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4 Signs Your Vaginal pH Is Out of Whack

If you haven't thought about pH since high school chem class, don’t worry—we’ve got you covered with this field guide to the essential vaginal health metric.

7 minutes

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From your bloodstream to your digestive system, each part of your body has a unique “potential of hydrogen” (which you probably know as pH) level. And the vagina is no exception. But what regulates your vaginal pH, and what happens when it gets disrupted? Here’s our lowdown on vaginal pH, why it’s crucial for your health, and how to spot when yours is out of whack. 

What Is the Ideal Vaginal pH?

You might remember from chemistry class that the pH scale measures the hydrogen ion activity in a water-based solution. The scale ranges from 0 to 14, with seven being neutral. Anything below seven has a high concentration of free hydrogen ions and is considered acidic, while anything above seven is alkaline or basic. To put it in perspective, battery acid has a pH of around one, while lemon juice hovers around three. 

Different organs in the body require different pH levels to function optimally. For example, the stomach has a highly acidic pH of around 1.5-2.0, ideal for breaking down food.1 In the brain, where there is less need for free hydrogen, pH levels tend to be more alkaline and fall around 7.2-7.4.2 Vaginal pH is moderately acidic and lands somewhere in the middle. Ideally, the pH value for a woman of reproductive age is between 3.8 and 5.0, though it may temporarily increase during menstruation or menopause (due to fluctuations in estrogen).3,4 

Wondering why your number matters? “Vaginal pH is a crucial aspect of vaginal health, serving as a key indicator of the microbial balance within the vagina,” explains Ava Mainieri, Ph.D., a geneticist and evolutionary biologist specializing in female reproductive health.

Vaginal pH is largely dictated by the vaginal microbiome—a complex community of microorganisms that inhabit the female reproductive system. Ideally, the vaginal microbiome is dominated by Lactobacillus, a genus of bacteria that produce lactic acid. This lactic acid reduces the pH of the vaginal environment, making it unsuitable for pathogenic microbes (read: bad guys) to settle in and multiply.3 Therefore, “[Lactobacillus species] support a balanced microbial ecosystem that protects against infections and maintains the integrity of the vaginal mucosa,” Dr. Maineri says.

If your vaginal microbiome is low in Lactobacillus species (which, unfortunately, is a pretty common occurrence), it will be less acidic and therefore more hospitable to invaders that cause yeast infections, bacterial vaginosis (BV), aerobic vaginitis (AV), UTIs, and more. In pregnant women, an increase in vaginal pH may lead to BV and spontaneous preterm deliveries, too.3

Once pathogens take root in the vagina, they can crowd out healthy lactobacilli—further fueling a dysregulated pH and opening the door to recurring vaginal issues.

What Can Affect Your Vaginal pH?

Several factors influence the microbial makeup and pH level of your vagina, including menstrual blood, hormones, and external irritants like tampons, lubricants, or semen. Although the vaginal microbiome is designed to self-balance pH, certain factors can disrupt this delicate equilibrium. These include: 

  • Your period: Menstrual blood is slightly alkaline, which can temporarily elevate the vaginal pH.5
  • Menopause: Postmenopausal people may experience a slightly higher vaginal pH due to a decrease in estrogen.3 
  • Unprotected sex: Semen has an alkaline pH (around 8) and might alter the vaginal pH during intercourse. Unprotected sex may also introduce pathogens into the vaginal microbiome, which can affect your natural balance and increase risk of infection.3
  • Antibiotics: Antibiotic medications kill harmful bacteria, but they also deplete the beneficial bacteria needed to maintain vaginal acidity.3
  • Douching: Cleansing the vagina can strip away good bacteria, leading to abnormal pH and heightened infection risk.6 Remember, despite what feminine hygiene ads want you to believe: your vagina is self-cleaning!

As mentioned earlier, an abnormal vaginal pH can pave the way for bacterial overgrowth, resulting in bacterial vaginosis (BV) or other vaginal infections. So, it’s always a good idea to be mindful of these factors and take steps to maintain proper pH in your vagina (more on that below).

Signs Your pH Is Off

There are a few telltale signs that your vaginal pH is not where it should be. “Look out for changes that are new to you, such as increased discharge, odor, or irritation, as these can be signs of a vaginal infection, indicating a possible pH imbalance,” advises Dr. Mainieri. Some red flags to look out for include:  

  1. Sudden itching or discomfort: If you’ve ever experienced itching down there after shaving or getting a wax, don’t worry—that’s normal. However, sometimes an imbalance in your vaginal pH can also cause unexplained itching, irritation, and redness around the vulva that makes it hard to go about your day.7 See your healthcare provider if you’re experiencing any unexplained itching or discomfort, as it can also be a symptom of a yeast infection or STI.8,9
  2. A burning sensation: Feeling a burning sensation during sex, when you pee, or when you insert tampons is another sign that your pH level might be off-kilter. This discomfort can stem from an imbalance of bacteria or yeast in your vaginal area caused by an infection. A burning sensation might be due to a yeast infection, and in other cases, it could be caused by an STI like chlamydia or gonorrhea.10 Remember, under normal circumstances, you shouldn’t feel any pain or discomfort during sex or when using tampons. If you are, it’s best to reach out to a healthcare provider for some advice. Your comfort matters, so don’t hesitate to seek help if something feels off.
  3. A strong, sudden odor: It’s completely normal and natural for your vagina to have an odor. It might smell yeasty, metallic, sweet, or even tangy, fermented, or sour due to the presence of lactobacilli. However, sudden or obvious changes to the way you smell can be an indication that something isn’t quite right. Infections like bacterial vaginosis (BV), trichomoniasis, or aerobic vaginosis (AV) can all cause a sudden, unpleasant vaginal odor.11,12,13 If you notice a fishy, foul, rotten, or stronger-than-usual smell out of the blue, it’s always a good idea to check in with your healthcare provider. 
  4. Unusual discharge: Vaginal discharge is nothing to be ashamed of. In fact, it’s something to celebrate, and a sign that your vagina is functioning as it should. Discharge, which helps keep the vaginal tract clean and well-lubricated, typically has a mild odor and can range from clear to white to pale yellow in color. However, sometimes pH imbalances can cause changes in the color, consistency, smell, and quantity of discharge.3 Depending on the specific cause, the discharge may become thick and white like cottage cheese, or thin and watery with a grayish or greenish hue. If you notice anything out of the ordinary with your discharge, flag it to your healthcare provider so they can rule out infections like BV or an STI.  

How to Maintain a Balanced pH

Maintaining a proper vaginal pH is key to preventing infections and ensuring overall vaginal health. Here are some steps you can take to keep yours in check:

  • Practice safe sex: Use barrier methods like condoms or dental dams during sex, and get regular STI check-ups. (The CDC recommends getting screened for STIs at least once a year.)14 
  • Avoid using douches and feminine hygiene soaps, and opt for unscented period products. 
  • Consider taking a vaginal probiotic, especially after antibiotic treatment. Look for one that is formulated with Lactobacillus strains that have been clinically studied for the vaginal microbiome. Suppositories are preferable to oral capsules, which seem to be less effective at reaching the vagina.15
  • See your healthcare provider if you experience symptoms of BV or other infections linked to high vaginal pH, such as a yeast infection. 

Vaginal pH: A Sliding-Scale Snapshot of Vaginal Health

Your vaginal pH gives you a peek into the conditions in your vagina at any point in time. A pH between 3.8 and 5.0 usually tells you that your vaginal environment is acidic enough to stave off potentially dangerous pathogens.

Understanding and managing vaginal pH is integral to promoting vaginal health and overall well-being. By tuning in to your body’s signals and looking after your vaginal microbiome, you can proactively reduce your risk of infections, complications, and uncomfortable side effects. Remember, your vaginal health matters—so prioritize it accordingly.


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