County of Marin Health and Human Services

Pre-Exposure Prophylaxis (PrEP)

What is PrEP?

Pre-Exposure Prophylaxis or "PrEP" is a pill for people who are HIV negative that protects you from HIV.

Read PrEP Basics in English and Spanish.

Read the CDC overview PrEP basics for more information.

Is PrEP safe and effective?

PrEP should be taken every day to be effective. Several studies show that people who took PrEP consistently had up to a 99% lower risk of getting HIV infection than those who did not take PrEP.

Should I take PrEP?

PrEP is not for everyone. Potential candidates include anyone who:

  • Is in an ongoing sexual relationship with a person living with HIV who is not virally suppressed 
  • Does not use condoms regularly when having sex with partners at known risk for HIV
  • Is a gay or bisexual man who has had sex without a condom or diagnosed with a sexually transmitted infection within the past six months
  • Has injected drugs and shared needles within the past six months 

Marin PrEP Providers:

PrEP is covered by most insurance plans, including Medi-Cal. If you need help covering co-pays or do not have insurance, there are assistance programs that can help. Visit Color for assistance with accessing PrEP or PEP. 

Color is contracted with CDPH to offer PrEP and PEP in California through the PrEP-Assistance Program (PrEP-AP). Their patient support team is available 8am-5pm every day. Call 1-833-919-3696 or email

Post Exposure Prophylaxis (PEP)

PEP stands for post-exposure prophylaxis. It involves taking a pill to prevent HIV as soon as possible but no more than 72 hours (3 days) after you may have been exposed to HIV, to try to reduce the chance of becoming HIV-positive.  The sooner a PEP regimen is started postexposure, the greater the chances that it will prevent HIV infection. 

Sources: (including images); Centers for Disease Control and Prevention (CDC)