The best lube for women, graded by the numbers.

The best lube for most women is a glycerin free, water based lube with an osmolality under 380 mOsm/kg and a pH near 4.5. Good Clean Love Almost Naked is the one that hits every mark, feels like nothing, and costs about the same as the drugstore bottle that fails the test.

How we ranked these.

Two numbers decide most of this list, and neither one is on the front of the bottle.

Osmolality is how concentrated a lube is compared with your own tissue. Vaginal secretions sit around 260 to 290 mOsm/kg. A lube far above that pulls water out of cells, which is the mechanism behind the sting, the drying out an hour later, and in lab studies, damage to the tissue lining. The WHO advisory on lubricants says 380 or under is ideal and sets 1,200 as the ceiling. Most famous brands are over the ceiling.

pH is how acidic it is. A healthy vagina runs 3.8 to 4.5. A lube near 4.5 is on target. One that runs 7 or 8 is not a disaster, but it is working against you.

We only list products that publish those numbers, either in FDA 510(k) filings or in peer reviewed lab measurements. Then we use them. The full ledger, with every product graded, is the lube index.

Which one for which situation.

• You want one bottle and you do not want to think about it. Good Clean Love Almost Naked. It is the benchmark for a reason: the numbers are right, it is sold everywhere, and the aloe base does not go tacky.
• Sensitive skin, or you have been irritated by lube before. Astroglide Ultra Gentle (a gel that stays put) or Sliquid Organics Natural (thinner, lowest osmolality of the mainstream brands). Both are glycerin free and fragrance free.
• Pelvic pain, vestibulodynia, or a pelvic floor therapist on your team. Desert Harvest Aloe Glide is the one most pelvic PTs name. Coconu Water Based has the lowest osmolality on our index at 42 to 46.
• Menopause, breastfeeding, or dryness that is there every day. Start a moisturizer, not a lube. YES VM has the best numbers of any moisturizer we track (250 mOsm/kg, pH 4.15). Replens is the one gynecologists reach for first. Use either every two to three days, then add Uberlube or Almost Naked during sex.
• Showers, baths, long sessions, or you hate reapplying. Uberlube. Silicone does not evaporate and a few drops go for an hour. Not for silicone toys, which is the one real caveat.
• You are at a drugstore and need something tonight. Astroglide Glycerin and Paraben Free or Ultra Gentle. Not the blue bottle. See the next section.

The two we would skip.

K-Y Jelly and the original Astroglide Liquid are the two best known lubes in America and the two with the worst published numbers. K-Y Jelly measures roughly 2,000 to 2,500 mOsm/kg in lab tests. Astroglide Liquid measured 6,113 in one study and 8,064 in another. The WHO ideal is 380. Neither is unsafe in the sense of being toxic. Both are the reason a lot of people think they are "sensitive to lube" when what they are sensitive to is a lube that is twenty times saltier than they are.

The fix is cheap: Astroglide's own Glycerin and Paraben Free version measures 230 to 300.

What about flavored, warming and tingling lubes?

Skip them for vaginal use. Warming and cooling effects come from high levels of glycol, menthol or similar, and the FDA filings for those products show osmolality in the 950 to 2,800 range. The same brands' plain versions are usually far better. If you want flavor for oral sex, it is fine, but wipe it off before penetration.

A note on "natural" lube.

Coconut oil, olive oil and aloe straight from the plant all get asked about. Oils feel great and are fine with silicone toys, but they break latex and polyisoprene condoms and can linger in the vagina longer than water based products. Pure aloe is close to a real lube and the base of several products on this list. We cover each one in Basics.