If you're a member of the LGBTQ community, you've very likely heard of—and are perhaps even on—PrEP. It's short for "pre-exposure prophylaxis," a fancy way of saying that you're taking a daily pill, either Truvada or Descovy, to prevent yourself from contracting HIV through sexual intercourse. Some have jokingly called it "the gay man's birth control," but it also works for sexually active cisgender women and transgender people.

And boy, does it work. By this point, eight years after Truvada was approved by the U.S. Food and Drug Administration, multiple large studies have shown that, when taken daily (or even a few days before and after having sex), PrEP reduces one's chance of contracting HIV by nearly 100 percent. (Of course, that doesn't mean anyone has to go on, or stay on, PrEP to stay HIV-negative. That's a decision that only you can make after having a conversation with your health provider, friends, and sexual partners about how at risk you are and what kinds of protection you want to use.)

Nevertheless, in the past year or so, you may have noticed a proliferation of ads on Facebook and other social media platforms asking if you’ve been “harmed” or “injured” by PrEP or Truvada, and urging you to join class-action lawsuits against its maker, the pharmaceutical giant Gilead. If so, you may have been left wondering if you should go off it, or if you should never go on it to begin with.

So just how legitimate are these ads, and how concerned should you be? Well, first it's important to note that, yes, there are a few lawsuits out there against Gilead, the company that makes both Truvada and Descovy, but they pertain to the use of those drugs for treatment in HIV-positive people—even more specifically to the allegation that Gilead withheld Descovy from the market for many years to first profit fully from Truvada, despite having data showing that Descovy might, in some narrow regards, be safer than Truvada. The ads, however, ask if you've been harmed by the use of PrEP. In reality, there isn't a lawsuit pending against PrEP. The ads are actually from opportunistic law firms that hoped they might one day profit from a suit against PrEP and were looking for potential clients preemptively.

Well-known HIV activist Peter Staley is suing Gilead, but for antitrust patent reasons, not because he thinks PrEP is ineffective or harmful. "While it's true that there are legitimate lawsuits about how Truvada harmed some people living with HIV, many of the ads on Facebook are just exploitative speculations from ambulance-chasing law firms that have not filed cases," he says. "And those ads are putting a dangerous chill on efforts to expand PrEP usage, especially among young gay men who could benefit from PrEP the most."

Okay, good to know. But is PrEP harmful in any way?

Well, first of all, harm shouldn't be confused with side effects. Almost all drugs have side effects, especially if taken at high doses or consistently over time—even something as benign as aspirin. In fact, if you want a metric, a UCLA study from a few years ago found that taking daily PrEP was as safe as taking a daily aspirin. You will always have to weigh the benefits of any drug against its side effects.

As for actual side effects, it is well documented that, in the 16 years that Truvada has been on the market, kidney and bone problems—often minor—have emerged in a very small percentage of people with HIV who took the drug for treatment, not for prevention. An extremely large study looking at groups of up to 10,000 HIV patients found the same number of or even fewer kidney issues in patients taking regimens with tenofovir, or TDF (one of the two drugs that make up Truvada, the other being emtricitabine, or FTC), than in those without it. It also found that levels of bone fracture were higher than average in some regimens containing TDF, but lower in others.

All of this may point to the fact that these problems had something to do with long-term HIV infection itself—or with taking TDF in combination with other drugs that boost levels of TDF in the body. In which case users taking Truvada for prevention shouldn't be alarmed.

"These lawsuits were taking a partial bit of evidence and extrapolating it to generate false mass fear for people who were using these meds as PrEP when there's no evidence that PrEP is unsafe, or even that Descovy is safer than Truvada," says Jeremiah Johnson, who studies PrEP at the HIV research and advocacy nonprofit Treatment Action Group.

Johnson raises another important point. Truvada and Descovy are both FDA-approved and hence generally covered by health plans, but Gilead has, based on some very narrow biomarkers (blood tests), promoted Descovy as the "safer" choice when it comes to kidney and bone issues. But again, Gilead is currently being sued for withholding supposedly safer Descovy for years so that it could exhaust its exclusive rights to lookalike Truvada first, then reboot its market exclusivity with "new and improved" Descovy. File this under “Shady Things That Pharma Does to Hold Onto Profits.”

Still, despite all that, a 2018 study found no toxicity-related differences between the two drugs when they were not used in combination with other drugs—which only happens with people with HIV, not those trying to protect themselves from getting it. Some studies have shown that Descovy might present a higher risk of weight gain and elevated lipids (blood fats like cholesterol) than Truvada does, but that's the extent of any differences between the two.

The bottom line: At this point, we've seen no clinical evidence that users are putting themselves at great risk by going on PrEP, regardless of whether they take Truvada or Descovy. Moreover, if you are on PrEP, you should be getting your labs done every three months, which would mean any issues related to your kidneys, bones, or cholesterol would likely show up long before they became a real danger—in which case you could stop using PrEP.

It's also worth noting that "PrEP" refers to a practice—like birth control—and not to a specific drug. Even as we speak, more versions of PrEP, including long-acting oral and injectable ones, are in the pipeline, meaning that Truvada and Descovy may not be our only choices for much longer.

Even then you'll have to ask yourself, "Am I at risk enough for HIV that it's worth the time, trouble, possible side effects (which can include headaches and nausea), and expense (though it can be secured for free even without health insurance) of going on PrEP?" Again, only you can decide.

One thing you should not do, however, is base your decision on ads you see while scrolling through your Facebook feed.

"They've stirred up a lot of unnecessary worry," says Dr. Judith Feinberg, chair of the HIV Medicine Association. "They really undermine the use of PrEP, which has clearly shown to be highly effective. PrEP has not been shown to pose a significant health concern to the vast majority of people taking it. It's not ethical to frighten people out of getting care that is clearly to their benefit."

For more information on PrEP, speak with a trusted health provider.