Condoms are a crucial tool in protecting against sexually transmitted infections (STIs). However, even when people use them correctly, they do not provide 100% protection against all types of STIs.

Condoms, also known as barrier contraception, are widely available for preventing many STIs. They are thin, flexible pouches that a person can either wear over the penis or that people with vaginas can use internally. Condoms can prevent contact with bodily fluids, reducing a person’s STI risk.

STIs are infections that pass from one person to another through sexual contact. However, some transmit through skin-to-skin contact, meaning that they may still pass between people despite one or both of them wearing condoms.

As such, to help reduce the risk of transmission and support safe sex, people should use condoms correctly, choose the right condoms for them, store them correctly, and control STI risks in other ways.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

A selection of condoms-1.Share on Pinterest
Yaroslav Danylchenko/Stocksy

According to the World Health Organization (WHO), condoms are among the most effective methods of preventing most STIs when people use them correctly and consistently.

They can help prevent most STIs by stopping or reducing the exchange of bodily fluids. They can also provide a barrier that prevents some skin contact with secretions or sores. Condoms can provide protection against:

However, even when people use them correctly, condoms do not protect against all types of STIs. For example, condoms do not provide as much protection for STIs that cause extra-genital ulcers or lesions, such as genital herpes, genital warts, and syphilis.

Condoms help prevent the transmission of STIs and, with proper use, can also reduce the risk of unwanted pregnancies.

Different condoms protect against STIs to different extents. The level of STI protection varies depending on the material from which the manufacturers made the condom, where the user wears it, and which type of sex a person is having.

Advocacy group Planned Parenthood advises that the three different condom materials affect their level of STI protection in the following ways:

  • Latex condoms: As the most common type, these consist of rubber and can protect against pregnancy and STIs. However, oil-based lubricants can damage latex, so people should only use water- or silicone-based lubricants with latex condoms.
  • Non-latex condoms: These consist of plastics such as polyurethane, nitrile, or polyisoprene, and people often use them due to latex allergy. These can reduce the risk of STIs and pregnancy, and people can use any lube with them, except for polyisoprene condoms, which oil-based lubricants can also damage.
  • Animal skin condoms: Manufacturers use the linings of animal intestines, often those of sheep, to make these condoms. They do not protect against STIs but may reduce the risk of unplanned pregnancy. They are safe for those with latex allergy and can withstand any lubricant.

External and internal condoms also provide different levels of protection against STIs.

  • External condoms: A person wears an external condom over the outside of their penis. According to the United Kingdom’s National Health Service (NHS), wearing a condom during every sexual encounter is the most effective way to prevent STI transmission.
  • Internal condoms: These are wearable inside the vagina or anus during sex. They have an inner ring, and the user can push the condom in with their finger. The outer ring should stay outside the vagina or anus. These can reduce the risk of STIs during vaginal sex, but not enough data confirm their effectiveness during anal sex.

Condoms are the most effective method for reducing the risk of STI transmission. However, they are not 100% effective at preventing transmission, especially if a person does not use them correctly. According to an older review, condoms have the following levels of effectiveness for some of the most common STIs:

  • Gonorrhea: More than 90% protection
  • Chlamydia: 50% to 90% protection
  • Syphilis: 50% to 71% protection with correct use, 29% with typical use
  • HIV: More than 90% protection, approximately 85% with correct use
  • Hepatitis B virus: More than 90% protection
  • Herpes simplex virus type 2 (HSV-2), or genital herpes: 10% to 50% protection, approximately 40% reduction in transmission
  • Human papillomavirus (HPV): No significant protection

Condoms are less effective in preventing genital herpes and HPV, which can cause genital warts as they spread through skin-to-skin contact. If herpes sores or genital warts develop on parts of the genitals that a condom does not cover, these viruses may still transmit.

The risk of STI transmission increases if a condom breaks or a condom user has not put it on correctly and safely.

While not all condoms provide the same level of protection for every STI, a person can take steps to reduce the risk of transmission.

Planned Parenthood advises that the best way to make condoms effective is to use them correctly during every instance of vaginal, anal, or oral sex. This means the following:

  • keeping them rolled down the penis before any skin-to-skin contact occurs
  • only wearing one external condom at a time
  • not using an internal and external condom at the same time
  • checking the expiry date to confirm that the condom is still usable
  • storing condoms in a cool, dry place and avoiding exposure to direct sunlight or sharp objects
  • avoiding keeping condoms in a pocket, bathroom, or car for longer than a month to prevent moisture or heat damage
  • using a lubricant that will not damage the condom
  • carefully removing the condom after sex and keeping fluids away from sexual partners

Using condoms safely is the most effective way to reduce STI transmission aside from not having any vaginal, anal, or oral sex. However, other measures can help, including:

  • receiving vaccinations for HPV and hepatitis B, especially as condoms do not prevent HPV transmission
  • having fewer sex partners or practicing mutual monogamy with a partner who has tested negative for STIs
  • receiving regular tests for STIs and sharing all results with recent and current sexual partners

People can also explore options for individuals at higher risk of acquiring certain STIs. For example, to help prevent HIV, a person can use preexposure prophylaxis (PrEP). This is a prophylactic treatment containing antiviral medication, which can help lower the risk of acquiring HIV.

Sexually active people can reduce their exposure to health risks by being open with a healthcare professional. Clinical professionals can help individuals choose the most appropriate STI checks at the right time, especially as many STIs do not cause symptoms.

According to recommendations from the Centers for Disease Control and Prevention (CDC), the following table explains when certain groups could seek testing:

Age/Sex GroupRecommended Intervals for STI Testing
All sexually active people ages 13 to 64HIV: At least once yearly
Gonorrhea and chlamydia: Yearly
Females age 25 years and older with risk factors such as new partners, multiple partners, or a partner with a confirmed STITalk with a healthcare professional about throat and rectal testing options for the throat and rectum
Pregnant peopleSyphilis, HIV, hepatitis B, and hepatitis C: Starting early in pregnancy, with repeat testing possibly necessary
Pregnant people at riskThe standard pregnancy STI check as well as chlamydia and gonorrhea: Starting early in pregnancy, with repeat testing possibly necessary
Sexually active, gay males, bisexual males, or males who have sex with malesSyphilis, chlamydia, and gonorrhea: At least once a year or every 3 to 6 months if a person has multiple or anonymous partners
HIV: At least once a year, or every 3 to 6 months depending on risk factors
Hepatitis C: At least once yearly if living with HIV
Anyone who shares injection drug equipmentHIV: At least once yearly
People who have had oral or anal sexTalk with a healthcare professional about throat and rectal testing options for the throat and rectum

Confidential free or low cost testing clinics are available for people who do not feel comfortable discussing sexual health with their usual physician or medical professional.

A positive STI test result can cause concern. However, treatments are available for many common STIs, and some are completely curable.

Speak to any partners about positive STI results and discuss the next steps for preventing transmission and treating the infection with a clinician.

Some clinical departments can inform a partner that they experienced an STI exposure without naming the individual who received the test for those who do not feel comfortable discussing it with partners.

Wearing a condom is one of the most effective ways to prevent STI transmission. However, they do not protect against all types of STIs.

Condoms provide less protection for STIs that pass from one person to another through skin-to-skin contact, such as HPV and genital herpes. Not all types of condoms are equally effective at preventing STI transmission.

Using condoms correctly and consistently is among the best methods for preventing STI transmission. It is also advisable to store them correctly and avoid lubricants that may damage the condom.

Wearing a condom does not remove the need for regular STI testing in sexually active people, as this can help to identify and treat STIs they may still have acquired.