Two people in underwear hugging inside of a condom.

Illustration by Marta Pucci


Safer sex 101

by Jen Bell, Former Writer at Clue; and Nicole Telfer, Science Content Producer
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What is “safer sex”? Having sex means having the risk of getting a sexually transmitted infection (STI), but there are many ways to reduce that risk. Everyone has the right to decide what they want to do with their body, including which protection to use. Read on to get informed so you can make the best decisions for you.

“Safer sex” means you have a highly reduced risk of STI transmission, but it’s impossible to have sex and be 100% protected. This is why what used to be called “safe sex” in the 1980s got changed to “safer sex” in the 1990s.

How to have safer sex

Safer sex is a way to reduce the risks of STIs, while still having sex.

If you want to reduce your risks of catching or passing on an STI as much as possible, you need to do all three of these safer sex components:

  1. Correct, consistent (always, not just some of the time) use of barriers (condoms and other barriers, like dental dams) on body parts or toys for any kind of vaginal, anal or oral sex
  2. Being mutually sexually exclusive: that is, both you and your partner only have sex with each other
  3. Regular testing for all STIs, by you and your partner(s)

What does this mean for different sexual activities?

Different types of sexual activities can put you at risk for different STIs.

STIs can be transferred through more than just semen, but also through vaginal fluids, direct mucous membrane (skin) contact, blood, saliva, and even feces (1). It is hard to establish which sex act is responsible for disease transmission, since people often engage in more than one type of sexual activity (e.g. having both oral sex and penis-in-vagina sex during the same session).

But as a general guideline, this list can help you figure out which STIs you might be at risk for during different sexual activities (2,3).

  • Kissing: oral herpes (HSV-1)
  • Oral sex: Chlamydia, gonorrhea, HPV, herpes (HSV-1 and HSV-2), syphilis, HIV, trichomoniasis
  • Fingering and fisting (anal and vaginal): Anything that can cause cuts or tears to the anus or genitals (like fingernails, rings, or tearing of the mucous membranes) can increase possible transmission of any blood-borne STIs (like HIV or hepatitis B or C). If your fingers contact other people’s genitals and then your own, STIs can be passed through genital secretions. To be safe, always wash your hands after touching someone else's genitals, or even wear gloves to be extra safe.
  • Penis-in-vagina sex: HIV, gonorrhea, chlamydia, herpes, HPV, syphilis, chancroid, hepatitis B & C, trichomoniasis, genital warts
  • Anal sex: HIV, hepatitis B & C, HPV, syphilis, gonorrhea, chlamydia, herpes, genital warts, diseases transmitted through microorganisms from feces (Giardia, Shigella, Salmonella, Campylobacter, and E. coli) (4)
  • Sex toys: Not much research has been dedicated to STI transmission via sex toys. It is possible that STIs transmission can occur from genital fluids on the sex toy. To be safe when sharing toys, use a condom or clean and sterilize them. Always put on a new condom or clean the toy again when changing from one person to another, or from anal to vaginal use.
  • Vulva-to-vulva sex (scissoring): HPV, HSV-1, HSV-2, syphilis, chancroid, chlamydia, gonorrhea, genital warts, HIV

Prevention: Vaccines for HPV and hepatitis B

Human papillomavirus (HPV), the most common STI in the United States, can have long-term consequences, like genital warts and cancers of the cervix, penis, and throat (5,6). But HPV is preventable through vaccination, if given before coming in contact with the virus. Routine vaccinations are offered to children of all genders around ages 11 and 12, and booster shots are available for young adults and people who are at high risk of HPV contraction (7). If you’ve already had sex, you can still get the vaccination, which will give you protection from other HPV types covered in the vaccine (7).

Vaccinations are also available for hepatitis B, which is a viral disease spread through blood, mucous membrane contact, and sexual fluids. In the United States, this vaccination schedule is given during infancy, which provides protection from hepatitis B for at least 30 years (8). Booster vaccinations are also available for people who are at risk of contracting hepatitis B.

Prevention: Barrier methods

How effective are condoms against various STIs?

Barrier methods like external condoms, internal condoms, gloves, or dental dams are great choices to use during any type of sexual activity.

They do what they say they will—they create a barrier between your genitals/mouth/anus and your partner’s genitals/mouth/anus. These types of barriers will reduce the risk of STI transmission during sex, but not fully eliminate the risk altogether. The best way to be protected to is always consistently and correctly use a barrier method during every sex act (2).

External (male) condoms are a cheap, readily available (in many countries), and easy to use barrier method if you are having vaginal/oral/anal sex with a person with a penis. If you are having sex with a partner and are using sex toys (like vibrators, dildos, or anal inserts), an external condom should also be used over the sex toy to prevent the transmission of STIs between partners (2).

Latex external condoms are recommended for preventing STIs, as these are the most commonly available and researched. If you or your partner have an allergy to latex, try using polyurethane condoms instead, though these may break and slip off more easily (9,10). Little research has been done to test if condoms made from other synthetic materials, like polyurethane, actually prevent STIs as well as latex. The general consensus is that they do provide STI protection. More research is needed here. Natural membrane (lambskin) condoms do not provide STI protection and should not be used with a partner of unknown STI status (11).

However, condoms cannot offer 100% protection from all STIs, since some STIs are spread by skin to skin contact (like HPV or herpes), and the infected skin may not be covered by the condom.

It is difficult to establish how effective condoms are, as it would be unethical to perform a controlled trial and only provide half of a population with condoms, thereby putting the other population at great risk. For this reason, researchers look to studies of real populations, where answers of sexual health practices can be reported and rates of disease/STI development can be monitored.

HIV is the most studied STI in relation to condom efficacy, and has been suggested to prevent HIV transmission for penis-in-vagina sex by approximated 80 to 95% (12-14). Although less studied, consistent and correct condom use is also effective in reducing the spread of other STIs that are spread through genital secretions, like chlamydia, gonorrhea, and trichomoniasis (2). STIs that are spread through direct skin-to-skin contact, like genital herpes or genital ulcer diseases may not offer as much protection as a condom, as if the infected skin is exposed, then the condom can only offer limited protection (2).

What about dams and gloves?

During oral sex on the vulva (cunnilingus) or anus (anilingus), infections—including HIV, syphilis, herpes, gonorrhea, HPV, trichomoniasis, and chlamydia—can be passed from mouth to genitals, or vice versa (15). To protect yourself use a dam, or a condom cut lengthwise to cover the vulva and/or anus.

If you’re touching your partner’s genitals, or they are touching yours, then there is a risk of transmitting some STIs (such as HPV, genital warts, chlamydia, herpes simplex virus (HSV) 1 and/or 2, syphilis). Infection risks increase when more fingers or a whole hand are inside the vagina or anus (sometimes called fisting), as this can cause small tears or trauma, which can increase STI transmission (16). To prevent STI transmission, latex or nitrile gloves can be used.

Can my partner and I stop using condoms after awhile?

If you want to stop using condoms and other barriers, precautions need to be taken. Try using barriers and being exclusive for an extended period of time, and then get tested for STIs. If all of your tests come back negative and you both agree to remain exclusive, you can consider stopping using condoms (and other barrier methods).

Having an extended time period where both partners are exclusive and use barrier methods allows time for any STIs acquired before you two got together to show up on tests, and also gives you both some time to establish trust and see if exclusivity is something each of you wants to continue. One problem here is that not everyone will be honest with partners about sex outside the relationship.

What if we’re not exclusive?

If there's any one part of safer sex that doesn't work with your relationship, you can either change that situation, or adjust what you do to work better for you. For example, if you know you and a partner aren't being exclusive, or are not using barriers all the time, you can get tested more often than you would otherwise, or leave the relationship.

Important things to remember

Even though in the moment, going without condoms and other barriers might feel better or less socially awkward, in the long term, STIs can seriously affect your health. So if things are moving quickly, try to press pause and take a few moments to be sure the choices you're making are the ones you really want.

If you don't practice safer sex, remember that you are not magically immune. If any of us are having sex with another person, there’s a risk of getting an STI. If you're not using barriers, you have to understand that you don't have the same level of protection that people who are using barriers do.

Is it possible to have 100% risk-free sex?

The only 100% safe sex when it comes to sexually transmitted infections is sex where there is no possibility of body fluids being exchanged, and no direct contact between mucous membranes (the soft skin at the opening of your genitals, mouth, or eyes).

If you want to have absolutely no risk of acquiring a sexually transmitted infection, then you need to avoid any kinds of intimate contact where body fluids of any kind are exchanged. This means no direct oral, genital, or anal contact. Kissing does pose an oral herpes risk.

There are lots of ways you can be sexual and stay safe. Solo masturbation, dry-humping (rubbing genitals with clothes on), sexy talk, massage (without touching genitals) and cuddling are some of the things that you can do that won’t spread STIs.

What if my partner doesn’t want to get tested?

Whether it's a casual or serious relationship, it’s important to discuss your sexual health history with your partner, and ask them about theirs. This gives both of you the chance to make an informed decision about what types of sex you want to have and what safer sex precautions you want to take. Your partner might lie about their STI status, or refuse to get tested, but at least you asked. Their reaction to discussing this subject will help you get to know them better. If they are really against getting tested, and talking about safer sex, this might affect your decision about having sex with them.

Safer sex is the best option if you want to have sex and also be protected against STIs, but it's up to each of us to decide what we want, and what level of risk we and our partners are comfortable with.

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