HIV is treated with antiretroviral therapy (ART), a combination of medications taken daily or, in some cases, given as an injection every one to two months. When taken consistently, ART suppresses the virus to undetectable levels in the blood, preserving immune function and preventing transmission to sexual partners. Treatment is lifelong, but modern regimens are simpler and more forgiving than those available even a decade ago.
How Antiretroviral Therapy Works
HIV hijacks immune cells and uses their machinery to make copies of itself. ART works by blocking this process at different stages. The most commonly prescribed drugs today are integrase inhibitors, which prevent HIV’s genetic material from inserting itself into the DNA of your immune cells. Without that step, the virus can’t take over a cell and force it to produce more virus.
Other drug classes block earlier steps, like the virus attaching to or entering a cell, or the conversion of its genetic code into a form your cells can read. Some block later steps, preventing newly made viral particles from maturing into infectious copies. A standard regimen combines two or three drugs that attack different stages, making it extremely difficult for the virus to develop workarounds against all of them at once.
What Treatment Looks Like Day to Day
Most people start on a single pill taken once a day. These combination tablets pack two or three drugs into one dose. For people who are already virally suppressed and have no history of treatment failure, a long-acting injectable option is available. It involves two shots given at the same clinic visit, either monthly or every two months, replacing daily pills entirely. You need to be on a stable oral regimen first to confirm the medications work for you before switching to injections.
Modern regimens are more forgiving of imperfect adherence than older ones. A real-world study found that integrase inhibitor-based regimens achieved viral suppression in 90% of lab tests when adherence was around 75%, compared to 87% for protease inhibitor-based regimens and 99% for older drug combinations. That said, consistent adherence still matters. Missing doses too often raises the risk of viral rebound and drug resistance, which can permanently limit your treatment options.
Reaching Undetectable Levels
The goal of treatment is to reduce the amount of virus in your blood to a level so low that standard lab tests can’t detect it. Most people reach this point within one to six months of starting therapy. Once you achieve and maintain an undetectable viral load, you cannot transmit HIV to sexual partners. The CDC states this plainly: a person on treatment with an undetectable viral load has zero risk of sexual transmission. This principle, known as Undetectable = Untransmittable (U=U), has been confirmed in studies involving thousands of couples over tens of thousands of sex acts without a single linked transmission.
Maintaining undetectable status requires staying on your medication and getting viral load tests on a regular schedule, typically every three to six months once you’re stable.
Life Expectancy on Treatment
Starting treatment early dramatically changes the long-term picture. A large collaborative analysis of European and North American cohorts, published in The Lancet HIV, estimated that a 40-year-old man who started ART after 2015 could expect to live to about 77, compared to roughly 81 in the general population. For women, the estimate was about 79 versus nearly 86 in the general population. The gap narrows further for people who begin treatment while their immune system is still strong: women who started ART with high immune cell counts had a life expectancy within about four years of the general population.
Starting late carries a steep cost. People who began treatment with severely depleted immune systems had life expectancies roughly 15 years shorter than those who started early, even with access to the same medications. This is the single strongest argument for testing and beginning treatment as soon as possible after diagnosis.
Side Effects and Weight Changes
Modern HIV medications are far better tolerated than earlier generations, but they aren’t side-effect free. The most discussed issue with current first-line drugs is weight gain. About 13% of people starting ART experience more than 10% weight gain within the first year. This effect is most pronounced with integrase inhibitors, the same drug class that’s easiest to take and most forgiving of missed doses.
The weight gain isn’t just cosmetic. People who gained more than 10% of their body weight in the first year had a higher risk of developing type 2 diabetes, metabolic syndrome, and cardiovascular problems in the following year. One large study of veterans found that every five pounds of weight gain was associated with a 14% increased risk of diabetes for people with HIV, compared to 8% for people without HIV. This means weight monitoring is an important part of ongoing care, and your provider may recommend dietary changes, exercise, or in some cases, switching to a regimen associated with less weight gain.
Drug Resistance Testing
Before you start your first regimen, your provider will order a resistance test. This analyzes the specific strain of HIV you carry to determine which drugs it’s already resistant to, often because the person who transmitted the virus was on treatment that the virus had partially evolved to evade. The results guide which combination of drugs will work best for you.
If you’ve previously used certain prevention medications like long-acting injectable PrEP, your provider will specifically test for resistance to the drugs in those formulations. Resistance testing is also repeated if your viral load rebounds while on treatment, ideally while you’re still taking your current medications so the resistant virus is actively replicating and detectable. For pregnant individuals, testing is recommended both before starting therapy and if viral load becomes detectable during pregnancy.
Options for Drug-Resistant HIV
For people who have cycled through multiple regimens and developed resistance to several drug classes, a newer option exists. A first-in-class medication that targets the virus’s protective protein shell works differently from all previous drug classes, interfering with multiple stages of the viral life cycle at once. It’s given as two injections every six months after an initial loading period, and it’s combined with whatever other active drugs remain available.
In a clinical trial of 72 people with multi-drug resistant HIV, 81% to 83% achieved a fully suppressed viral load within six months. This represents a significant advance for people who had previously run out of effective treatment options. The six-month dosing interval also reduces the burden of daily adherence for a population that has often struggled with complex, multi-pill regimens for years.
Starting Treatment Early
Current guidelines recommend starting ART as soon as possible after diagnosis. In many clinics, treatment begins the same day as diagnosis or within days. Resistance test results may take a week or more to come back, but providers typically start a regimen that’s effective against the vast majority of circulating strains and adjust later if needed. For people diagnosed during acute infection or during pregnancy, this same-day approach is especially important.
The practical difference between starting early and waiting is measurable in years of life. It also determines how well your immune system recovers. People who begin treatment with higher immune cell counts recover more fully and face fewer long-term complications, including lower rates of certain cancers, kidney disease, and cardiovascular problems that HIV-related inflammation can drive even when the virus is controlled.