Condoms: latex, latex-free and getting the size right

A condom that fits properly is both safer and considerably better. Most complaints — "too tight", "it slips", "it does not feel like anything" — are size complaints rather than material ones.

Materials

• Latex — the default. Cheap, thin, very stretchy, protects against pregnancy and STIs. Not suitable if you have a latex allergy.
• Polyisoprene — feels and stretches like latex, but without the proteins that trigger latex allergies.
• Polyurethane — thin, conducts heat well, suitable for people with latex allergies.
• Lambskin / natural membrane — a barrier against pregnancy only. It does not reliably block STIs, so it is not a replacement for latex in casual use.

Sizing

Condoms are sized by nominal width — the flat width of the condom in millimetres, not the length. Measure the erect girth with a tape (or a strip of paper you then measure against a ruler) and divide by two for a rough nominal width. Most standard condoms sit around 52–56 mm; larger girths need 57 mm and up, smaller girths are better with 49–51 mm. Length is much less important, since condoms unroll only as far as needed.

Lubricant compatibility

Use water-based or silicone-based lubricant with latex and polyisoprene condoms. Oil-based products — including many massage oils, body butters and petroleum jelly — weaken latex and cause breaks. If you want oil, choose a polyurethane condom.

Using and storing them

1. Check the expiry date and the air bubble in the wrapper before opening.
2. Open with fingers, never teeth or nails.
3. Pinch the tip to remove air, then roll down.
4. One condom, one use. Never use two at once.
5. Store away from heat, sunlight and wallets — friction and warmth degrade latex over time.

Changing between types is fine, but changing between partners within one act always requires a new condom.