If you have heart disease, chances are you’ve been prescribed medications to manage hypertension and protect your heart. One common medicine is losartan, a trusted drug used worldwide to improve heart and kidney health. But a common question is: Can losartan cause weight gain?

This article explores that question and more. We’ll walk through what losartan does, how it works, what side effects to expect, and how it compares to other heart medications that might be more likely to affect your weight.

It’s important to note that weight gain isn’t always a medical problem. For some people, trying to lose weight (or avoid gaining weight) may not be realistic or healthy. Many factors can affect weight gain or loss, so it’s a good idea to discuss any concerns with your doctor.

What Is Losartan?

Losartan is a type of medicine called an angiotensin II receptor blocker, or ARB for short. ARBs are used to lower high blood pressure, treat heart failure, and protect the kidneys — especially in people with diabetes.

So, how does losartan work? It blocks a natural chemical called angiotensin II, which normally makes blood vessels tighten. When losartan blocks this chemical, your blood vessels stay relaxed. That means your heart doesn’t have to work as hard, and blood can flow more freely through your body. Over time, this helps protect your heart, brain, and kidneys from damage caused by high pressure inside your arteries.

Losartan is often used when people can’t take ACE inhibitors, another type of blood pressure medicine that sometimes causes a dry cough or swelling in the throat. Because ARBs like losartan are less likely to cause those side effects, they’ve become a go-to option for many doctors.

Does Losartan Cause Weight Gain?

Losartan does not typically cause weight gain. That means people taking losartan aren’t more likely to gain fat or see their weight rise over time. The U.S. Food and Drug Administration (FDA) labeling for losartan does not list weight gain as a common or rare side effect.

That said, there’s one exception to be aware of: swelling from fluid retention, called edema. Though not very common, some people taking losartan may notice puffiness in their ankles, feet, or legs. This extra fluid can make you feel heavier or look bloated, even though it’s not true fat gain.

Doctors usually catch this swelling early and can adjust your dose, check your kidney function, or recommend a mild water pill (called a diuretic) to help you lose the extra fluid. If you notice swelling or a sudden change in your weight, it’s always a good idea to check in with your healthcare provider.

Understanding the Difference: Fat Gain vs. Fluid Gain

Not all weight gain is the same. Gaining fat happens when you take in more calories than your body uses, usually over weeks or months. This is the type of weight gain most people think of when they step on the scale.

Fluid retention, on the other hand, can happen much more quickly — sometimes even overnight. It’s your body holding on to water, often due to the amount of salt in your diet, hormones, or medications. When your ankles swell or shoes feel tighter, it’s often fluid that’s to blame.

A quick gain of 2 to 5 pounds in a week is more likely to be fluid than fat. This is especially important to watch for if you have heart failure or kidney disease. Your care team may ask you to track your weight every day and call them if you notice big changes like this.

What Side Effects Can Happen With Losartan?

Most people taking losartan don’t experience serious side effects. But like any medicine, it can cause problems in some people. The most common side effects of losartan include:

• Feeling dizzy when standing up quickly
• Headaches
• Muscle cramps
• Fatigue or tiredness
• Mild cough or throat irritation

These are usually mild and go away with time.

More Serious Side Effects

Some people may experience more serious effects, including:

• Swelling of the face, lips, or throat — a rare reaction called angioedema
• High potassium levels, which can affect your heartbeat
• Low blood pressure, especially if you’re dehydrated or taking other medications
• Kidney issues, especially in people with existing kidney disease

To catch these problems early, your doctor will likely order regular blood tests. These tests check your kidney function and potassium levels to make sure the medicine is working safely.

Do Other Heart Medications Cause Weight Gain?

Yes, and beta-blockers and calcium-channel blockers can cause weight gain, either in the form of fat or fluid retention.

Beta-Blockers

Beta-blockers, like atenolol, metoprolol, or propranolol, are often used for high blood pressure and heart conditions. They’re also known to cause weight gain. Research shows that people may gain an average of 2.6 pounds in the first few months of treatment.

The reasons for this weight gain are still being studied, but researchers believe it may be because beta-blockers slow down your metabolism and energy levels, making it harder for your body to burn calories.

Newer beta-blockers like carvedilol and nebivolol seem to cause less weight gain and may be a better option if weight is a concern.

Calcium-Channel Blockers

Some other heart medications, like calcium-channel blockers, can also lead to fluid retention. While this isn’t true fat gain, it may still cause your weight to increase temporarily.

What Can You Do if You Notice Weight or Swelling?

If you’re taking losartan and your weight starts to change, here’s what you can do:

• Track your weight daily, at the same time each morning, using the same scale.
• Check for swelling, especially in your feet, ankles, or hands.
• Limit salt, which can cause your body to hold on to more fluid.
• Stay active. Even light walking may help ease swelling.
• Drink water unless your doctor tells you to limit fluids.
• Call your doctor if you gain more than a few pounds quickly or feel more swollen than usual.

It’s also helpful to write down any symptoms you notice. This can help your care team decide if your medication needs to be adjusted.

Talk With Others Who Understand

On MyHeartDiseaseTeam, the social network for people with heart disease and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

Have you noticed any weight gain while taking losartan? Share your experience in the comments below, or start a conversation by posting on your Activities page.