Can you pass on or catch an STI without ejaculation?

Yes. Infections can be passed on even if the penis doesn’t fully enter the vagina or anus, and even if nobody ejaculates (comes). This is because:

• pre-cum (pre-ejaculate), vaginal fluid and anal fluids can all carry infections
• some STIs spread when your genitals touch another person’s genitals
• some STIs spread through any skin-to-skin contact of the genital area

Even putting the tip of the penis in for a moment, sometimes called dipping, carries a risk for both partners.

Infections carried in body fluids

Chlamydia and Gonorrhoea are spread through vaginal fluid and semen, and can also be in pre-cum. You can catch them through vaginal, oral or anal sex without a condom, and from fluid that gets onto sex toys or hands.

Trichomonas is passed on through vaginal sex, skin-to-skin contact of the genital area and sharing sex toys.

HIV can be passed on through blood, semen, pre-cum, vaginal fluid and anal fluids. Hepatitis B spreads when blood, semen or certain other body fluids get into the body, even in tiny amounts.

Infections spread by skin contact

Some STIs don’t need any body fluid at all:

• Herpes spreads through skin contact with the infected area, even when there are no sores.
• HPV, including the types that cause genital warts, spreads through skin-to-skin contact of the genital area.
• Syphilis spreads through contact with a Syphilis sore on the genitals, bottom or mouth.
• Molluscum contagiosum, pubic lice and scabies spread through close skin or body contact.

Condoms only protect the skin they cover, so they can’t fully protect you from these infections, and they won’t stop pubic lice or scabies. Read more in “3 STIs you can catch even if you use a condom”

For HIV, there is some evidence that ejaculation raises the risk. In a study of gay men in Sydney, the chance of catching HIV from receptive anal sex with a partner who had HIV was about 1.4% each time when he ejaculated inside, and about 0.65% when he pulled out. These are rough estimates from one study. Pulling out lowered the risk, but didn’t remove it. The study was done before PrEP was available, and before it was known that people on effective treatment can’t pass HIV on. The US Centers for Disease Control and Prevention (CDC) also says ejaculation in the mouth may add to the risk of HIV during oral sex when someone has mouth ulcers, bleeding gums or genital sores, although it notes there are no studies measuring this.

Someone with HIV who is on effective treatment and has an undetectable viral load can’t pass HIV on, whether or not they ejaculate.

There is little research on whether ejaculation changes the risk of Hepatitis B or other STIs. For oral sex, the CDC says no studies have shown whether contact with pre-cum or cum makes STIs more likely to pass on. Because pre-cum, vaginal fluid and skin contact can all pass them on, it’s safest to assume that sex without ejaculation still carries a risk.

No. Pulling out, or withdrawing the penis before ejaculation, doesn’t protect you from STIs, because pre-cum and skin contact can still pass on infections.

It isn’t a reliable way to avoid pregnancy either. Pre-cum can contain sperm from a recent ejaculation, and it is easy to pull out too late. Use a condom from the start, before there is any contact between the penis and your partner’s genitals.

If you have had sex without a condom or other contraception, emergency contraception can help prevent pregnancy. A copper coil (IUD) can be fitted up to 5 days after sex, and the emergency pill must be taken within 3 or 5 days, depending on the type. The pill works better the sooner you take it, and you can get it from most pharmacies.

Each time you have sex without protection with someone who has an STI, there is another chance of catching it, so the risk builds up over time. But it doesn’t simply multiply. Having sex 20 times doesn’t mean you are exactly 20 times as likely to catch an infection.

This is because:

• you can catch an infection the first time you have sex with someone who has it, and once you have caught it, more sex doesn’t add to your chance of catching it
• there is only a risk if your partner actually has an infection
• the risk each time depends on the infection, the type of sex, and whether you use condoms, PrEP or treatment

The simplest way to lower your risk is to use condoms every time and test regularly if you have new or casual partners.

You can catch or pass on STIs through oral sex even if nobody comes. These include Chlamydia, Gonorrhoea, Syphilis, Herpes and HPV. HIV can also pass on through oral sex, but the risk is much lower than for anal or vaginal sex. Oral sex that involves the anus (rimming) can also pass on Hepatitis A and B.

Using a condom for oral sex on a penis, or a dental dam for oral sex on a vagina or anus, lowers the risk. Read more in “I had unprotected oral sex. Should I get tested?”

You can lower your risk of catching or passing on an STI by:

• using a condom from the start of vaginal, anal and oral sex, and a dental dam for oral sex on a vagina or anus
• not sharing sex toys, or washing them and covering them with a new condom before anyone else uses them
• getting vaccinated against HPV and Hepatitis B, and in England the MenB vaccine, which gives some protection against Gonorrhoea, if you are eligible
• taking PrEP if you are at higher risk of HIV
• getting tested at least once a year if you have sex without condoms with new or casual partners, and before you stop using condoms with a new partner

Read more in “7 ways you can catch an STI without having sex”

If you have symptoms, such as unusual discharge, pain when peeing, or sores, blisters or lumps around your genitals, mouth or anus, get tested straight away. If you don’t have symptoms, some infections need time to show up on a test:

• Chlamydia and Gonorrhoea: from about 2 weeks after sex.
• HIV: UK guidance says a fourth-generation lab blood test is reliable from 45 days after sex, and a rapid finger-prick test that gives an instant result from 90 days.
• Syphilis: a test in the first 3 months can miss it, so you may need a repeat test.

If you think you have been exposed to HIV, get urgent medical care straight away and ask about PEP (post-exposure prophylaxis), a medicine that can stop you getting HIV. It has to be started within 72 hours, and the sooner you start it, the better.

Better2Know offers:

• Platinum Screen: our most comprehensive STI screen. It tests for 12 infections, including Chlamydia, Gonorrhoea, Herpes 1, Herpes 2, HIV, Syphilis and Trichomonas, from 28 days after possible exposure, with results in 3 days. You can book it at one of our clinics or order a Platinum Screen home test.
• Oral Screen home test: if you have had oral sex. It checks your throat and genitals for Chlamydia and Gonorrhoea, and tests your blood for Syphilis, Herpes 1 and Herpes 2, from 14 days (28 days for Herpes).
• Blemish Screen: if you have a sore, blister or lump on or around your genitals, it tests a swab for Herpes 1, Herpes 2, HPV and Syphilis.

If you test before the window periods above, you may need a repeat test for HIV or Syphilis later. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Can you get an STI from pre-cum?

Yes. Pre-cum can carry HIV and other STIs, such as Chlamydia and Gonorrhoea, so you can catch an infection even if nobody comes.

Can you get an STI from dipping?

Yes. Putting the tip of the penis into the vagina or anus, even briefly, carries a risk of STIs for both partners, because of pre-cum, vaginal fluid and skin contact.

Can you get pregnant from pre-cum?

It’s possible. Pre-cum can contain sperm from a recent ejaculation, which is why pulling out isn’t a reliable way to avoid pregnancy.

You don’t need to ejaculate to pass on or catch an STI. Pre-cum, vaginal fluid and skin contact can all spread infections, so pulling out won’t protect you. Using a condom from the start and testing regularly are the best ways to protect yourself and your partners.

If you’re worried about an STI, get tested. Book a Platinum Screen at a clinic near you or order a home test kit. Our Patient Care Team is available 24/7 on 020 7099 0955.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 7 July 2023 and was last updated on 30 September 2026.

Medical review. This article was medically reviewed by Dr Steve Chapman, Doctor with a wealth of clinical experience in the field of STIs, on 29 August 2025. It is general information and not a substitute for personal medical advice.

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