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GLP-1 receptor agonist · safety

Liraglutide side effects

The liraglutide side effects reported most often are nausea, diarrhea and constipation. The full list is below, with the FDA label cited at the bottom of the page.

Rarer, but worth being able to spot: acute pancreatitis, acute gallbladder disease and acute kidney injury due to volume depletion, and 1 more in the table below. Liraglutide also carries a boxed warning for risk of thyroid C-cell tumors.

These effects tend to cluster at the start and after each dose increase, and to settle down while the dose stays the same.

Liraglutide is the drug in the daily injection pens Victoza and Saxenda. The brands have different approved uses and dose schedules. People take Victoza for type 2 diabetes and Saxenda for long-term weight management.

Both products have FDA approval. Their labels use different maximum doses, so one schedule cannot stand in for the other.

Also sold as Victoza and Saxenda — one molecule, so these reactions apply to every brand of it.

Further down: the full list with frequencies · when to get medical help · questions

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewerReviewed 2026-08-15open the primary sources

At a glance

Common reactions listed

6

Serious reactions listed

4

Boxed warning

Yes

Strongest source

FDA label

The counts show how many distinct reactions the FDA label names. The percentages show how often a reaction appeared in a study group, not the chance that it will happen to you.

Boxed warning

Risk of thyroid C-cell tumors

Liraglutide caused thyroid C-cell tumors in rats and mice. Whether it causes these tumors, including medullary thyroid carcinoma, in humans is unknown. The labels contraindicate use with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

Source: Saxenda (liraglutide) injection — FDA-approved Prescribing Information (DailyMed) · retrieved 2026-08-15

Common reactions

The full list, with the frequency band the FDA label gives for each one.

◆ Common reactionslabel frequency
ReactionFrequency
NauseaReported in Saxenda trials (≥5%)
DiarrheaReported in Victoza trials (≥5%)
ConstipationReported in Saxenda trials (≥5%)
VomitingReported in Victoza trials (≥5%)
Decreased appetiteReported in Victoza trials (≥5%)
Injection-site reactionsReported in Saxenda trials (≥5%)

Serious reactions to watch for

These are rarer, and they are the ones clinicians monitor for. Seek medical care if you have symptoms.

◆ Serious — monitorwarning/precaution
ReactionFrequency
Acute pancreatitisSerious — both product labels warn
Acute gallbladder diseaseSerious — both product labels warn
Acute kidney injury due to volume depletionSerious — both product labels warn
Severe hypersensitivity reactionsSerious — both product labels warn

FDA labelEvery reaction above comes from the product’s regulatory document. These are label facts, not personal advice.

When to seek medical care

Each one below is a serious reaction from the table above, written as the signs you would actually notice. Spotting them is the job of this section; working out what they mean is a clinician’s.

Acute pancreatitis

Urgent

Signs: Severe pain high in the abdomen that will not let up and may bore through to the back, often with nausea or vomiting that does not settle. People describe it as different from ordinary post-dose nausea, in that it does not come and go with meals.

The prescribing information lists this as a reaction that needs medical assessment. Call a clinician without waiting for the next appointment, or emergency services if the pain is severe.

Gallbladder disease

Prompt

Signs: Pain in the upper right side of the abdomen, sometimes after eating, with fever, yellowing of the skin or the whites of the eyes, unusually pale stools, or dark urine.

These are signs to get seen promptly rather than wait and watch.

Acute kidney injury from dehydration

Prompt

Signs: Vomiting or diarrhea bad enough that you cannot keep fluids down, passing much less urine than usual, dizziness when you stand up, or unusual weakness.

The label links the risk to dehydration, so ongoing fluid loss is worth reporting early. A clinician can check kidney function.

Severe hypersensitivity reaction

Urgent

Signs: Swelling of the face, lips, tongue or throat, trouble breathing or swallowing, a rash or hives spreading fast, or suddenly feeling faint.

This is the one on the list that does not wait. Call emergency services immediately rather than a clinic.

EmergencySome symptoms should not wait for an appointment. Call emergency services (911 in the US) if they are severe, getting worse fast, or involve trouble breathing, chest pain, fainting or confusion.

3Read deeperTiming, evidence limits, and product context

When these effects tend to occur

GLP-1 labels and trial reports place stomach and gut effects most often at the start and after dose increases. A later increase can bring that early pattern back.

The same sources describe most of these effects as temporary — showing up after a step and easing off while the dose stays put. That is the pattern across whole trial populations. It is not a promise about you, and the sources do not commit to how long the easing takes.

Making side effects easier to discuss

None of this is a recommendation, and none of it is treatment. These are the side-effect topics clinicians and drug labels tend to raise. They are written down here so your conversation with a prescriber starts further along than it otherwise would.

Meal size and pace
Portion size and how fast you eat are usually the first things raised when nausea tracks with meals. They come up because they are things you can describe precisely at your next appointment, which makes them useful information either way.
Fluids
Fluid intake comes up in almost every side-effect conversation. The reason is already on this page: where kidney injury appears in the serious list, dehydration is the route named. Vomiting and diarrhea are what lose fluid. That is why clinicians want to hear about them early rather than have you put up with them quietly.
Noticing patterns rather than guessing
Clinicians often suggest keeping track of what came before a bad day — the meal, the timing relative to the injection, how recently the dose changed. A specific account is worth more at an appointment than a vague one, and it is the part only the person taking the compound can supply.
How fast the dose moves
How quickly the dose goes up is a clinician’s call and belongs in that conversation, not on this page. Approved schedules set a minimum time at each step and treat the next step as conditional on the current one going well. Staying longer at a step is a recognized option, and the prescriber is the one who uses it.
Constipation as its own topic
Constipation usually gets discussed separately from nausea, because what helps is different and because anything reached for over the counter interacts with the rest of a medicine list. That makes it a question for a clinician or pharmacist rather than a search box.
Reporting rather than enduring
A side effect is information, not a test you failed. Clinicians want to hear about reactions early. They can hold a step, change the timing or look for another cause. The right choice depends on your symptoms, history and other medicines.

Starting, holding, changing, pausing or stopping a dose is a decision for the person who prescribes it.

Victoza and Saxenda side effects

Victoza and Saxenda contain the same molecule, but the rows above are not a blended incidence table. Each frequency line names the product label that reported it. The labels studied different populations and use different schedules, so their percentages remain product facts.

Victoza label

Keep this denominator separate

Adults with type 2 diabetes, alongside diet and exercise, to improve blood sugar control. Its labeled maximum is 1.8 mg daily. The safety table belongs to those trials and that schedule.

Read the Victoza schedule

Saxenda label

Keep this denominator separate

Adults with obesity, or adults with overweight and at least one weight-related condition, alongside a reduced-calorie diet and more physical activity, to cut excess body weight and hold the loss long term. Its labeled maximum is 3 mg daily. The safety table belongs to those trials and that schedule.

Read the Saxenda schedule

FDA has approved liraglutide as Victoza and Saxenda, with generic versions tied to the Victoza application.

The approved products are prefilled pens, not powder vials, and their product labels are not interchangeable dosing instructions.

Common questions

How long do liraglutide side effects last, and do they go away?

The sources do not commit to a set number of days. What they describe is a pattern — reactions cluster after you start and after each increase, then ease while the dose is held steady. Any page quoting an exact number of days is quoting something the sources do not say.

What are the most common liraglutide side effects?

Nausea, diarrhea, constipation and vomiting — the table above has the rest, each with its frequency band and source.

What is the liraglutide boxed warning?

Liraglutide carries a boxed warning for risk of thyroid C-cell tumors — the most serious warning a label can carry. Liraglutide caused thyroid C-cell tumors in rats and mice. Whether it causes these tumors, including medullary thyroid carcinoma, in humans is unknown. The labels contraindicate use with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

Can the liraglutide dose be lowered if side effects are hard to tolerate?

That decision belongs to the prescribing clinician. The label sets a single dose rather than a ladder, so there is no step to hold at. Any change to it sits with the prescriber.

Does liraglutide cause hair loss?

Hair loss is not among the reactions listed on this page for liraglutide, because the FDA label cited here does not carry it. Anything missing from the tables is outside what can be sourced here rather than ruled out, and a symptom that worries you belongs with a clinician.

Is fatigue a listed liraglutide side effect?

No — the FDA label cited here does not list it. That describes what was reported, not proof that the symptom cannot happen.

Is constipation a listed liraglutide side effect?

Yes — it appears on this page among the reactions reported in the FDA label. It usually gets discussed separately from nausea, partly because anything reached for over the counter interacts with the rest of a medicine list.

What should someone do about a serious liraglutide reaction?

Contact a clinician promptly, and emergency services if symptoms are severe or getting worse quickly. The section above describes what those reactions actually look like, so they can be spotted early rather than explained away.

Do the frequencies on this page mean the chance it happens to one person?

No. These figures describe groups in a study. A band shows how often a reaction appeared under that trial’s conditions. It cannot predict what will happen to one person.

Related

The schedule these reactions were recorded against, the comparisons, and the sourcing rules behind every grade on this page.

The molecule behind Victoza and Saxenda

Published half-life: 13 hours.

What a studied liraglutide figure is, and what it is not

Published liraglutide dose information, not a personal schedule to follow.

What is documented about mixing liraglutide

Two co-administered drugs are written into this whole database, both on approved labels, with liraglutide as one example

Vial, water and dose for any peptide, with liraglutide as one example

U-100, U-50 and U-40 barrels each read differently, including liraglutide

The diarrhea question separate from liraglutide

Which sources name diarrhea, under what wording and at what frequency, beyond liraglutide.

Constipation weighed class-wide, including liraglutide

Named constipation entries, grouped figures and absences kept distinct, apart from liraglutide.

Which other pages list nausea besides liraglutide

One reaction, nausea, read down every page instead of out of liraglutide alone.

All the pages liraglutide is compared with

The spine every dosing, safety and calculator page reads from, including liraglutide

2primary sources, each with the day we read it — open the documents used on this page