Lubricant pH

Water-Based Lubricants & Vaginal Health

Lubricant pH

pH plays a vital role in the health of every major body system. If you have a vagina (or care about someone who does) here are some things to know about the pH of water-based lubricants and how it may impact vaginal health & fertility.

What is pH?

Potential for Hydrogen – or pH – describes how acidic or alkaline a water-based solution is.

pH is measured on a scale of 1.0 to 14.0 where 1.0 is acidic, 7.0 is neutral, and 14.0 is base / alkaline.

Every whole number on the scale represents a 10-fold change relative to its neighbors – a pH of 4.0 is 10x more acidic than pH 5.0.

Human Microbiota

Mini Ecosystems that Shape Our Health

To get at why a lubricant’s pH may matter, you need to know a little something about how a healthy vagina stays that way.

Human microbiota describes the collection of bacteria, fungi, viruses, and other microorganisms that colonize our bodies. It’s estimated that the human body has about as many of these microorganisms as skin cells.

Some of these microorganisms are communal – they don’t impact human health. Some are mutualistic – both the organism and the human benefit. And some are pathogenic or otherwise harmful to human health.

Together, these microorganisms exist as ecosystems that play a key role in the health of our digestive, reproductive, and urinary systems … just to name a few.

When we’re healthy and our ecosystems are balanced, harmful microorganisms are kept in check by beneficial ones and it’s here that pH becomes relevant …


A Vagina's Best Friend

Lactobacillus are beneficial bacteria that make up a major part of the human micorbiota – especially in the vagina and gut.

Lactobacillus accounts for 90% of the microbiota in a healthy vagina and it protects us in 2 key ways:

Vaginal cells are normally rich in glycogen. As these cells are shed, Lactobacillus convert the glycogen into pyruvic acid and then lactic acid. This cycle maintains an acidic pH that other microorganisms can’t tolerate.

Lactobacillus form a biofilm in the vagina & gut that can withstand harsher conditions than other microorganisms. This biofilm out-competes other organisms, releases anti-microbial substances, and physically blocks harmful stuff from colonizing.

Fluctuating pH

Lactobacillus work to maintain vaginal pH at an acidic 3.8 – 4.5. Anything that reduces the number of Lactobacillus or makes the vagina less acidic, increases our risk of infection. Common reasons this can happen include:

Decreased estrogen – Estrogen is a hormone that, among other things, controls the amount of glycogen in vaginal cells. As mentioned, lactobacillus need glycogen to produce the acid that protects us from harmful microorganisms. Less estrogen = less glycogen = less lactobacillus = a less acidic vagina.

Prepubescent girls and postmenopausal women have naturally lower estrogen levels. Decreased estrogen can also be caused by certain medical conditions and medications.

Menstruation – When we get our periods, the alkalinity of blood and the flushing of Lactobacillus raise our vaginal pH making it less acidic. Women who struggle with yeast or bacterial vaginosis (BV) are often fighting a monthly battle that starts with their periods and is rooted in pH.

Fertility, arousal & sperm – Sperm need an alkaline pH of 7.0 – 8.5 . To help protect sperm from the normally acidic state of our vaginas, some pretty cool stuff happens. During fertile times, when a woman becomes aroused, the pH of her cervical mucus instantly goes up so it’s friendlier for sperm. At the same time, seminal fluid instantly neutralizes vaginal pH and acts as physical protection for sperm.

If you’ve ever been itchy after sex, you may have been feeling a mini battle between microbes taking advantage of the lower acidity and Lactobacillus fighting to return things to an acidic state.

Personal care & hygiene – Any product you use in or around your vagina can affect pH. This includes douching, sexual lubricants, vaginal moisturizers, body washes, and medications.

Douching is of special concern because it’s still relatively common even though it’s linked to BV, PID, problems during pregnancy, and the transmission of STIs. Do your body a favor and only douche if your doctor recommends it.

Some Important Roles of Vaginal pH

It’s hard to overstate how amazing the human body is. Here are just a few examples of how Lactobacillus protect us and why you want to avoid things that can alter your vaginal pH as much as possible.

Candidiasis & Bacterial Vaginosis – Yeast and the anaerobic organisms that cause BV are naturally present in the vagina. They’re kept in check by Lactobacillus and the vagina’s naturally acidic state. If vaginal pH goes above 4.5 – as can happen for the reasons listed above – yeast and BV can gain a foothold and begin replacing Lactobacillus. This prevents the vagina from returning to its naturally acidic state, setting up a vicious cycle that allows more yeast and harmful bacteria to thrive.

Fertility – Sperm are at their best when vaginal pH is between 7.0 – 8.5 and there’s adequate mucus to help transport them past the cervix. A pH below 6.0 is too acidic and reduces sperm function. As mentioned above, several things happen to buffer the vagina’s natural acidity and protect sperm. Anything that prevents this buffering can impact fertility and it is theorized that improper pH plays an under-recognized role in unexplained infertility and subfertility.

HIV & Other Viruses – Studies of the heterosexual transmission of HIV show that normally acidic cervicovaginal mucus (CVM) plus the presence of lactic acid can effectively trap and deactivate HIV.

As mentioned, sperm need a more alkaline environment and several things happen during sex to lower vaginal acidity and protect sperm. Unfortunately, this buffering also gives pathogens an advantage.

In hetero sex, the risk of HIV is linked to the ability of male ejaculate to instantly neutralize vaginal pH. Additionally, women who struggle with BV are at higher risk of HIV because BV lowers acidity.

It’s theorized that methods capable of maintaining both a high lactic acid content & acidity for CVM during & after sex could significantly reduce the transmission of HIV and other viruses.

The pH of Lubricants

If the goal is to avoid things that affect vaginal pH, it makes sense to use lubricants that mimic nature as closely as possible.

Ideally, water-based lubricants should have a pH around 4.5 to support vaginal health and protect against infection … or a pH closer to 7.0 to support fertility.

If you’re concerned and want to know about a lube’s pH, you have 2 problems. First, pH isn’t disclosed on most FDA 501(k) summaries – the exception being lubricants sold as fertility-friendly. So there’s no centralized information or easy way to compare multiple products.

Second is product labeling. You’ll find lubricants with no mention of pH while others claim to be hypoallergenic, or pH balanced, or to have optimal pH. None of these terms have legal, or even widely agreed upon, definitions – they are marketing tools and provide no real information.

For example, pH balanced could mean a neutral pH of 7.0. It could also mean a pH of 5.5 to match our skin. It may even mean a pH of 4.5 to match our vaginas. To know for sure, you have to ask the manufacturer and most aren’t forthcoming. Alternatively, you could use pH test strips – we just don’t think you should have to.

From the information we found,  it appears most water-based lubricants have a pH between 4.5 and 6.0. The slight acidity works along with preservatives to prevent harmful stuff from growing.

Unfortunately, this is the exact range we don’t want – it isn’t acidic enough to support vaginal health and it’s too acidic to support sperm health.

So What's a Vagina to Do?

Considering how important it is to vaginal health & fertility, we find it hard to believe that pH is not required by the FDA or on product labels. And we find it frustrating that the industry doesn’t do more to regulate itself and promote the safest sex possible. Arghh!

In real life it’s hard to know at what point a lube’s pH becomes a problem. While the pH of most water-based lubricants isn’t optimal, it is within the range a healthy vagina experiences naturally.

While we feel it’s of general importance to all women, pH is of special concern if you’re trying to conceive,  are dealing with hormones, or already struggle with infections.

Request information – Most manufacturers have websites and contact forms that make it easy to request product information (we use them all the time). You may not get the info you’re after, but you’ll be adding to the overall demand which can help push the industry in a better direction.

If you’re not trying to conceive, consider using a condom to avoid the neutralizing effect semen has on vaginal pH.

f you are trying to conceive, consider using one of the few lubricants approved by the FDA as fertility-friendly.

Only use water-based lubricants that state their pH, or use pH paper to test your products.

Skip water-based lubricants and try silicone or plant oils instead. If you only have one lube on your nightstand, we recommend silicone for its safety, value, and effectiveness.

Our mission is to help you find safer, gentler lubricants – we hope this helps! Do you struggle with vaginal pH? Do you have any tips or products you recommend? Let us know in the comments below ?


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