Is there such thing as normal vaginal pH?

TL/DR: The term “vaginal pH balance” refers to the relative acidity or alkalinity of your vaginal flora. Healthy vaginal pH levels range from 3.5 to 4.5, but your “normal” can change with time and age. When your pH balance levels increase suddenly, bacteria and yeast are more easily able to survive in the vaginal canal – creating lots of unpleasant symptoms, like itching, burning, and odor, or even causing an infection. 

pH balance. It’s a term we see thrown around all the time in reference to vaginas. You’ve probably encountered “pH-balanced” intimate wash, wipes, and lube at the drugstore or come across supplements that claim to support “healthy pH” for women. But what does this term actually mean? And why is it important?

Sure, you might be able to recall from your high school chemistry class that pH has something to do with the acidity of a substance – or maybe you worked at your neighborhood swimming pool and remember using pH test strips to test and balance the water. Turns out, those pool water test strips aren’t all that different from the ones that your doctor or OB-GYN might use to test your vaginal pH.

If you’re curious about what vaginal pH is, what affects it, and what it has to do with your overall health, you’re in the right place. Read on to learn more about this mysterious indicator of vaginal wellbeing, including how to test it for yourself and what to do if you’re experiencing symptoms (like itching, burning, or funky vaginal discharge) that might indicate an out-of-whack pH balance. 

First things first: What is pH? 

pH level is a measurement of how acidic or alkaline a substance is. You can measure the pH of pretty much anything: water, grape juice, battery acid, urine… you name it. Every substance will have a pH that falls somewhere along the pH scale, which goes from 1 to 14. 

If pH measures low on the scale (pH1), it means the substance is very acidic; if it measures high on the scale (pH7), the substance is very alkaline.

You’re probably pretty familiar with acids: Citrus, like lemon juice, is acidic. You may be less familiar with alkaline things, but these tend to be soapy substances, like baking soda or liquid drain cleaner. pH7 (right at the middle of the scale) is completely neutral – neither acidic or alkaline – like pure, distilled water. 

So, pH is all about acidity, or the lack thereof. But what is it, really? In scientific terms, pH is just a measure of the relative amount of free hydrogen and hydroxyl ions in the water. A substance that has more free hydrogen ions is acidic, whereas a substance that has more free hydroxyl ions is basic.

What does pH have to do with your vagina? 

As most vagina-owners are well aware, the vagina has a lot of fluid. This is most often evidenced by the discharge that sometimes pays a surprise visit to our underwear. 

Vaginal fluid is made up of a whole bunch of different substances: Cells shed by the cervix and vaginal walls, bacteria, water, mucus, electrolytes, and proteins (i.e. secretory immunoglobulin A).1 Some of the bacteria is “good” bacteria, like Lactobacilli.2 All together, you have your magical and wonderful vaginal secretions, working to keep your vagina clean and your reproductive system healthy. 

Like all other bodily fluids, your vaginal secretions (and internal vaginal ecosystem) have a particular pH level. This pH level can fluctuate day by day as the result of a LOT of different factors. A “normal” vaginal pH level is, in general, between 3.5 and 4.5.3 However: Your normal may not be the same as someone else’s normal, and your “baseline” vaginal pH often changes as you age.

Let’s revisit that number for a sec. pH3.8 is pretty acidic! It’s on par with apple or orange juice (apple juice has an approximate pH of between 3.35 and 4; orange juice ranges from 3.3 to 4.2.) Researchers have speculated that the acidity of vaginal secretions is by design. We’ll spare you the technicalities, but the general gist is this: 

Most “bad” bacteria (the kind that causes bacterial infections) cannot thrive in an acidic environment. Acidic vaginal secretions, therefore, help prevent pathogenic microorganisms from running amuck and causing infections that make their way into the cervix or uterus. Such infections, especially prior to modern medicine, could be deadly. 

The vagina’s pH needs to be acidic enough that it maintains its antiseptic qualities, but not so acidic that it kills off sperm when you’re trying to get pregnant (more on this in a bit). 

How does the vagina stay acidic & maintain a healthy pH?

Remember that “good” bacteria we mention above, Lactobacillus? It’s a microbe that actually helps keep the vagina in its acidic, healthy state by producing lactic acid as a byproduct of its glucose (or glycogen) metabolism. 

In simpler terms? Lactobacilli eat glycogen, digest it, and poop it out as lactic acid. 

So, theoretically, the more glycogen you have to feed the Lactobacilli, the more lactic acid is produced, and the lower (and healthier) your vaginal pH will be. Keep in mind that this assumption is hugely oversimplified and that there’s still so much that the medical community doesn’t know or fully understand about vaginal microbiota.

Not all vaginas are colonized with Lactobacilli – some have colonies of other, similar acid-producing bacteria like Atopobium, Megasphaera, and/or Leptotrichia.2 But Lactobacillus-produced lactic acid is the most widely accepted, studied, and discussed vaginal “acidifier.”

Let’s circle back to the glycogen, the food source for the Lactobacilli. Glycogen is produced by your vaginal and cervical epithelial cells.3 The amount of glycogen present in your vaginal “ecosystem” varies widely from person to person. Before puberty and after menopause, it tends to be low, meaning you’ll probably have less lactic acid in your vagina and thus a higher pH during those stages. 

Some researchers have hypothesized that levels of the hormone estrogen, when elevated, increase the amount of glycogen deposited in the vagina.4 Newer studies, however, haven’t been able to confirm this correlation.3 

There’s still a lot of ongoing debate about what affects glycogen levels, whether or not estrogen or progesterone have anything to do with it, and why it varies so much across individuals. We’ll keep you updated as we learn more!

What happens when your vaginal pH is off-balance?

When your vaginal pH levels are thrown off – in particular, when your pH levels increase to 4.5 or higher, becoming less acidic – your vagina starts to look like a more appealing home for things like bad bacteria or parasites. Then, vaginal odor, discomfort, and infections can start to creep in. 

All microorganisms prefer a neutral pH for optimum growth, but some bacteria can still survive and grow in more acidic pH values, like the Lactobacilli that help keep your vagina acidic. Most unhealthy microorganisms, however, stop growing at a pH of around 5.0. So it makes sense that a lower pH is generally better for your vagina. 

BACTERIAL VAGINOSIS

When your vaginal pH is too high, populations of unhealthy anaerobic bacteria like Gardnerella vaginalis and Prevotella, Peptostreptococcus, and Bacteroides tend to increase (don’t worry, we have no idea how to pronounce them, either). These are the bacteria that most commonly cause bacterial vaginosis, a.k.a. BV – the most common vaginal infection among uterus-havers of childbearing age.5 

BV has symptoms similar to that of a yeast infection – itching, burning, and a funky smell – but its signature flourish is thin, grayish vaginal discharge. The odor is notably fishy and the infection may also cause pain or burning during urination.6 If you think you may have BV, give your healthcare provider a call: Sometimes, it’ll go away on its own, but your doctor may also prescribe antibiotics for a persistent case. 

TRICHOMONIASIS

A too-high vaginal pH may also make you more susceptible to trichomoniasis (“trich”), an STI caused by a tiny parasite called vaginalis trichomonas. Like the other microscopic intruders that cause BV, trichomonas survives more easily in alkaline environments, and studies have found a strong link between vaginal microflora with high proportions of anaerobes and instances of trichomoniasis.7

While BV is not necessarily sexually transmitted – other than the fact that healthy sperm can increase vaginal pH and thus increase the risk for BV – trichomoniasis is only transmitted through sex (penis + vagina or vagina + vagina, according to the CDC). If you’ve had it, you’re not alone: It’s the most common STI and is also easily treatable with either metronidazole or tinidazole, both of which are oral antibiotics.8

Keep in mind that, for 70% of infected individuals, trich causes no symptoms. Another reason to get tested regularly if you’re having unprotected sex (no shade!). Those who do experience symptoms usually report itching, buring, pain during urination, or a change in vaginal discharge. Having trich does increase your risk for contracting other STIs like HIV, so it’s a good idea to get treated right away if you test positive.8 

CAN VAGINAL pH GO TOO LOW?

Good question! It’s unlikely, unless you’re sticking a highly acidic substance up there (like apple cider vinegar), which is definitely a bad idea. 

If, for some reason, you find that your vaginal pH is unusually low after testing it at home or with your provider, keep in mind that it could impact your fertility. Too acidic, and sperm have a much lower chance of survival! Talk to your healthcare provider to learn more. 

Vaginal pH & yeast infections

Contrary to popular belief, there’s no direct, proven correlation between vaginal pH and yeast infections. Several studies have been published on the subject, and none have found that a more acidic vaginal microbiome (with more lactobacilli, and therefore more lactic acid) inhibits the ability of Candida albicans – the fungus that causes yeast infections – to survive.9 10

C. albicans (and its cousin, C. glabrata, which can also cause yeast infections) is a pretty tough species. It resists treatment and often pops right back up if even a handful of survivors hang in there after your latest round of Monistat. That’s why yeast infections can be so annoyingly persistent. 

If you get lots of yeast infections, don’t assume your vaginal pH is off balance! Talk to your doctor to get a better idea of what the root cause might be. 

What affects vaginal pH balance?

Things that can affect your vaginal pH balance include but aren’t limited to:

Antibiotics. If you’re taking antibiotics for something like a sinus infection, they might not just be killing the bacteria in your sinuses, or wherever they were prescribed for: They can actually end up wiping out some of that good bacteria in your vagina, the lactobacilli.  

If you’re on antibiotics for something non-vagina-related, remember to balance your system out by ingesting more probiotic foods. Cultured yogurt (not the sugary kind), kefir, kimchi, and sauerkraut all contain lots of probiotics, a.k.a. the good bacteria your body needs to maintain a healthy gut and vaginal microbiome. 

You can also take probiotics in pill form, but ask your doctor for a recommendation: Not all brands are created equal! The best probiotics supplements tend to be the ones that require refrigeration and that have a shorter expiration period (it means they’re fresher and more effective). 

Your period. Yup, another reason to *strongly dislike* your period: It can screw up your vaginal pH. This is because blood has a pH of 7.4, a whole lot higher than your vagina’s “neutral” state. So, when you menstruate, your pH levels increase – up to an average of 6.6 on cycle day 2, according to one study.11

Menstrual hygiene products may also impact the vaginal microbiota – especially those that absorb rather than collect menses, like tampons (which hold blood inside your vagina for longer than your body intended). These tend to further disrupt your vaginal pH and encourage bacterial growth. 

This is part of why it’s so important to change tampons every 4-8 hours. Menstrual blood naturally contains a certain amount of “bad” bacteria; normally, it’s shed from the body right away. If it stays within the vagina for too long, that bacteria grows and may start to release higher quantities of toxins – like the ones that cause Toxic Shock Syndrome (TSS).12

Avoid bacterial infections by changing your tampon frequently or by choosing alternative period products (like a menstrual cup or menstrual disc) made from materials that are biologically inert (like medical-grade silicone or polymers). Keep in mind that even menstrual cups and discs should be changed at least every 12 hours, or however often is recommended by the manufacturer. 

Hormonal fluctuations. Remember how your vagina stays acidic? That it has to do with lactobacilli, and the food source for the lactobacilli – glycogen? Well, we still don’t know exactly how hormonal fluctuations impact glycogen production, but there’s a definite correlation between estrogen and lactic acid (the byproduct of the lactobacilli’s consumption of glycogen).4

We do know that hormonal fluctuations impact vaginal pH by changing certain conditions within the vagina: the amount and viscosity of vaginal secretions, the glycogen content, and the vaginal oxygen carbon dioxide levels, just to name a few. We also know that lower estrogen usually correlates with an increase in vaginal pH.13

Estrogen levels change throughout your menstrual cycle, peaking right around ovulation and then dropping off during the luteal phase, before your period. However, estrogen can be influenced by a number of other factors, including menopause, pregnancy, prolonged stress, and certain health conditions. So, if your vaginal pH is out of whack, it could have something to do with hormonal changes. 

Douching or deodorizing. Like we mentioned before, your vagina is a smarty. It can self-clean and doesn’t need to be douched, cleansed with scented or deodorizing soaps, or “sterilized” with anything. Rinsing with water should be enough, but if you insist on washing up, choose all-natural, mild cleansers that are diluted with water and OB-GYN-approved. 

In short: Never put any substances up your vagina without consulting your provider, first, and NEVER, EVER douche. You’ll just end up killing off all those valuable, hard-working lactobacilli – and then have to suffer through an itchy, smelly case of bacterial vaginosis as a result. 

Semen. Penis-in-vagina (PIV) sex that ends with ejaculation – i.e. the release of semen within the vagina – is another common cause of imbalanced vaginal pH levels. According to the World Health Organization, the typical pH of liquefied semen is between 7.2 and 8.0.14 This is significantly higher than your vagina’s average pH of 3.5 to 4.5. 

So, it makes sense that introducing alkaline sperm to your acidic vaginal microbiome tends to throw off vaginal pH balance, though usually only temporarily. To avoid bacterial overgrowth from the elevated pH after PIV sex, use condoms, shower and/or pee after your partner finishes, and let gravity do its thing. 

Falling asleep right after sex means sperm stays in there longer, so it’s not a bad idea to move around a bit or even utilize one of the new-fangled semen-remover devices on the market (like this sponge from Awkward Essentials) before passing out.

How to test vaginal pH levels

There are two ways to test your vaginal pH: At home or at a healthcare facility, like your OB-GYN’s office. At-home tests are, in most cases, just as reliable as the ones you’d get done with a provider. They’re relatively inexpensive and easy to use. Just search on Amazon or stop by your local drugstore; even Monistat makes a “Vaginal Health Test” that measures your pH levels. 

When to talk to your provider

If you experience any of the symptoms below, it’s a good indicator that you vaginal pH is off balance. Give your healthcare provider a ring to figure out what’s going on if you’re suffering from:

  • Itching
  • Burning
  • Inflammation or swelling
  • Abnormal odor (fishy, cheesy)
  • Unusual discharge (greenish, grayish, chunky, watery)
  • Pain with urination
  • Pain with sex

Key takeaways

Hopefully, by now you have a better idea of what vaginal pH balance is and what affects it. Here’s a quick recap of everything you need to know: 

  • Normal vaginal pH is typically between 3.5 and 4.5 – so it’s on the acidic side of the pH scale (where pH 7 is neutral, like water)
  • The main reason your vagina stays acidic is due to the presence of “good” bacteria called lactobacilli which eat glycogen (secreted by your vaginal walls), digest it, and poop it out as lactic acid
  • When your vaginal pH gets too high (i.e. too alkaline), your risk for infection, such as bacterial vaginosis (BV) or trichomoniasis (an STI), increases
  • There are many possible triggers for imbalance, out-of-whack vaginal pH, including taking antibiotics, being on your period, hormonal fluctuations, pregnancy, douching or deodorizing, and the presence of semen inside the vagina
  • Talk to your provider if you are experiencing any itching, burning, or swelling around the vagina or labia, any unusual odor or discharge, or pain during sex or urination: These could be signs of a bacterial infection (partly resulting from imbalanced vaginal pH)

Want to learn more about how to rebalance your vaginal pH (or maintain a healthy balance) on your own? We have a new post dedicated to the topic coming soon: Subscribe to our newsletter so you don’t miss out!

This article is informational only and is not offered as medical advice, nor does it substitute for a consultation with your physician. If you have any gynecological/medical concerns or conditions, please consult your physician.

© 2021 The Flex Company. All Rights Reserved.

References (Click to open/close)

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