Vaginal pH balance: what's normal, what upsets it and how to keep it balanced
Most of us never think about vaginal pH. Then something feels or smells different and the internet is full of washes, gummies and test kits that claim to fix it. This post explains what a normal vaginal pH is and why it changes. It also covers what helps, and what makes things worse.
What is a normal vaginal pH?
In the reproductive years, a healthy vaginal pH is usually below 4.5. It's often between 3.8 and 4.5. That's moderately acidic. Water, for comparison, is 7. You'll see slightly different ranges online, from 3.8 to 4.2 up to 3.8 to 5.0. That's partly because pH changes with age and the time of the month. Studies also measure it in different ways. UK clinicians use 4.5 as the cut-off. Before menopause, a reading above 4.5 can be a sign of bacterial vaginosis (BV).
After menopause the picture changes, and a higher pH is normal. We explain why below.
Why is the vagina acidic?
The acid comes from the vaginal microbiome. That's the community of bacteria that live in the vagina. In most people of reproductive age, Lactobacillus bacteria dominate. They feed on glycogen, a sugar stored in the vaginal lining. They turn it into lactic acid. The acid keeps the pH low. That makes it harder for other microbes to take over.
Oestrogen keeps this system running. It keeps the vaginal lining thick and stocked with glycogen. Oestrogen falls while breastfeeding and after menopause. Then Lactobacillus has less to eat. Their numbers drop and the pH rises. That's one reason dryness, irritation and urine infections become more common after menopause. We explain more in Low oestrogen symptoms: why your vulva and vagina get dry.
pH also shifts for short spells in everyday life. Period blood and semen are both less acidic than the vagina. So pH rises a little during a period and after sex without a condom. Then it settles again.
What does a normal vagina smell like?
A healthy vagina has a smell. It's usually mild and slightly sour or musky, and it can change through your cycle, after exercise and after sex. Normal discharge is clear or white and doesn't have a strong smell or colour.
Not every smell comes from the vagina. The vulva is skin, with sweat glands and hair, like your armpits. Sweat, tight clothes or a hot day can make it smell stronger. That has nothing to do with your vaginal pH.
Some changes are worth checking. Look out for a sudden strong or bad smell, especially a fishy one. Also watch for discharge that changes colour, texture or amount.
Smell or discharge changed? BV, thrush and trichomoniasis
Bacterial vaginosis (BV) happens when other bacteria outnumber Lactobacillus. The pH then rises above 4.5. BV is the most common cause of a fishy smell. The typical sign is thin grey or white discharge with a strong fishy smell. It's often more noticeable after sex. BV doesn't usually itch.
Thrush is different. It usually itches and feels sore. The discharge is thick and white, with little smell. Trichomoniasis is a sexually transmitted infection. It can cause a frothy yellow or green discharge with an unpleasant smell. Each of these needs a different treatment. So if your discharge or smell changes, don't guess. Get it checked by a GP or sexual health clinic. The NHS page on bacterial vaginosis explains diagnosis and treatment.
Home pH test strips are easy to buy. They can show a raised pH. But they can't tell you the cause. It could be BV, trichomoniasis or the normal rise after menopause. A clinic can tell the difference.
How can I balance my vaginal pH naturally?
The honest answer? A healthy vagina looks after its own pH. What you avoid matters more than anything you add. The NHS says perfumed products in or around the vagina make BV more likely. NHS sexual health guidance advises against douching and washing too often. It also advises against bubble baths, scented soaps, antiseptics and feminine washes. Avoiding strong detergents for your underwear helps. So does not smoking.
If your pH has risen because of low oestrogen after menopause, vaginal oestrogen treats the cause. See Vaginal dryness treatment: menopause, perimenopause, POI and after giving birth [add link when published].
Supplements and pessaries sold as "pH balancing" are mostly probiotics. The evidence for them is mixed. See Do vaginal probiotics work?. For food, see Can diet change your vaginal microbiome? 
Do I need a pH-balancing wash?
No. The vagina cleans itself, and nothing needs to go inside it. Many intimate washes are sold as pH-balanced, but pH is only part of the picture. Most foaming washes contain detergents (surfactants), and many contain fragrance. Both can strip the skin's natural oils and irritate the vulva, whatever the pH.
The vulva, the outer skin, is a different matter from the vagina. It's skin rather than lining, and it has its own mix of microbes. A 2025 Dutch study of 58 healthy women aged 22 to 82 found that about a quarter had mainly skin bacteria on their vulva, about a fifth mainly vaginal bacteria, and roughly half a mix of the two. UK dermatologists say wash the vulva once a day at most. Use water, or a plain emollient instead of soap. Skip perfumed washes, wipes and sprays. If the skin feels dry, a plain, unscented ointment can help.
The short version
Much of what’s written about vaginal pH runs well ahead of the research. A lot of it comes from people selling things. We sell things too, so read us with the same healthy suspicion. That’s why we link to our sources. Here’s what we know for sure. Lactobacillus and oestrogen keep the vagina acidic. A higher pH is normal after menopause. Before menopause, it can be a sign of BV. Fragranced products, washes and douches make things worse. If your smell or discharge changes, get it checked rather than covering it up.
References
West of Scotland Sexual Health MCN, "Bacterial Vaginosis Guideline," (June 2025) https://www.wossexualhealthmcn.scot.nhs.uk/wp-content/uploads/2025/12/WOS-BV-Final-2025_June-version-6.4.pdf
NHS, "Bacterial vaginosis," (reviewed June 2026) https://www.nhs.uk/conditions/bacterial-vaginosis/
nidirect (adapted from NHS content), "Vaginal discharge," (updated June 2026) https://www.nidirect.gov.uk/articles/vaginal-discharge
British Association of Dermatologists, "Care of vulval skin," Patient Information Leaflet (updated May 2023) https://www.skinhealthinfo.org.uk/condition/care-of-vulval-skin/
Mieremet A, et al., "Taxonomic and functional profiling of the vulvar microbiome indicates variations related to ecological signatures, aging, and health status," Frontiers in Microbiology (September 2025) https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1633147/full