the type of material also matters and how long the underwear is used. This lighter patch is not a problem but a good sign the person is healthy and has a normal floral or good activity in the vagina. So those light patches you are seeing is a result of the high acidity of the vaginal fluid. While some will not notice this is because they change their pants regularly or the type of material in use does not show the effect of the fluid or because they use pant liners.

Another health expert attributed lighter patches to the acidic nature of the vagina and washing.

“The acidic nature and repeated washings can cause this. It also happens in men’s undies because of repeated washing too.”


While it is true that the vagina has a PH level of between 3.8 and 4.5 which is strong and capable of changing the appearance of materials, this cannot be categorically linked to the lighter patches on the underwear because it is not proven and there are other factors that may influence the patches like the type of material, the period of use and washing.

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