Safer sex basics: condoms, dental dams, vaccines and testing
Quick answer
Safer sex means combining a few simple habits that lower the chance of passing on or catching a sexually transmitted infection (STI): using a condom or dental dam correctly every time, choosing a lubricant that will not damage it, getting vaccinated against HPV and hepatitis B, and testing regularly. No single method removes all risk, but together they protect you well.
Key points
- Used correctly every time, condoms greatly reduce the risk of HIV and many other STIs.
- Oil-based products such as body lotion or petroleum jelly can damage latex condoms; water-based or silicone-based lubricants are safe with them.
- Dental dams are thin barriers that reduce STI risk during oral sex.
- Vaccines protect against HPV and hepatitis B, two common sexually transmitted viruses.
- Condoms cannot fully protect against infections spread by skin contact, such as herpes and HPV, so regular testing still matters.
What does safer sex actually mean?
Safer sex is any step that lowers the chance of an STI passing between partners. It is not about the number of partners or any judgement of your choices: anyone who is sexually active can catch an STI, and anyone can take simple steps to reduce the risk.
The most effective approach combines several layers: a physical barrier such as a condom, vaccination where it is available, regular testing for you and your partners, and honest conversations about sexual health. For HIV specifically, medicines called PrEP and PEP add further protection.
How do you use external and internal condoms correctly?
External condoms are worn over the penis and are usually made of latex. Polyurethane or polyisoprene versions are available for people with a latex allergy. Internal condoms are placed inside the vagina or anus and are usually made of nitrile or polyurethane. Both work by stopping body fluids passing between partners.
Most condom failures come from how a condom is used rather than from the condom itself. A few habits make a large difference.
- Check the expiry date and look for a recognised safety mark, such as the CE or UKCA mark in the UK, or certification by your national standards body.
- Open the packet carefully with your fingers, not your teeth or scissors, to avoid tearing it.
- Put the condom on before any genital contact, not part-way through.
- Use a new condom every time and for each type of sex, and never reuse one.
- Do not use two condoms at once, including an external and an internal condom together, as friction can make them tear.
- Store condoms somewhere cool and dry, away from sharp objects and direct heat.
Which lubricants are safe to use with condoms?
Lubricant can make sex more comfortable and lowers the chance of a condom tearing. The type matters. Oil-based products, such as massage oil, body lotion, petroleum jelly and baby oil, weaken latex and polyisoprene condoms and can cause them to split. Water-based and silicone-based lubricants are safe to use with all condoms.
Internal condoms made of nitrile or polyurethane are not damaged by oil, but always check the instructions on the packet. Some vaginal medicines, such as certain thrush creams and pessaries, can also weaken latex, so ask a pharmacist if you are using one.
Health bodies advise against relying on condoms or lubricants that contain the spermicide nonoxynol-9 for STI protection, because frequent use can irritate delicate skin and may increase the risk of HIV.
What is a dental dam and when is it used?
A dental dam is a thin, square sheet of latex or polyurethane placed over the genitals or anus during oral sex. It acts as a barrier that reduces the spread of infections such as gonorrhoea, syphilis, herpes and HPV between the mouth and the genital area.
Use a new dam each time, keep the same side facing the body, and use only water-based or silicone-based lubricant with latex dams. Dental dams can be harder to find than condoms; sexual health clinics often provide them free, and an external condom cut lengthways along one side can be used as an alternative.
Which vaccines help protect your sexual health?
The HPV vaccine protects against the types of human papillomavirus that cause most cervical cancers and genital warts, as well as some cancers of the throat, anus and penis. It works best when given before a person becomes sexually active, which is why many countries, including the UK and India, offer it to adolescents. Adults may also benefit, so ask a clinician whether it is recommended for you.
The hepatitis B vaccine protects against a virus that can be passed on through sex and blood and can damage the liver. Many countries now vaccinate all babies, and adults at higher risk who were not vaccinated can usually get it from a doctor or sexual health clinic. Some services also offer hepatitis A and other vaccines to people at higher risk.
What can condoms not protect against?
Condoms are very effective against infections passed on through body fluids, such as HIV, chlamydia and gonorrhoea. They give less protection against infections spread by skin-to-skin contact, such as herpes, HPV and syphilis, because these can affect skin that a condom does not cover. They still lower the risk, so they remain well worth using.
Because of these limits, regular STI testing is part of safer sex even for people who always use condoms. It is also a good idea to avoid sexual contact while you or a partner has visible sores, blisters or warts, and to get them checked by a clinician.
When to see a doctor
- Seek urgent advice within 72 hours if a condom broke or slipped and there is a chance of HIV exposure, to ask about PEP.
- Ask about emergency contraception as soon as possible if a condom failed and pregnancy is possible.
- Book an STI test if you notice unusual discharge, pain when urinating, genital sores, blisters, warts or a rash.
- See a clinician if you have itching, swelling or a rash after using condoms, as this could be a latex allergy.
Frequently asked questions
Can I use oil-based lubricant with condoms?
Not with latex or polyisoprene condoms. Oil-based products such as petroleum jelly, body lotion and massage oil weaken these materials and can make the condom break. Choose a water-based or silicone-based lubricant instead. Internal condoms made of nitrile or polyurethane are not damaged by oil, but always check the packet instructions first.
Do condoms protect against herpes and HPV?
They lower the risk but cannot remove it. Herpes and HPV spread through skin-to-skin contact, and they can affect areas that a condom does not cover. Using condoms consistently still reduces transmission. The HPV vaccine adds strong protection against the most harmful HPV types, and regular check-ups help catch any infection early.
What should I do if a condom breaks?
Stay calm and act quickly. If pregnancy is possible, ask a pharmacist or clinic about emergency contraception as soon as you can. If there is any chance of HIV exposure, contact a sexual health clinic or emergency department about PEP within 72 hours, ideally within 24. Book an STI test for about two weeks later, or sooner if symptoms appear.
Is the HPV vaccine only for young people?
It works best when given before someone becomes sexually active, so programmes focus on adolescents. However, many adults can still benefit, and some health services offer it to adults at higher risk, such as men who have sex with men. Eligibility differs between countries, so ask a doctor or sexual health clinic whether it is recommended for you.