Lubricant is one of the most commonly used intimate products, yet one of the least regulated. Labels are often vague, marketing claims outpace the science, and what says 'natural' doesn't always mean 'safe'. In this blog we explain which ingredients to avoid and why, with the WHO guidelines as the basis.
1. Excessively High Osmolality
What it is: osmolality measures the concentration of dissolved substances in a liquid. Vaginal and rectal mucous membranes have a natural osmolality. Lubricant with a much higher value 'draws' moisture out of mucosal cells, weakening the barrier.
What WHO recommends: maximum 1200 mOsm/kg, ideally below 380 mOsm/kg. Many popular lubricants are above 3000 mOsm/kg, well outside the safe range according to this guideline.
Why it matters: chronically weakened mucous membranes raise the risk of infections (including STIs if in play) and irritation. Read our complete lubricant guide for depth.
2. Glycerin at High Concentrations
What it is: a sweet, sugar-like substance often used as a humectant. Fine at low concentrations; a source of yeast growth at high concentrations.
Risk: for women prone to yeast infections (Candida), glycerin is a sugar source that stimulates growth. A repeating pattern of yeast infections after sex may be related to the lubricant.
Alternative: glycerin-free lubricants, often clearly labeled 'glycerin-free'.
3. Parabens
What they are: a group of preservatives (methylparaben, propylparaben, etc.) that inhibit microbial growth in products.
Risk: parabens are linked in research to hormone disruption (endocrine disruptors). The evidence is mixed and long-term effects from local application are unclear, but for sensitive mucous membranes and frequent use, caution is advisable.
Alternative: lubricants with other preservatives or freshly packaged products without long-shelf-life preservation.
4. Propylene Glycol in Sensitivity
What it is: a commonly used solvent and humectant, also in cosmetics and pharmaceuticals.
Risk: for the majority of people it's no problem. For a minority (estimated 1-3%) it causes local irritation, a burning sensation or an allergic reaction.
What to do: if you consistently experience irritation after a lubricant with propylene glycol on the label, try a variant without.
5. Fragrances, Dyes and Flavors
What they are: scent and flavor often come from synthetic compounds, dyes from pigments. All foreign to mucous membranes.
Risk: raised chance of irritation and allergic reaction. Scent on mucous membranes is usually worse than scent on skin anyway.
Alternative: unscented, colorless, flavorless lubricants for vaginal and anal use. Flavor/scent isn't a 'plus': it's a risk.
6. Spermicide Nonoxynol-9
What it is: an ingredient in some condoms and lubricants that immobilizes sperm cells.
Risk: research has shown that nonoxynol-9 can damage vaginal and anal mucous membranes with regular use, which actually raises the risk of STI transmission (including HIV) instead of lowering it.
Alternative: choose contraception and lubricant separately.
What to Look for on a Label
- Water-based as base (universally safe with condoms and toys)
- Low osmolality (ideally ≤380 mOsm/kg)
- Glycerin-free if you're prone to yeast infections
- Fragrance- and dye-free
- pH-friendly (around 4-4.5 for vaginal use, neutral for anal)
The AIA Natural Lubricant is designed with these guidelines in mind, suitable for sensitive mucous membranes.
Common Mistakes
Using saliva as lubricant. Unhygienic (mouth bacteria don't belong vaginally) and not effective for longer than a minute.
Using body lotion or cream. Contains fragrance, preservatives and oil: not safe for mucous membranes or condoms.
Using oil with latex condoms. Degrades latex, condom can tear. Read our blog on massage oil vs lubricant.
Assuming 'natural' on the label = safe. Always read the ingredient list.
FAQ
Is all silicone lubricant safe?
For mucous membranes and condoms yes. Not for silicone toys: they can be degraded by prolonged contact.
How long does lubricant last after opening?
Usually 12 months after opening. Check the open-jar icon (PAO symbol) on the label.
What if I like fragrance?
Use fragrance on skin (massage oil) and choose unscented for mucous membranes. Two different products for two different purposes.
Conclusion
Choosing good lubricant is a matter of reading labels and knowing the basic guidelines: water-based, low osmolality, glycerin-free if sensitive, and no fragrance or color. Unnecessary ingredients aren't just unnecessary: they can actively damage the mucous membranes you actually want to protect.
Choose deliberately: discover the AIA Natural Lubricant or browse the entire lubricant and oil collection.
Sources:
1. World Health Organization (2012). Use and procurement of additional lubricants for male and female condoms. WHO/RHR/12.33.
2. Wilkinson, E. M., et al. (2019). Lubricant use and microbial vaginosis risk: a systematic review.
3. Phillips, D. M., et al. (2002). Nonoxynol-9 and HIV transmission risk. AIDS Research and Human Retroviruses.
