Saxenda® and Victoza® side effects: what to expect

Saxenda® and Victoza® side effects are on your mind before you even open the pen. That worry is fair, and it is common.

Maybe a friend felt queasy the first week. Maybe you read a scary list online and stopped reading halfway. It is a lot to take in.

Here is the calmer truth. Most effects are known, most are mild, and most ease with time. A few need quick attention, and this page shows you which.

Saxenda® and Victoza® side effects: the common ones

Saxenda® and Victoza® both use liraglutide, a daily shot under the skin. Because the medicine is the same, the common side effects look a lot alike.

Most of them involve your stomach. The FDA labels list nausea, diarrhea, vomiting, and constipation as the effects people report most.

The two brands are approved for different goals, though. Saxenda® is approved for weight management. Victoza® is approved for type 2 diabetes, and to lower heart risk in some adults.

That difference matters for one effect in particular. Victoza® is often used with other diabetes medicines, and some of those can raise the risk of low blood sugar.

Common effect (FDA label §6.1)	Saxenda® (weight management)	Victoza® (type 2 diabetes)
Nausea	Listed as a common effect	About 20% of people
Diarrhea	Listed as a common effect	About 12% of people
Vomiting	Listed as a common effect	About 9% of people
Constipation	Listed as a common effect	About 5% of people
Dyspepsia (upset stomach)	Listed as a common effect	About 7% of people
Decreased appetite	Not among the top listed	About 9% of people
Headache	Listed as a common effect	Not among the top listed
Low blood sugar	Listed as a common effect	Rises with insulin or a sulfonylurea

From the FDA labels, section 6.1. Victoza® figures are the reactions reported in 5% or more of people. Saxenda® effects are those the label names as common.

Read the table as a guide, not a promise. Many people feel fine, and some feel more than others. Your own list may be shorter than you expect.

The same medicine can feel very different from one person to the next. Your first week is not a rule for your whole plan.

How Saxenda® side effects tend to show up

Saxenda® is the liraglutide brand for chronic weight management. It is a daily shot, and the dose climbs slowly on a set schedule.

The FDA label lists nausea, diarrhea, constipation, and vomiting as common. It also names headache, dyspepsia, fatigue, dizziness, and injection-site reactions.

Low blood sugar and abdominal pain are on the Saxenda® list too. Most of these effects are mild, and most ease as your body adjusts to each step.

The slow dose climb is on purpose. Saxenda® starts low and rises each week, which gives your stomach time to settle before the next step.

How Victoza® side effects compare

Victoza® is the liraglutide brand for type 2 diabetes. It is also a daily shot, and it can lower heart risk in some adults with heart disease.

The FDA label gives clear numbers for Victoza®. Nausea showed up in about 20% of people, diarrhea in about 12%, and vomiting in about 9%.

The label also lists decreased appetite in about 9%, dyspepsia in about 7%, and constipation in about 5%. These are the reactions reported in 5% or more of people.

Low blood sugar is the effect that sets Victoza® apart. On its own, the risk is low. With insulin or a sulfonylurea, that risk goes up, so your care team may adjust those doses.

Low blood sugar is not about Victoza® alone. It is about the whole mix of medicines you take together.

Why the two brands share so many side effects

Saxenda® and Victoza® are both liraglutide. The molecule is identical, so the way it acts on your body is the same.

Liraglutide slows how fast your stomach empties. That is part of why it can curb appetite, and also why nausea and other stomach effects are common early on.

The main difference is the goal, not the molecule. Saxenda® is dosed for weight, while Victoza® is dosed for blood sugar and heart risk.

Both are once-daily shots, which is worth noting. Some other GLP-1 medicines are taken once weekly, but liraglutide is a daily routine.

What the first few weeks can feel like

Both brands start at a low dose and step up over the first weeks. Here is how the FDA-labeled schedules climb, and why the ramp is gentle.

1. Week 1: Saxenda® starts at 0.6 mg daily. Victoza® also starts at 0.6 mg daily, a setup dose that is not meant to control blood sugar.

2. Week 2: Saxenda® rises to 1.2 mg daily. Victoza® moves to 1.2 mg daily, its first working dose.

3. Week 3: Saxenda® rises to 1.8 mg daily. Victoza® may go to a 1.8 mg daily maximum after at least one week at 1.2 mg.

4. Week 4: Saxenda® rises to 2.4 mg daily on its way to the full dose.

5. Week 5 and on: Saxenda® reaches its 3 mg daily maintenance dose. Stomach effects often ease as you settle at each step.

This slow climb is the point. Each small step gives your body time, so nausea and loose stools tend to fade rather than pile up.

If a step feels rough, your care team may hold you there longer. There is no prize for reaching the top dose fast.

The dose is a starting point, not a finish line. It moves on a schedule, not on how you feel that one day.

Serious warnings you should know

Most Saxenda® and Victoza® side effects are mild. A few are serious, and knowing them helps you act fast if they ever show up.

Both brands carry a boxed warning about the thyroid. In animal studies, liraglutide caused thyroid C-cell tumors.

It is not known if this happens in people, including medullary thyroid cancer. Because of this, neither brand is for anyone with a personal or family history of MTC or MEN 2.

Pancreatitis is a serious risk to watch with GLP-1 medicines as a class. Warning signs include severe belly pain that may spread to your back, with or without vomiting.

If you feel pain like that, stop the medicine and get help right away. Your prescriber will check what is going on.

Dehydration is another risk worth watching. Across GLP-1 medicines, reports describe acute kidney injury, sometimes needing dialysis, mostly when nausea, vomiting, or diarrhea led to fluid loss.

When to call your prescriber

Most side effects pass on their own. Some are signals to reach out, and a few mean you should get help right away.

Nausea, vomiting, or diarrhea that does not go away, or that stops you from keeping fluids down.

Signs of dehydration, such as very dark urine, dizziness, or feeling faint.

Severe belly pain that may spread to your back, with or without vomiting.

A lump or swelling in your neck, trouble swallowing, or a hoarse voice that lasts.

Shakiness, sweating, or confusion that could be low blood sugar, especially with other diabetes medicines.

When in doubt, it is always okay to call. A quick check-in can settle your mind or catch a problem early.

3. Pi-Sunyer X, et al. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management (SCALE). N Engl J Med. 2015;373:11-22. PMID 26132939. NCT01272219.

Frequently asked questions

Are Saxenda® and Victoza® side effects the same?

They are very similar, because both brands use liraglutide. The FDA labels list nausea, diarrhea, vomiting, and constipation as the most common effects for each. The biggest difference is low blood sugar. Victoza® is used for type 2 diabetes and is often taken with other diabetes medicines, and some of those can raise that risk.

Will the nausea from Saxenda® or Victoza® go away?

For most people, yes. Nausea tends to be strongest early, when the dose first climbs. Both brands start low and step up slowly on a set schedule, which gives your stomach time to adjust. As you settle at each step, the queasy feeling often fades. If it does not ease or you cannot keep fluids down, call your prescriber.

Why do Saxenda® and Victoza® upset the stomach?

Liraglutide slows how fast your stomach empties. That effect helps curb appetite, but it can also cause nausea, a full feeling, and loose or hard stools early on. Because both brands share the same molecule, this stomach effect shows up with each one. The slow dose climb is designed to keep these effects gentle over the first weeks.

Is low blood sugar a common Victoza® side effect?

On its own, Victoza® has a low risk of causing low blood sugar. The risk rises when it is taken with insulin or a sulfonylurea, which are other diabetes medicines. If you use those, your care team may lower their doses. Watch for shakiness, sweating, or confusion, and treat low blood sugar the way your prescriber has told you.

What is the boxed warning on Saxenda® and Victoza®?

In animal studies, liraglutide caused thyroid C-cell tumors. It is not known if Saxenda® or Victoza® causes these tumors, including medullary thyroid cancer, in people. Because of this, neither brand is for anyone with a personal or family history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Your care team will ask about this before you start.

When should I get help right away?

Get help fast if you have severe belly pain that may spread to your back, with or without vomiting. Reach out if nausea, vomiting, or diarrhea does not stop, or if you cannot keep fluids down. Also call about a neck lump, trouble swallowing, or a lasting hoarse voice. These are signals worth a quick call to your prescriber.

Do Saxenda® and Victoza® cause dehydration?

Not directly, but they can lead to it. When nausea, vomiting, or diarrhea causes fluid loss, you can become dehydrated. Across GLP-1 medicines, reports describe acute kidney injury tied to that fluid loss, sometimes needing dialysis. Sipping fluids helps, and you should tell your prescriber right away if stomach effects do not go away.

Important: This page is for education only and is not medical advice. Any medicines named here are available by prescription. Always talk to a licensed clinician about medicines, symptoms, or anything you are considering.