pH balanced lube, and which bottles hit the number.

A pH balanced lube is one that measures close to a healthy vagina, 3.8 to 4.5, with the WHO putting the target at about 4.5. On our index, Sliquid Organics Natural (4.0 to 4.4), Pjur Aqua (4.1 to 4.7) and Good Clean Love Almost Naked (4.7) are the lubes that land on or near it.

Why the vagina is acidic.

The vagina runs acidic on purpose. Lactobacilli, the bacteria that dominate a healthy vaginal environment, produce lactic acid, and that acid keeps the pH between 3.8 and 4.5. The low pH is a defense. Yeast and the bacteria behind bacterial vaginosis grow less well in it. When the pH drifts up, for reasons like menstruation, semen, antibiotics, douching or menopause, those organisms get an opening.

The rectum is different. It sits near neutral, around pH 7, with no acid barrier to match. That is why a lube for anal use does not need to be acidic, and why the WHO gives two different targets.

What the WHO says.

The 2012 WHO/UNFPA/FHI360 advisory on lubricants states that a healthy vagina has a pH of 3.8 to 4.5 and that a vaginal lubricant should ideally sit at about 4.5. It notes that the rectum is near pH 7. It also says, in the same document, that osmolality should ideally be 380 mOsm/kg or under and never over 1,200. The two numbers go together.

What pH balanced on a label means.

Nothing you can verify. There is no rule about who gets to print it. A lube can say pH balanced and measure anything. The only sources for the real number are the FDA 510(k) filing a manufacturer submits to sell a lubricant in the United States (collected by Weaving Voices) and peer reviewed lab measurements like the ones Edwards and Panay compiled. Our index pulls from both. If a product publishes nothing, we do not list it.

Which lubes hit the number.

Every water based product on our index, with its published pH and osmolality, because the second column decides as much as the first.

Product	pH	Osmolality (mOsm/kg)	Read
Sliquid Organics Natural	4.0 to 4.4	106	In range on both
Pjur Aqua	4.1 to 4.7	500 to 625	pH on target, osmolality above the ideal
Good Clean Love Almost Naked	4.7	240 to 269	pH a touch above 4.5, osmolality ideal
YES VM (moisturizer)	4.15	250	In range on both
#LubeLife Water Based	3.6 to 4.5	600 to 700	pH in range, osmolality above the ideal
K-Y Jelly	4.55	2,007 to 2,510	pH on target, osmolality over the ceiling
Astroglide Liquid (original)	4.0	6,113 to 8,064	pH in range, osmolality the highest published
Coconu Water Based	4.0 to 5.0	42 to 46	Wide FDA range, osmolality lowest on the index
Bloomi Smooth	4.0 to 5.0	110 to 140	Wide FDA range, osmolality ideal
Hallelubeyah Organic Aloe	4.0 to 5.0	50 to 180	Wide FDA range, osmolality ideal
Astroglide Glycerin and Paraben Free	3.5 to 5.5	230 to 300	Very wide FDA range, osmolality ideal
Astroglide Ultra Gentle Gel	3.5 to 5.5	200 to 300	Very wide FDA range, osmolality ideal
Desert Harvest Aloe Glide	4.5 to 5.8	300 to 400	pH runs high, osmolality at the edge
Replens (moisturizer)	2.5 to 3.5	1,200 to 2,011	pH below the range, osmolality high

A note on the ranges. A single number (4.7 for Almost Naked, 4.55 for K-Y) is a lab measurement. A range like 3.5 to 5.5 is what the manufacturer told the FDA its product would fall within, and manufacturers set those ranges wide on purpose. A narrow range tells you more than a wide one.

pH is the second number.

K-Y Jelly has a pH of 4.55, about as close to the WHO target as a lube gets. Its osmolality is 2,007 to 2,510 mOsm/kg, over the WHO ceiling. The original Astroglide Liquid has a pH of 4.0 and an osmolality of 6,113 to 8,064. Both would pass a pH only test, and both are the two we tell people to skip. Pjur Aqua is the gentler version of the same lesson: pH right on target, osmolality of 500 to 625, which is under the ceiling but above the ideal.

The reverse is less of a problem. Good Clean Love Almost Naked measures 4.7, a touch above 4.5, and iso-osmolar at 240 to 269, and it was one of two products in the Dezzutti study that caused no tissue damage. A lube slightly above the pH window with a perfect osmolality is a far better bet than the other way around. If you want both numbers inside the lines, Sliquid Organics Natural is the one.

Anal use.

The rectum is near pH 7, so there is no acid environment to protect, and pH balanced is not a useful claim there. Osmolality matters more. The WHO notes that the damaging effect of high osmolality lubes may be greater with rectal use. Silicone lube has no osmolality at all, which is one reason it is popular for anal sex.

What a lube cannot fix.

A pH balanced lube will not treat an imbalance that is already there. Persistent itching, odor, unusual discharge or burning are signs of something, often bacterial vaginosis or yeast, and both are diagnosed and treated by a clinician, not by a bottle. If a lube seems to set these off, switch to one with good numbers in both columns and see whether it changes. If it does not, get checked.