Lubricants

Why lubricant matters

Friction causes microtrauma. Microtrauma causes pain, tearing, and increased susceptibility to infection, because an intact epithelium is the first barrier against pathogens. Lubricant reduces all three. It is not a signal of inadequate arousal: natural lubrication varies with cycle phase, hydration, medication, menopause, breastfeeding, testosterone use and simple anatomy, and arousal non-concordance means genital wetness tracks subjective desire only loosely (Chivers et al., 2010, meta-analysis, r ≈ 0.26 in women).

Rectal tissue produces no lubricant at all. For anal sex, lubricant is not optional.

Types compared

Silicone lubricant with silicone toys causes surface degradation; use water-based, or use a condom over the toy.

What to avoid, and why

• Nonoxynol-9. A spermicide once added to condoms and lubricants. WHO and CDC advise against it for HIV prevention: trials, including a 2002 multi-centre study in sex workers, found frequent use caused epithelial disruption and increased HIV acquisition.
• Glycerin and glycerol in high concentration. Associated with candida overgrowth in susceptible people and with epithelial changes at high osmolality.
• Chlorhexidine, parabens and strong preservatives. Associated with irritation and with disruption of vaginal lactobacilli in laboratory studies.
• High osmolality. WHO's 2012 advisory recommends personal lubricants have osmolality ideally below 380 mOsm/kg and not exceeding 1,200 mOsm/kg, and pH around 4.5 for vaginal use and 5.5–7 for rectal use. Many mass-market lubricants exceed 2,000 and some exceed 6,000 mOsm/kg. Hyperosmolar lubricant draws water out of epithelial cells; Fuchs et al. (2007) and Begay et al. (2011) demonstrated resulting epithelial damage in rectal tissue models. Iso-osmolar products are worth seeking out for frequent or anal use.
• Warming, tingling, cooling and flavoured products. Usually contain capsaicin, menthol or sugars. Sugars feed candida; the active agents commonly irritate mucosa.
• Numbing lubricants for anal sex. Actively unsafe. Pain is the signal that prevents injury; suppressing it permits tearing that is only discovered afterwards.
• Household substitutes. Petroleum jelly and baby oil break latex and are associated with bacterial vaginosis in observational work. Saliva dries fast, transmits herpes, gonorrhoea and other pathogens, and offers little mechanical benefit. Coconut oil breaks latex and evidence on its vaginal flora effects is thin.

How to use it well

Use more than seems necessary. Apply to both surfaces. Reapply during longer sessions — reapplication prevents more condom breakage than any other single behaviour. For anal, apply externally, internally, and to the inserted object, and add more repeatedly. Warm it in your hands first. Put a towel down and stop worrying about mess.

Allergy and irritation

Persistent burning, itching or swelling after use points to an ingredient reaction — most commonly glycerin, propylene glycol, parabens or fragrance — or to latex allergy from the barrier rather than the lubricant. Switch to a minimal-ingredient iso-osmolar product and see a clinician if symptoms persist, since recurrent thrush, bacterial vaginosis and lichen sclerosus present similarly.

Sources

• WHO/UNFPA/FHI360. "Use and procurement of additional lubricants for male and female condoms: advisory note." 2012.
• Fuchs EJ et al. "Hyperosmolar sexual lubricant causes epithelial damage in the distal colon." Journal of Infectious Diseases, 2007.
• Begay O et al. "Identification of personal lubricants that can cause rectal epithelial cell damage." AIDS Research and Human Retroviruses, 2011.
• Edwards D, Panay N. "Treating vulvovaginal atrophy: how important is vaginal lubricant and moisturizer composition?" Climacteric, 2016.
• Wilkinson D et al. "Nonoxynol-9 spermicide for prevention of vaginally acquired HIV." Cochrane Database of Systematic Reviews.
• Chivers ML et al. Archives of Sexual Behavior, 2010.

Last reviewed: August 2026.