“Safer sex” is a term that can mean many things:

  • Avoiding bodily fluid exchange
  • Using prophylactics (such as condoms)
  • Using HIV medications to prevent transmission of the virus
  • Limiting the number of sexual partners
  • Curtailing alcohol and drug use (which can impair judgment).

In fact, safer sex often involves a combination of these approaches.

The only way to know for sure whether you are HIV positive, even after an activity that is considered to be very low risk for HIV transmission, is to get tested. If you’ve contracted another sexually transmitted infection, it’s also a good idea to be tested for HIV.

External Condoms (also known as male condoms)
Several studies have demonstrated that external condoms made of either latex or polyurethane are effective barriers against HIV. They cover the penis and provide an effective barrier to exposure to secretions, such as semen and vaginal fluids, thereby blocking the sexual transmission of HIV. 

Similar studies have also demonstrated that these types of condoms also prevent other common sexually transmitted viral infections, such as herpes simplex virus (HSV) and hepatitis B virus (HBV). 

Polyurethane condoms are an effective alternative to latex condoms, especially for people with an allergy to latex. 

Condoms made of natural materials—such as lambskin—are not a consistently effective barrier against many viruses. In one laboratory study, HIV was found to pass through microscopic holes in lambskin condoms. Studies involving HSV and HBV reported similar results.

Internal Condoms (also known as female condoms)

The internal condom is a polyurethane pouch with flexible polyurethane rings at each end. It is inserted deep in the vagina or anus. The ring at the closed end holds the pouch in the vagina or anus. The ring at the open end remains outside the vagina or anus. When inserted properly, it helps to prevent pregnancy along with HIV and other sexually transmitted infections.

The key to effective protection is consistent and correct use of condoms. Incorrect use of condoms can increase the risk of slippage or breakage, which diminishes their ability to protect against the virus. Inconsistent use—for example, failure to use condoms with every act of vaginal or anal intercourse—can lead to HIV transmission.

Only water-based and silicone-based lubricants should be used with latex condoms. Never use oil-based lubricants, including hand or body lotion, baby oil, vegetable oil or shortening, massage oil, mineral oil or petroleum jelly (e.g., Vaseline). Oil-based lubricants can damage latex and cause latex condoms to tear more easily.

Some pre-lubricated condoms and separately sold lubricants contain a chemical called nonoxynol-9. While nonoxynol-9 has been shown to kill sperm (and potentially reduce the risk of pregnancy) and various sexually transmitted infections, some men and women are allergic to this chemical. This can cause irritation inside the vagina and anus, which can increase the risk of HIV transmission if the condom breaks.

Antiretroviral (ARV) Therapy
HIV medications can also be used to prevent sexual transmission of the virus. Pre-exposure prophylaxis (PrEP) is an HIV prevention tool in which an HIV-negative person takes antiretroviral medication to reduce the risk of contracting HIV. Post-exposure prophylaxis (PEP) involves taking a short course of ARV drugs, usually for a month, to prevent HIV transmission after a high-risk exposure. Treatment as prevention (TasP) refers to taking antiretoivrals to prevent sexual tranmission. People living with HIV who maintain an undetectable viral load have effectively no risk of transmitting the virus via sex, a concept known as Undetectable Equals Untransmittable, or U=U. 

Last Reviewed: January 5, 2023