Articles, Blog


September 1, 2019

Around six months ago I made a video going
over the different types of sex lubricants and their uses. I talked a little bit about
questionable ingredients in that video, but today I really want to get into the science-y
side of lubricant safety, specifically the issues of osmolality and pH. There’s a lot
to learn, but I’m going to try to keep it really simple and just basically introduce
to common causes of irritation and how to avoid them. Osmolality is sometimes referred
to as the “concentration” of a solution. It’s the measure of dissolved particles per unit
of water. The osmolality of a water-based or hybrid lubricant is super important because
it can affect the homeostasis of your nether regions’ mucous membranes. It’s a hydration
issue, basically. If something has a lower osmolality (i.e. a higher concentration of
water) than your body’s natural cells, then your cells are going to pull water from it.
Too much water, and your cells can actually rupture. And if something has a higher osmolality
than the body, it’s going to pull water FROM your cells, dehydrating and potentially killing
them. A study published in 2008 in the American Sexually Transmitted Diseases Association’s
official journal found that the osmolality of a lubricant is closely linked to its potential
for mucous membrane irritation. Hypoosmotic lubricants, with a lower osmolality than the
body, caused negative mucus production in test subjects, while hyperosmotic lubricants
caused irritation and tissue damage proportional to their level of osmolality, up to “severe
damage” from the worst offender – Astroglide. A 2006 study conducted by a research team
led by Craig W. Hendrix, a clinical pharmacologist at Johns Hopkins, found that hyperosmotic lubricant
ID Glide caused significant rectal tissue damage in humans and may actually increase
susceptibility to HIV and other STIs. For comparison purposes, the average osmolality
of vaginal mucus is between 260 and 290 mOsm/kg, while human semen is between 260 and 380.
The osmolality of popular commercially-available lubricants, on the other hand, is often over
2000, even surpassing 10000 mOsm/kg. Isosmotic lubricants, which are similar to the body’s
natural osmolality, have been found to be the safest, causing little to no change in
the mucous membranes of test subjects. Now, what does that mean for a consumer? Obviously
most of us can’t test the osmolality of our lubes ourselves, so how do we know what’s
safe to use? Well, the first step is to learn what ingredients are typically found in hyperosmotic
lubricants. The two biggest ones are propylene glycol, a petrochemical, and glycerin, a sugar
alcohol that acts as a humectant. Just seeing one of those ingredients on a lube package
is an immediate indication that the product is likely hyperosmotic, and most widely-available
lubricants contain both. So that’s not great. Brands that come closest to ideal osmolality
include Good Clean Love, Sliquid, and Aloe Cadabra. I’m sure there are others, but unfortunately
a lot of brands haven’t been tested or haven’t publicized their osmolality, so I don’t have
numbers for them. If you’ve ever taken a chemistry class, you’ve probably heard the term pH,
which is the measure of the acidity or basicity of a solution. Various areas of the body have
different pHs, and the body regulates all this itself with a balance of natural bacteria,
fungi, and body secretions. A balanced pH is important to avoid infection, but foreign
substances can throw it off balance. That’s one of the reasons that you’ll hear that you
shouldn’t use soap inside of the vagina. It can cause a pH imbalance, which can lead to
a yeast infection or bacterial vaginosis. Water-based and hybrid lubricants can do the
same thing. Vaginal pH tends to fluctuate between 3.8 and 4.6 or a little bit higher
depending on the circumstances. The pH of rectal fluids tends to be between 6 and 8.
It’s best to use a lubricant that’s similar in pH to the area you’re using it in. Too
acidic and the lube can sting. Too basic and it can cause a bacterial infection. Unfortunately,
lube pH also doesn’t tend to be very publicized. Lubes with a pH in the range of vaginal safety
include, again, most Sliquid lubes, Good Clean Love Almost Naked, Aloe Cadabra, as well as
Yes and Blossom Organics brand. Lubes in the rectal pH range include many of the lubes
in Sliquid’s Organics line as well as Earthly Body’s Waterslide. I’m going to link a really
great chart from a presentation by Sarah E. Mueller from Smitten Kitten that lists the
pH values of about 50 different lubricants as well as their similarities to vaginal and
rectal pH down in the description. There’s a lot to learn about lube, and this video
is only the very tip of the iceberg. I highly recommend checking out Smitten Kitten’s
for even more information. I’ll link that in the description as well. I really hope
this was helpful and simple enough to understand. Let me know any thoughts or questions you
have down in the comments, and I’ll see you next time.

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