Lube Matters: Part 4 – Water-Based Lube, pH, and Osmolality

Water-Based Lube

Water-based lube is the most common type of personal lubricant on the market. In this series, I’ve already covered why personal lube is important, oil-based lube, and silicone-based lube. This piece stands on its own, though. We’re going to get a bit scientific, but bear with me. I care about your health and pleasure. I also want to say that if it’s not broken, you don’t need to fix it. If you have a lube that you love, there’s no reason to stop using it unless you notice an uptick in vaginal dryness, infections, or any kind of irritation.

What Is It?

Water-based lube is mostly filtered water, with other ingredients dissolved in it to make it slick. Remember: wetness does not always equal slickness.


Water-based lube is compatible with all condoms, all body parts, doesn’t make you wash the sheets because it evaporates, and you don’t have to wash it off. It can even change the flavor of oral if you’re into flavors.


Dries Up Quickly

The #1 complaint I see about good quality water-based lube is that it stops working more quickly than other types of lube. The water has absorbed in the body and evaporates into the air, but the so the answer is to add a bit of water to reactivate the lube.

Commercial Lubes Contain Potentially Harmful Ingredients

Generally, in the US, good quality lube isn’t found at HEB or Walgreens. The commercial lubes are made as cheaply as possible, and while it doesn’t cause noticeable harm to most of the population, it’s possible that’s because people don’t know the facts. There are hundreds of water-based lube formulations out there, and they can contain allergens and other ingredients that are potentially irritating or lead to yeast infections. Here are ingredients to look out for:

  • Parabens – 10% of the population are allergic to parabens (methylparaben is the most common), causing genital irritation, and they also mimic estrogen in the body
  • Propylene Glycol – a petroleum-derived preservative linked to bacterial vaginosis,  known to cause genital irritation, and greatly increases osmolality of the lube
  • Glycerin(e) – linked to yeast infections in some users, and greatly increases osmolality of the lube
  • Polyquaternium-15 – increases HIV-1 replication
  • Sucrose, fructose, or glucose – sugar, which causes yeast infections in vaginas
  • Nonoxynol-9 – an abrasive spermicide changes the integrity of all surrounding cell membranes, kills healthy bacteria and skin cells, causes irritation, and may increase your STI risk
  • Clorhexidine gluconate – found in SURGILUBE, a lube often used for pap smears; kills everything – good bacteria, yeast, epithelial cells; increases your STI risk, including anally (It is OK to bring a quality lube with you to your gyno appointments)
  • Benzocaine – a numbing agent found in many anal desensitizing lubes that is an irritant you can’t feel, and can lead to tissue tears since you can’t feel pain
  • Organic ingredients – if you experience seasonal hay fever allergies, you may be allergic to botanical ingredients in a lube, and that includes agriculturally organic ingredients
  • Tocopherols – Vitamin E, which is a concern for those with Celiac disease because natural sources will contain trace gluten

There are dozens of other things to watch out for, incluiding things that you could potentially be allergic to. This is just a starter list, but I’m happy to help you analyze the ingredients of any lube you have via Ask DeAnn if you’re having a problem. Basically, you want your lube to have less than 8 ingredients, since the more it has, the more likely something is in there that can irritate or harm you, and the higher the chance of a wrong pH or osmolality, which we’ll talk about next.

Lube Science

Because you can dissolve just about anything in water, water is known as the universal solvent. If you’ll remember from Chemistry class, the things dissolved in the solvent are called solutes. This is important, because your body is 60% water and can absorb the lube (and its solutes). This also means water-based lube has a pH and an osmolality. These sciency words that are important, especially if you have a vagina or have unprotected sex. The pH and osmolality of a lube can affect your susceptibility to yeast infections, STI’s, and even cancer. Yikes! Lube science looks at this relationship and the relationship with the final product and your cells.


The pH of a water-based liquid is the measure of how acidic or basic it is. Using a lube that is too basic for your tissues can sting, like lemon juice on a cut.

The vagina’s pH changes over time with hormonal changes, cycle, and age, and is roughly acidic. The vagina ranges from 3.5-7 on the pH scale. A lube that’s too acidic or too basic can throw off the balance of the organisms (natural yeast and bacteria) that live in the vagina, and lead to infection.The pH of the vagina is generally higher after menopause.

The anus also has a microbiome to manage, although its less finicky, but overgrown bacteria in the anus can lead to issues. The pH of the anus is 6-7.

Here’s a handy chart of some of the more common lubes out there and their pH (click for a larger version):

Lube pH Chart (e-mail me at deanncope at mysecretsoiree dot com for a list)

Special thanks to Sarah Mueller via

One thing to note is that pH is very important when you are trying to conceive. You want a lubricant with a higher pH to help sperm survive. This is why I recommend Pre-Seed for couples struggling with fertility.


By far one of the most important aspects of a lube are how much and how many solutes are dissolved in the water. This measure is called osmolality, and it’s measured in milliOsmoles per kilogram, or mOsm/kg. The ideal osmolality for body tissues is 285-295 mOsm/kg. The World Health Organization recommends a lube no more than 1,200 mOsm/kg because after that, cells start dying. Some lubes, however, have osmolalities so high, they cause dead cells to slough off in sheets. This can lead to infections, higher STI transmission rates, and increases cell turnover, which can increase your risk for cancer. Sex educators often refer to KY Warming lubricant as “vagina poison” for this reason. This can also cause a lot of irritation, leading to microtears in the tissue. High osmolality lubes can also make you dependent on them by depleting vaginal tissue of its ability to secrete vaginal fluid components properly. Here’s a handy chart on osmolality listing some common lubes (click for a larger version):

Lube osmolality chart (e-mail me at deanncope at mysecretsoiree dot com for this list)

Special thanks to Sarah Mueller via

You can generally tell if a lube has a high osmolality by looking for ingredients like propylene glycol, glycerin, and parabens. It’s also worth noting that an osmolality that’s too low can also harm your cells, so stick to ones that are at least 50 mOsm/kg.

Why should you care?

Let’s sum up. The wrong pH or osmolality of water-based lube can harm you. The wrong osmolality can kill your cells and cause them to slough off en masse and cause vaginal dryness. The wrong pH can upset the balance of the vaginal flora. Some solutes are allergens that can give you a burning sensation. Some solutes react with the microorganisms that live in your vagina or rectum and can cause them to overgrow, leading to infection. The wrong water-based lube can put you at greater risk for STI’s or spreading one you already have. Water based lube isn’t regulated properly, either.

Wait, Doesn’t the Government Protect Us?

Unfortunately, modern lube science is light years ahead of current government standards. The US FDA does classify personal lubricants as Class II medical devices, but their data is based on very old methods of animal testing. In fact, we can test lube effects on human cells grown in a laboratory, and animal testing is no longer needed. Yet, the FDA still requires all personal lubricant manufacturers to test their products in the eyes and on the vulvas of rabbits. These tissues don’t match inside human vaginas or anuses, and there is currently no testing on human genitals at all.

There’s a fierce legal battle behind the scenes with brands who do not test their products on animals. The FDA is currently blocking the import of a popular UK lubricant, and may shut down a couple of small US brands because of the animal testing requirement. Many consumers want products that are safe for human tissues and not tested on animals, and the FDA is slow to change its rules. As you can imagine, talking about sexual pleasure and sexual health products often makes politicians uncomfortable, and in many cases, unwilling to act. If it doesn’t control a woman’s sexuality, it seems like lawmakers are unwilling to discuss it.


Brands matter when it comes to lube. Drug store brands tend to be owned by multi-national corporations that hold sway over (or have enough money to be ignored by) the FDA. My personal water-based lube is Sliquid Sassy, which is a gel lube that’s great for just about everything. I’m a fan of most Sliquid lubes, because they’re made ethically right here in Texas, and don’t contain a lot of junk. Other great brands include Good Clean Love, Blossom Organics, Intimate Earth, and Pjur.


One comment

Leave a Reply