Liraglutide for weight loss is a daily injection, sold as Saxenda at a 3 mg dose. If you are weighing it up, the side effects are the part you will feel first. This page walks through what the trials recorded, from the common to the rare.
The numbers come from placebo-controlled trials. That matters, because people on a dummy shot also report nausea and headaches. What counts is the gap.
What you are most likely to feel
The label pools five double-blind trials with 3,384 adults on Saxenda [1]. They stayed on it for 46 weeks on average. The table shows reactions seen in at least 2% of them and more often than on placebo.
| Side effect | Placebo | Saxenda |
|---|---|---|
| Nausea | 13.8% | 39.3% |
| Diarrhea | 9.9% | 20.9% |
| Constipation | 8.5% | 19.4% |
| Vomiting | 3.9% | 15.7% |
| Injection-site reaction | 10.5% | 13.9% |
| Headache | 12.6% | 13.6% |
| Low blood sugar, in people with type 2 diabetes | 6.6% | 12.6% |
| Indigestion (dyspepsia) | 2.7% | 9.6% |
| Fatigue | 4.6% | 7.5% |
| Dizziness | 5% | 6.9% |
| Raised lipase (a pancreas enzyme) | 2.2% | 5.3% |
| Burping | 0.2% | 4.5% |
| Trouble sleeping | 1.7% | 2.4% |
| Dry mouth | 1% | 2.3% |
When nausea shows up, and whether it fades
Saxenda starts low and climbs each week until you reach 3 mg. That climb is when stomach effects tend to appear.
One early trial tracked this closely in 564 adults with obesity and no diabetes. [3] Most nausea and vomiting came in weeks 1 to 6, during the dose steps. On 3 mg, 48% reported some nausea and 13% some vomiting. Only 4 of the 93 on that dose withdrew.
The label adds that the share of people with nausea fell as treatment continued [1]. Stomach effects led 6.2% to stop Saxenda, against 0.8% on placebo.
Tiredness, dizziness and a changed sense of taste followed a similar pattern. The label says they were mainly reported in the first 12 weeks, often alongside nausea or diarrhea.
68%
of adults on Saxenda had a stomach or bowel effect, against 39% on placebo
Saxenda label
9.8%
stopped early because of side effects, against 4.3% on placebo
Saxenda label
Weeks 1–6
when most nausea and vomiting occurred, during the dose steps
Lean 2014
What a daily injection adds
A daily shot means 7 injections a week instead of 1. Injection-site reactions were reported by 13.9% on Saxenda and 10.5% on placebo [1]. Redness, itching and rash at the site were the usual forms.
A small number of people make antibodies to liraglutide. That happened in 2.8% of adults tested. The label says antibodies may go with more injection-site reactions, which were usually mild.
Liraglutide is taken daily, and semaglutide once a week. How liraglutide stacks up against the weekly shot is covered in liraglutide vs semaglutide.
The rarer side effects to know by name
These events are uncommon, but each has its own warning in the label. [1] Knowing the symptoms helps you spot them early.
| Event | Saxenda | Placebo |
|---|---|---|
| Gallstones (cholelithiasis) | 2.2% | 0.8% |
| Gallbladder inflammation (cholecystitis) | 0.8% | 0.4% |
| Acute pancreatitis, confirmed by adjudication | 0.3% | 0.1% |
| Severe stomach or bowel reactions | 4.8% | 1.4% |
| Low blood pressure reactions | 1.1% | 0.5% |
| Heart conduction changes on ECG | 0.3% | none |
Most people on Saxenda who had gallstones or gallbladder inflammation needed their gallbladder removed [1]. The label notes that fast weight loss raises gallstone risk. Even so, the risk stayed higher on Saxenda after accounting for weight lost.
Pancreatitis can show up as severe belly pain that may spread to your back. The label says to stop the drug if it is suspected. A few cases in the trials appeared weeks to months after the last dose.
Your heart rate may run a little faster. Resting heart rate rose by a mean of 2 to 3 beats per minute over placebo. A rise of more than 10 beats at two visits in a row happened in 34%, against 19%.
If you take a sulfonylurea for diabetes, low blood sugar is the one to watch. In that group, glucose below 54 mg/dL occurred in 28.2% on Saxenda and 12.7% on placebo.
Cancer cases the label reports
The label lists a few cancer counts from the trials [1]. Breast cancer was confirmed in 0.7% of women on Saxenda and 0.2% on placebo. The label says there were too few cases to tell whether the drug was involved.
Papillary thyroid cancer was confirmed in 8 people on Saxenda and none on placebo. Four of those tumors were under 1 cm. Four were found after thyroid surgery prompted by findings from before treatment began.
What happened over one and three years
The largest weight trial, SCALE Obesity and Prediabetes, gave 3,731 adults without diabetes liraglutide 3 mg or placebo for 56 weeks. [2] Nausea and diarrhea, mostly mild or moderate, were the most frequent complaints. Serious events occurred in 6.2% on liraglutide and 5.0% on placebo.
People with prediabetes stayed on for up to 160 weeks [4]. Serious adverse events were reported by 15% on liraglutide and 13% on placebo. Many dropped out along the way: 47% on liraglutide and 55% on placebo.
Reports since approval
Postmarketing reports cannot tell you how often something happens [1]. They include severe pancreatitis, bowel obstruction, dehydration from vomiting or diarrhea, liver enzyme rises and allergic reactions. Medullary thyroid carcinoma is on the list too.
If you have surgery planned, tell your care team you take it. Aspiration under anesthesia has been reported with drugs in this class. The label's change log shows the suicidal thoughts warning was removed in February 2026.
What this means for you
Expect the first six weeks to be the hardest on your stomach. For most people the effects were mild and eased with time. The rarer problems are worth knowing by their symptoms, so you can call your prescriber quickly.
The weekly drug's own side-effect record is in semaglutide side effects.
For the wider picture, read peptides for weight loss. Prescribers for the weekly options are compared on the weight-loss peptides board, and more choices sit on the weight goal page.