Does Biktarvy Cause Weight Gain? HIV Medicines, Belly Fat and What You Can Do

You started HIV treatment, your viral load dropped, you feel well again, and then the scales start creeping up. You are not imagining it, and you are not alone. Weight gain is one of the most talked-about side effects of modern HIV medicine, and it is now listed as a common side effect in the European leaflets for Biktarvy, Dovato and Triumeq³⁴⁵.

Here is what the research actually shows, why some of that weight is a good sign, and what you can do about the rest.

What the big studies found

The clearest picture comes from a pooled analysis of eight clinical trials, covering more than 5,000 people who started HIV treatment between 2003 and 2015¹. It found that:

• People gained more weight in the more recent trials, on the newer regimens.
• Integrase inhibitors were linked with more weight gain than older drug classes, and dolutegravir and bictegravir with more than elvitegravir.
• Tenofovir alafenamide (TAF) was linked with more weight gain than the older tenofovir disoproxil fumarate (TDF), abacavir or zidovudine.
• Among the older NNRTI drugs, rilpivirine was linked with more weight gain than efavirenz.

A large trial in South Africa, called ADVANCE, showed the same pattern in real numbers². Over the first 48 weeks, people starting dolutegravir with TAF gained about 6.4 kg on average. Those starting dolutegravir with TDF gained about 3.2 kg, and those on an older efavirenz-based pill gained about 1.7 kg. Women gained more than men.

Two things are worth saying clearly. First, these are averages: plenty of people on these medicines gain little or nothing. Second, the researchers themselves say the exact reasons are still not known¹.

Some of that weight is a healthy sign

Untreated HIV burns energy. The immune system is fighting all the time, appetite often drops, and many people lose weight before they are diagnosed. When treatment brings the virus under control, the body stops spending so much energy on that fight, appetite comes back, and weight returns. Doctors call this the “return to health” effect, and the pooled analysis points to it as part of the story¹.

That is why the people most likely to gain weight in the studies included those who started treatment with a low CD4 count or a high viral load, in other words, people who were more unwell to begin with¹.

The question your team will think about is not “has my weight gone up?” but “has it gone beyond a healthy level for me?”

Who seems to be more affected

Across the trials, more weight gain was seen in¹²:

• women
• Black participants
• people who started treatment with a low CD4 count or a high viral load

US treatment guidelines add older age to that list⁸.

Nobody fully understands why. Being in one of these groups does not mean you will gain weight, but it is a good reason to keep an eye on it from the start.

Biktarvy, Dovato, Triumeq and dolutegravir: what is known

• Biktarvy contains bictegravir and TAF, both linked with weight gain in the studies above. The European leaflet lists weight gain as a common side effect, which means it may affect up to 1 in 10 people³.
• Dovato contains dolutegravir and lamivudine. Its European leaflet also lists weight gain as common⁴. In a US trial where people switched to Dovato from a TAF-based regimen, “weight increased” was reported as a side effect in 3%⁶.
• Triumeq contains dolutegravir with abacavir and lamivudine, and its leaflet lists weight gain as common too⁵.
• Truvada (TDF). People sometimes notice they lose a little weight on Truvada, or gain some when they move from Truvada to a TAF-based pill such as Descovy. That fits the finding that TDF is linked with less weight gain than TAF¹. We explain the two tenofovirs in Truvada vs Descovy.

The European product information for all three regimens also carries a general note: weight, blood fats and blood sugar may all rise during HIV treatment³⁴⁵. That is why the checks below matter.

Why stopping or skipping doses is not the answer

It is tempting to blame the tablet and cut back on it. Please do not. Skipping doses lets the virus start copying again and can lead to drug resistance, which is far harder to fix than weight gain⁷. If the weight is bothering you, the right move is to raise it with your HIV team. Our guide on missed doses explains why the daily rhythm matters so much.

Would switching regimens help?

This is the question most people ask. The US treatment guidelines are clear: HIV medicines should not be chosen, or switched, just to prevent or reduce weight gain, because the available evidence suggests that approach does not work⁸. The choice should be based on what keeps the virus best under control for you.

You may still read about the PASO-DOBLE trial, which compared switching to Dovato with switching to Biktarvy. Both groups gained some weight over 96 weeks, but the Dovato group gained less, and more people on Biktarvy gained over 5% of their starting weight⁹. That is useful to know, but gaining less is not the same as losing weight, and the people in that trial had not taken either drug before.

If weight is one of several reasons you are thinking about a change, it is a fair thing to raise. Your team will weigh it against the reasons your current regimen was chosen, such as hepatitis B, drug resistance or other medicines you take. Our comparison of Dovato, Biktarvy and Triumeq sets the options side by side.

Belly fat: where does the weight go?

Many people notice the change first at their waist, and “Biktarvy belly fat” is a common search. The studies above measured total weight, so there is less clear evidence on where the extra weight settles for each medicine.

What we do know is that fat around the middle matters more for your health than the number on the scales, because it is the kind most linked with heart disease and type 2 diabetes. The European leaflets also note that weight, blood fats and blood sugar can all rise during HIV treatment³⁴. So a growing waist is a good reason to ask for your blood pressure, blood sugar and cholesterol to be checked, rather than a reason to stop treatment.

What actually helps

The steps that help are the same ones that help anyone, but they matter a little more when you are on long-term treatment:

• Weigh yourself before and after starting, and every few weeks for the first year, so you notice a trend early rather than a year later.
• Ask for the routine health checks: blood pressure, blood sugar and cholesterol. Weight gain matters most when it starts to push these up.
• Measure your waist now and then, as well as weighing yourself.
• Move more, in ways you enjoy. Our beginner’s guide to working out is a good place to start.
• Look at what you eat when appetite returns. Feeling hungry again after treatment starts is normal. It helps to plan regular meals rather than graze.
• Sleep and mood count. Poor sleep and low mood both make weight harder to manage. Mention them if they are a problem; some HIV medicines can affect sleep too.

For more on how physical activity supports long-term health on medicines, see exercise and health.

Frequently asked questions

Does Biktarvy cause weight gain?

It can. Weight gain is listed as a common side effect in the European leaflet, and both of its main ingredients, bictegravir and TAF, have been linked with more weight gain than older HIV medicines. Many people on Biktarvy gain little or no weight.

Why does Truvada cause weight loss?

Truvada contains the older form of tenofovir, TDF, which studies have linked with less weight gain than the newer TAF. Some people lose a little weight on it, and some gain a little when they switch to a TAF-based pill. The reason is not fully understood.

Will switching off dolutegravir make me lose weight?

Probably not. US guidelines advise against choosing or switching HIV medicines to prevent or reduce weight gain, because the evidence suggests it does not work. Discuss it with your HIV team, who will consider why your current regimen was chosen.

Is Biktarvy hard on the body?

For most people, no. It is one of the most widely used HIV pills, and the common side effects (headache, diarrhoea, feeling sick, tiredness, strange dreams, weight gain) are usually mild. Your clinic checks kidney function and other blood tests while you take it.

Does tenofovir make you gain weight?

It depends which form. Tenofovir alafenamide (TAF), found in Biktarvy and Descovy, has been linked with more weight gain than the older tenofovir disoproxil fumarate (TDF) found in Truvada. Regimens based on TDF are among those with the least weight gain.

Is all the weight gain caused by the medicine?

No. Part of it is often the “return to health” effect, as your body recovers from untreated HIV. The rest is a mix of the medicines, your genes, diet, activity and other factors.

Should I stop my HIV medicine if I am gaining weight?

No. Stopping or skipping doses can let the virus come back and become resistant. Talk to your HIV team instead.

Sources & references

1. Sax PE, Erlandson KM, Lake JE, et al. Weight Gain Following Initiation of Antiretroviral Therapy: Risk Factors in Randomized Comparative Clinical Trials. Clinical Infectious Diseases. 2020;71(6):1379-1389.
2. Venter WDF, Moorhouse M, Sokhela S, et al. Dolutegravir plus Two Different Prodrugs of Tenofovir to Treat HIV (ADVANCE). New England Journal of Medicine. 2019;381:803-815.
3. European Medicines Agency. Biktarvy: product information and package leaflet.
4. European Medicines Agency. Dovato: product information and package leaflet.
5. European Medicines Agency. Triumeq: product information and package leaflet.
6. US National Library of Medicine, DailyMed. Dovato prescribing information.
7. HIV.gov. Taking Your HIV Medicine as Prescribed.
8. US Department of Health and Human Services, Clinicalinfo. Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents: Weight Gain in People With Treated HIV. Updated 25 September 2025.
9. ViiV Healthcare (manufacturer). PASO DOBLE trial data, including 96-week weight results.

Related reading

• Biktarvy explained
• Dolutegravir-based treatment: your first 90 days
• Truvada vs Descovy
• Dolutegravir medicines and tenofovir alafenamide medicines

This content is for informational purposes only and is not medical advice. Weight change can have many causes, and your HIV team can check what is behind yours. Never stop or change HIV medicine without talking to them. Used as prescribed by a licensed medical professional.