PrEP can help reduce your risk of contracting HIV through sexual contact or injection drug use. PrEP may be taken as a daily pill or administered as a bimonthly injection.

According to HIV.gov, approximately 1.2 million U.S. people ages 13 years and older have HIV. Of this group, about 13% are not aware that they have it.

PrEP can help reduce the risk of transmission between serodiscordant (mixed-status) partners. If you don’t have HIV but are at an increased risk of infection, talk with a healthcare professional about whether PrEP is right for you.

Pills used for PrEP belong to a class of antiviral medications called nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs).

NRTIs block the reverse transcriptase enzyme HIV uses to convert its RNA into DNA (reverse transcription). This stops the virus from multiplying in your body.

Injections for PrEP are an antiretroviral called integrase strand inhibitors (INSTIs).

INSTIs block the enzyme integrase, another protein HIV uses for reverse transcription. Like NRTIs, INSTIs prevent the virus from replicating in the body.

Before starting PrEP, and at least once every 2 to 3 months while you’re taking the medication, you need to be tested for HIV and have a negative test result.

If you’ve been exposed to HIV or have symptoms of an acute infection, you need to wait to make sure you test negative before restarting PrEP.

PrEP cannot effectively treat HIV on its own, and drug resistance may develop if PrEP is taken during an active HIV infection.

There are three approved PrEP medications.

Truvada

Truvada is a tablet taken once daily. It contains the active ingredients emtricitabine and tenofovir disoproxil fumarate. It’s available in both brand-name and generic forms.

Truvada has multiple strengths, and the dosage can vary from person to person. It can help reduce the risk of HIV infection through sexual contact or injection drug use.

It can be used by adults and adolescents who weigh at least 35 kilograms (around 77 pounds). Truvada is approved for people with male or female anatomy.

Descovy

Descovy is also a tablet that’s taken once daily. It contains the ingredients emtricitabine and tenofovir alafenamide. It’s only available as a brand-name medication.

Descovy comes in multiple strengths, and the dosage can vary from person to person. It can help reduce the risk of HIV infection through sexual contact.

It can be used by adults and adolescents who weigh at least 35 kilograms (77 pounds). Descovy is only approved for people with male anatomy.

Apretude

The Food and Drug Administration (FDA) approved the injectable medication Apretude at the end of 2021. It contains the ingredient cabotegravir and is only available as a brand-name drug.

For the first 2 months, Apretude must be injected by a healthcare professional once a month. After the first two doses, it must be injected once every 2 months to be effective.

Apretude can only be used to reduce the risk of HIV infection through sexual contact. It can be used by adults and adolescents who weigh at least 35 kilograms (77 pounds). It’s approved for people with male or female anatomy.

You may benefit from PrEP therapy if you:

  • have a sexual partner who’s at risk of HIV or is HIV-positive
  • do not know a partner’s HIV status
  • have multiple sexual partners
  • have sex without condoms or other barrier methods
  • use intravenous drugs

You may not be eligible for PrEP if you:

  • have had an allergic reaction to the medication’s ingredients
  • have severe liver or kidney problems
  • have hepatitis

If you think you may have a higher chance of developing HIV, it’s important to discuss this and the steps you can take for protection from HIV with a trained healthcare professional.

If you don’t have health insurance, you may be able to access free or lower cost PrEP, HIV testing, and other preventive services at your local health department or community clinic.

PrEP is highly effective at preventing HIV when it’s used as directed by a healthcare professional.

According to the Centers for Disease Control and Prevention (CDC), PrEP pills and injections can decrease your risk of contracting HIV through sexual contact by around 99%. PrEP pills can decrease the risk of contracting HIV by around 74% in people who inject drugs.

It’s important to remember that PrEP pills aren’t effective right away. You need to take them daily for:

  • at least 7 days for maximum protection during receptive anal sex
  • at least 21 days for maximum protection during receptive vaginal sex
  • at least 21 days for maximum protection during injection drug use

It’s unclear how long PrEP injections take to reach maximum protection.

Common side effects include:

Rare but serious side effects include:

These are not all of the possible side effects of Truvada, Descovy, and Apretude.

Ask a healthcare professional or pharmacist for more information about these medications, including interactions with other prescribed or over-the-counter medications you take.

If you experience an allergic reaction or other serious side effects from PrEP medications, call 911 or local emergency services, or go to an emergency medical center right away.

What does PrEP do to your body?

PrEP interferes with HIV’s ability to reproduce itself, reducing the chances of HIV establishing itself in your system if you are exposed to it.

Is PrEP safer than condoms?

Although PrEP and condoms are both used to promote safer sex, the way they work and the benefits they provide are different.

Condoms provide a physical barrier that can reduce the risk of many sexually transmitted infections (STIs), not just HIV. Condoms can also reduce the risk of unintended pregnancy.

The materials used to create condoms are generally well tolerated, although some people may have latex allergies or sensitivities.

PrEP only protects against HIV. PrEP does not protect against other STIs or prevent pregnancy. PrEP, as with any drug, can cause side effects.

How long do you take PrEP pills?

Many people take PrEP pills indefinitely to provide long-term protection against HIV.

Some people take PrEP pills during periods when they anticipate a higher risk of HIV exposure, such as when engaging in certain sexual activities or during periods of increased HIV prevalence in their community.

This approach, sometimes called intermittent or on-demand PrEP, involves taking PrEP pills before and after potential exposure to HIV.

How much does PrEP cost?

PrEP costs depend on your location, insurance coverage, and whether generic versions of the medication are available.

Many insurance plans, including Medicaid and most private insurers, cover PrEP at no or low out-of-pocket cost to you.

Gilead, the manufacturer of Truvada and Descovy, offers a medication assistance program. The Apretude Savings Program may help you save on the cost of PrEP injections.

If you think you may be at risk of contracting HIV, it’s important to get regular testing and talk with a qualified healthcare professional about prevention steps you can take.

Part of your prevention strategy may involve taking PrEP. PrEP is a highly effective medication regimen that can reduce your risk of contracting HIV and transmitting the virus to your sexual partners.


Tess Catlett is a sex and relationships editor at Healthline, covering all things sticky, scary, and sweet. Find her unpacking her inherited trauma and crying over Harry Styles on Twitter.