• Complementary and Alternative Medicine

What is PrEP? A Simple Guide to HIV Prevention

Published: March 21, 2025
Updated: March 21, 2025
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PrEP – or pre-exposure prophylaxis – is an effective tool in the fight against HIV. It’s a medication that people who are at risk for HIV can take to lower their chances of getting the virus. When taken as prescribed, PrEP can reduce the risk of HIV from sex by about 99% and from injection drug use by at least 74%.

While you may have heard of PrEP, you may not know how it works or whether it’s right for you. It’s not just for one specific group of people. PrEP is for anyone who wants extra protection against HIV, whether they’re in a relationship with an HIV-positive partner, have multiple partners, or simply want peace of mind. 

The most common PrEP medications are Truvada and Descovy, both of which are taken as a once-daily pill. There’s also a long-acting injectable option for those who don’t want to take a daily pill. These medications work by blocking HIV from replicating in the body, so if you’re exposed to the virus, its chances of taking hold are decreased.

Access to PrEP has expanded in recent years, with more clinics, online services, and even financial assistance programs making it easier than ever to get. If you’re curious about whether PrEP is a good option for you, talking to a healthcare provider is a great first step. HIV prevention has come a long way, and PrEP is just one more way to take control of your sexual health with confidence. 

How Does PrEP Work?

PrEp acts as a protective shield, stopping HIV before it has a chance to take hold in the body. When taken correctly, PrEP medications build up in your bloodstream and create a barrier that blocks the virus from replicating. If you’re exposed to HIV – whether through sex or injection drug use – PrEP prevents the virus from making copies of itself, which means it can’t establish an infection.

PrEP is incredibly effective when taken as prescribed:

• For sexual transmission: PrEP reduces the risk of getting HIV by about 99%. This includes all types of sex, whether vaginal or anal.

• For injection drug use: PrEP lowers the risk by at least 74%, though combining prEP with clean syringe practices can offer even greater protection. 

One key factor in PrEP’s effectiveness is adherence – meaning how consistently it’s taken. Missing multiple doses can lower its protective effect, so staying on schedule is important. 

Daily vs. on-demand PrEP

For most people, PrEP is taken once a day as a pill. This is the standard, FDA-approved method, and it provides continuous protection as long as you keep taking it.

There’s also an on-demand or “2-1-1” PrEP method, which involves taking pills before and after potential exposure to HIV. This approach isn’t approved in the U.S. but is used in some other countries, mostly among men who have sex with men. If you’re considering this method, it’s best to talk to a healthcare provider to see if it’s right for you.

Regardless of the method, PrEP is most effective when used alongside other safer sex practices, like condoms and regular STI testing. It’s a powerful tool, but it works best as part of a broader approach to sexual health.

Who Should Take PrEP?

PrEP is for anyone who wants an extra layer of protection against HIV. While it’s especially recommended for people at higher risk, anyone who feels they could benefit from it should have access to it.

Who is considered at higher risk?

Health experts recommend PrEP for those who are more likely to be exposed to HIV, including:

• Men who have sex with men: This group remains disproportionately affected by HIV, making prEP a highly effective tool for prevention.

• Heterosexual individuals at risk: This includes people with an HIV-positive partner, those with multiple sexual partners, or those who don’t consistently use condoms. 

• People who inject drugs: Sharing needles or other injection equipment increases the risk of HIV transmission, and PrEP can offer additional protection.

• Anyone with a recent STI diagnosis: Having a sexually transmitted infection (STI) can increase the risk of HIV, making PrEP a good preventive measure.

Types of PrEP Medications

PrEP has come a long way since its introduction, and there are now multiple options to suit different needs and lifestyles. Whether you prefer a daily pill or an injectable treatment, there’s a PrEP option that can help you stay protected.

For people who don’t want to take a daily pill, Apretude (cabotegravir) is a newer PrEP option. This long-acting injectable is given every two months and provides the same high level of protection as daily PrEP pills. It’s a great alternative for those who struggle with daily medication adherence or simply prefer a less frequent dosing schedule.

Truvada vs. Descovy: What’s the difference?

The two most commonly prescribed PrEP pills are:

• Truvada (tenofovir disoproxil fumarate/emtricitabine): Approved for all people at risk for HIV, including men, women, and people who inject drugs. It’s the most widely used PrEP medication and has a long track record of effectiveness.

• Descovy (tenofovir alafenamide/emtricitabine): Approved for men and transgender women at risk for HIV. It’s not approved for use by cisgender women or people exposed to HIV through vaginal sex because its effectiveness hasn’t been studied as extensively in those populations. Descovy has a slightly improved safety profile for kidney and bone health, making it a good alternative for some individuals.

Both of these medications are taken once daily and require regular follow-ups with a healthcare provider. 

What is Doxy-PEP?

While not a PrEP medication for HIV, Doxy-PEP (doxycycline post-exposure prophylaxis) is an emerging STI prevention strategy. Taking a single dose of doxycycline after condomless sex has been shown to reduce the risk of bacterial STIs like syphilis, chlamydia, and gonorrhea in high-risk populations. Some experts see it as a valuable complement to PrEP for HIV prevention, though guidelines for its use are still evolving.

As research continues, more PrEP and STI prevention options are likely to emerge, making it easier than ever to take control of your sexual health. If you’re considering PrEP, talk to a healthcare provider to find the best option for you.

How to Get PrEP

If you’re ready to start PrEP, the process is straightforward and designed to ensure you’re getting the best care. Here’s what you need to know about getting a prescription, where to find it, and how to cover the cost. 

The steps to getting a PrEP prescription are as follows:

1. Consultation with a healthcare provider: You’ll need to meet with a doctor, nurse, or telehealth provider to discuss your risk factors and determine if PrEP is right for you.

2. Initial HIV testing: Since PrEP is only for HIV-negative individuals, you’ll need a lab test or rapid HIV test before starting. Many providers also check for STIs and kidney function.

3. Start taking PrEP: If everything checks out, you’ll get a prescription for a daily pill or an injectable PrEP option, depending on what works best for you.

4. Ongoing monitoring: Follow-up visits every three months ensure that PrEP is working for you. These visits typically include repeat HIV testing, kidney function tests (for pill-based PrEP), and STI screening. 

PrEP is accessible in various settings, including:

• Primary care doctors and clinics, both virtual and in-person

• Sexual health and LGBTQ+ clinics

• Community health programs

It’s important to note that PrEp medications require a prescription written by a healthcare provider.

How Much Does PrEP Cost?

Most insurance plans (including Medicaid) cover PrEp at little to no cost. Some plans may require a copay for lab tests or visits. Without insurance, the cost of PrEP can be high but several assistance programs can help:

• Gilead’s Advancing Access program offers financial help for Truvada and Descovy.

• Ready, Set, PrEP provides free PrEP to eligible individuals.

• State and local PrEP assistance programs can help cover medication and testing costs.

If cost is a concern, a healthcare provider or community clinic can help you find financial assistance programs that fit your situation. No one should be priced out of protecting their health.

Can You Get HIV From Someone on PrEP?

If your partner is taking PrEP consistently, the risk of them transmitting HIV to you is extremely low – but not completely zero. PrEP is designed to prevent HIV, not treat it, so the effectiveness depends on proper use and other risk factors.

While PrEP alone is an effective HIV prevention tool, using condoms adds extra protection – especially against other STIs and unintended pregnancy. Combining PrEP with condoms and regular STI testing is the best way to stay protected. 

What Happens If You Miss a Dose?

Consistency is key to maintaining protection when you’re on PrEP. The impact of a missed dose depends on which type of PrEP you’re taking – daily pills or injectable PrEP.

A single missed dose isn’t likely to put you at high risk, but frequent missed doses can weaken PrEP’s effectiveness. If you struggle with daily pills, consider long-acting injectables or set reminders to stay on track. If you’re unsure about your protection level, talk to a healthcare provider – they can help you stay protected and make adjustments if needed.

Does PrEP Help Treat HIV?

No, PrEP is for prevention, not treatment. IF someone already has HIV, PrEP won’t work as a treatment and should not be used in place of proper HIV medications. Antiretroviral therapy (ART) is the standard treatment for people living with HIV. It helps reduce the virus to undetectable levels and prevent transmission.

PrEP contains antiretroviral drugs, but in lower doses than what’s needed to manage HIV. If someone with undiagnosed HIV takes PrEP instead of ART, it won’t fully suppress the virus, and drug resistance could develop. This is why an HIV test is required before starting PrEP and must be repeated every three months.

If you’re concerned about HIV treatment options, seeing a healthcare provider as soon as possible is critical. ART has become highly effective, allowing people with HIV to live long, healthy lives while preventing transmission to others.

Are There Any Side Effects of PrEP?

PrEP is generally well tolerated, but like any medication, it can cause side effects. Most are mild and temporary, but there are some rare risks to be aware of. When starting PrEP, some people experience mild side effects that usually improve within a few weeks including:

• Nausea

• Headaches

• Fatigue

• Diarrhea

• Stomach discomfort

If these symptoms persist or worsen, talking to a healthcare provider can help determine the best course of action.

Some rare but serious risks associated with long-term PrEP use includes:

• Kidney function issues (typically associated with Truvada)

• Bone density loss (typically associated with Truvada)

Most side effects of PrEP are manageable and resolve on their own. Staying hydrated, taking PrEP with food, and discussing any concerns with your doctor can help. Routine checkups ensure that any potential risks, like kidney function or bone health changes, are caught early.

If you have concerns about side effects, your provider can help you choose the best PrEP option for your needs.

Can You Stop Taking PrEP?

You can stop taking PrEP, but it’s important to do so safely and with a plan for continued HIV prevention. If you decide to stop PrEP, consider the following:

• Talk to your provider: Discuss your reasons with a healthcare provider to ensure you’re making the best choice for your health.

• Consider the timing: To stay protected, continue taking daily PrEP for at least two days after your last potential HIV exposure (for anal sex) or 28 days after your last exposure (for vaginal sex or injection drug use).

• Get tested regularly: If stopping PrEP, continue getting tested for HIV and other STIs as recommended.

Alternatives for HIV prevention

If you stop taking PrEP, consider other prevention strategies, including:

• Condom use

• PEP, a 28-day emergency medication that can help prevent infection

• Your partner’s HIV treatment (U=U) 

If your partner is living with HIV and on effective treatment, their viral load may be undetectable, meaning they can’t transmit the virus (undetectable = untransmittable).

If your risk level changes in the future, you can always restart PrEP with guidance from your healthcare provider.

How Can LifeMD Help?

Protecting yourself against HIV and other sexually transmitted infections is essential. While LifeMD cannot prescribe PrEP, our team of licensed medical professionals can provide guidance on safe sex practices and offer prescriptions for other STIs, including chlamydia, gonorrhea, and more.

Make an online appointment today to get started.

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