Bad bacteria tend to make your vagina less acidic, which might sound good (who wants an acid vagina?) but it’s not good. Your vagina should be, in chemistry terms, acidic – just a little more acidic than vitamin C. This doesn’t mean your vagina will burn – far from it.

Some context of the pH of different parts of your body and substances

  • Water is neutral at a pH of 7
  • Skin is slightly acidic with a pH of 5.5
  • Saliva is neutral between 6.5 and 7.5
  • Stomach acid has a pH of between 1.5 and 4.0
  • A healthy vagina has a pH of between 3.5 and 4.5
  • An unhealthy vagina has a pH of over 4.5

Don’t worry about the term ‘acidic’, and try to avoid associating the popular concept of ‘alkalising your body’ with an alkaline vagina. These ideas are very different and cannot be linked. An acidic vagina is desirable.

The pH scale goes from 0 – 13. The lower the number, the more acidic.

Boric Acid Vitamin C Vagina pH

What happens when your vagina becomes more alkaline

When your vagina becomes more alkaline (higher numbers above 4.5), it means the wrong bacteria are present and are trying to take over, producing substances that cause a deliberate change in pH to more alkaline. This change in pH is to increase their comfort levels, like turning the air conditioning on, for example, on a hot day. Bad bacteria like it cold, good bacteria like it hot.

What that means is your lactobacilli, the healthy, friendly bacteria that make your vagina acidic, can’t survive and what’s known as vaginal dysbiosis occurs. Dysbiosis means microbially out of order, not quite right. It isn’t a disease in and of itself, but a state of altered and unhealthy microflora.

Why lactobacilli are good for your vagina

Lactobacilli produce lactic acid as part of their normal daily lives, in the same way that we produce carbon dioxide when we exhale.

Lactobacilli eat lactose (a sugar found in milk) and other sugars, and then use the sugars in exactly the same way we do: as energy to survive and reproduce.

Lactobacilli are the same type of bacteria that turn milk into yoghurt (acidophilus). This might seem gross, but this is why you can make yoghurt out of healthy vaginal secretions! Lactobacilli don’t create bad smells, though the sour smell of fresh natural yoghurt can make the mouth water and be unpopular with some of us.

Bacteria make all kinds of smells, because they produce gases and byproducts as part of their lifecycle. A fart, for example, is a gas byproduct of our digestion, caused by – you guessed it – bacteria!

Testing your vaginal pH at home quickly, cheaply and easily

You can test your vaginal pH quickly and easily at home with cheap pH strips from the pharmacy or online. You do not need fancy equipment or special expensive pH strips for this. pH testers are all based on the same principle, which most of us have done in science class with litmus paper. pH strips are very cheap, so don’t get sucked into paying a lot for ‘special’ pH strips.

It can be useful to get pH strips that go in .5 increments to get a more accurate result, and to try a few brands to make sure they are all saying the same thing. This is extra important if you are trying to treat a vulvovaginal condition where pH is one of your indicators of health.

Generally pH testers ranges from 0-13, but you only really need between 3-7. Get a cotton tip, dip it into your vagina, then swipe the cotton tip across the coloured part of the pH tester strip. Try to get as much fluid on the cotton tip as you can. You can also use a clean finger to do this too, but remember to get enough fluid to do the test.

Don’t do the vaginal pH test when you have your period, as you will be unable to read the results. The pH strip relies on you interpreting the colour it gives you, matching it to the key on the packet to determine pH.

Understanding your vaginal pH test results

To read the results, you need to match the colour that the pH strip turns to the coloured key on the pH strips packet. Your pH strip colours may vary from the below colours, but check the numbers and colours of your pH tester kit for accurate results.

  • Normal vaginal pH is 3.5 – 4.5
  • Bacterial vaginosis or aerobic vaginosis is above pH 4.5
  • It is rare to have a pH of less than 3 or past 8 or 9, because vaginal pathogens or bacteria do not tend to produce this pH

Vaginal pH changes across your menstrual cycle

It’s important to note when you do your pH test what day of your cycle you are on. Day 1 is always (as a consistent across all medical systems) the first day of your period, so keep a period tracker and mark which days you have which pH to see if it changes.

You are likely to see changes in pH near your period and around when you ovulate. Menstrual blood and semen are both alkaline, so if either of these fluids is present, a different result is likely. The reason for the changes can be oestrogen levels. The more oestrogen you have, the more glycogen is produced, and the more food is available for lactobacilli.

If you have vulvovaginal symptoms, but a low pH (as in, acidic and healthy levels), you may have what’s known as cytolytic vaginosis, which is lactobacillus overgrowth syndrome. If this is the case, your symptoms will be cyclic and fluctuate with the food supply of the lactobacilli.

Symptoms will worsen with ovulation, and you will feel better during your period, when the more alkaline menstrual blood kills off some of the bacteria and low levels of oestrogen reduce their food supply.

Chart your pH for a few months as a good baseline while you are healthy, so if your vagina’s ph goes off, you know immediately.

How to balance your vaginal pH

Whether or not you can easily balance your vaginal pH is going to depend very heavily on what sort of microbes you have living in your vagina. Some microbes are easy to get rid of, while others not so much. You can try some easy treatments at home to get your vaginal pH back down, but if you find they are not working or only working temporarily to stop your symptoms, you are likely going to need a proper test and other treatments that are a bit more hardcore.

Remember that you could have vaginal symptoms associated with an infection, or something a bit harder to get rid of like bacterial vaginosis or aerobic vaginosis. These problems won’t respond very well to general vaginal acidifiers, but are worth a try regardless.

If you suspect you have a sexually transmitted infection, see your doctor to be tested. If you have a yeast infection, you may also find relief from symptoms using these acidifiers, but again, if symptoms are not resolved completely after a few days of using these treatments, see your doctor.

Yeast infections don’t present with pH changes, and your pH will look normal. In this case, working to balance your pH is not the goal, but to increase lactobacilli numbers.

Easy, safe vaginal acidifiers to balance your vaginal pH

  • Vitamin C – only use a small amount (about 100mg), and avoid putting a tablet into your vagina without crushing it up – it can burn and cause irritation – not for long-term use to balance your vaginal pH
  • Boric acid – 600mg in a vegetable capsule at night until symptoms resolve, but not for long-term use (up to two weeks) – read our factsheet for safe use of boric acid
  • Vinegar douche – always dilute vinegar when using as a douche, as it will burn otherwise – a few tablespoons full of vinegar in a cup of warm water can help balance your vaginal pH, any vinegar works

Remember, you may have a bigger problem than just a bit of an off-smelling or feeling vagina, so if you are failing to balance your vaginal pH, see your doctor!