Liraglutide Side Effects, From the Label Itself
The oldest drug in this class has the largest safety record behind it, and the highest reported nausea rate of any of them. It is also the one with published adolescent data, which reads differently from the adult figures.
- 39.3%Of adults reported nausea, against 13.8% on placebo
- 34.4%Of adolescents vomited, against 15.7% of adults on the same drug
- 9.8%Of adults stopped because of side effects, against 4.3% on placebo
- 3,384Adults in the safety population, the largest of any drug in this class
The short version
Nearly two in five adults reported nausea. That is the highest figure on any of the three labels we have read, and it sits alongside the smallest weight reduction — roughly 7.4% at 56 weeks. Liraglutide asks for more tolerance and returns less than the newer drugs.
That comparison needs a caveat, though, and it is a real one. This label draws on 3,384 adults — a bigger, longer-running record than the newer drugs have — and larger, more varied populations tend to report more. Some of the gap is a genuine difference in the drug; some is simply more evidence.
This page reports what the label reports. It is not a guide to managing side effects, and nothing here is a reason to change a prescribed medicine.
Every reaction reported in more than 2% of adults
Unlike the newer drugs, this label does not break the figures down by dose — everyone titrates toward the same maintenance amount, so the label reports a single treated column against placebo.
| Reaction | Placebo | Liraglutide |
|---|---|---|
| Nausea | 13.8% | 39.3% |
| Diarrhoea | 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 type 2 diabetes | 6.6% | 12.6% |
| Indigestion | 2.7% | 9.6% |
| Fatigue | 4.6% | 7.5% |
| Dizziness | 5.0% | 6.9% |
| Abdominal pain | 3.1% | 5.4% |
| Raised lipase | 2.2% | 5.3% |
| Upper abdominal pain | 2.7% | 5.1% |
| Gastroenteritis | 3.2% | 4.7% |
| Acid reflux | 1.7% | 4.7% |
| Abdominal bloating | 3.0% | 4.5% |
| Burping | 0.2% | 4.5% |
| Urinary tract infection | 3.1% | 4.3% |
| Flatulence | 2.5% | 4.0% |
| Insomnia | 1.7% | 2.4% |
| Dry mouth | 1.0% | 2.3% |
| Weakness | 0.8% | 2.1% |
| Anxiety | 1.6% | 2.0% |
Two rows repay a second look. Headache is 13.6% on the drug against 12.6% on placebo — a one-point gap, which is to say headache is close to background noise here despite appearing on the list. And injection site reactions run 13.9% against a 10.5% placebo rate, because the placebo group was injecting too. In both cases the number that matters is the gap, not the figure.
Nausea, vomiting and diarrhoea were also the three most common reasons people stopped taking it — nausea alone accounted for 2.9% of all participants leaving, against 0.2% on placebo.
The adolescent data, which is not the adult data
Liraglutide is approved for adolescents aged 12 and over who weigh more than 60 kg and have obesity. The label carries a separate safety table for them, from a 56-week trial of 125 young people against 126 on placebo — and it does not simply mirror the adult figures.
| Reaction | Placebo | Liraglutide | Adults on the drug |
|---|---|---|---|
| Nausea | 14.3% | 42.4% | 39.3% |
| Vomiting | 4.0% | 34.4% | 15.7% |
| Diarrhoea | 14.3% | 22.4% | 20.9% |
| Low blood sugar | 4.0% | 15.2% | — |
| Gastroenteritis | 4.8% | 12.8% | 4.7% |
| Dizziness | 3.2% | 10.4% | 6.9% |
Two figures worth pausing on
Vomiting was reported by 34.4% of adolescents against 15.7% of adults — more than twice the rate. And low blood sugar was reported by 15.2%, in a group the label notes did not have type 2 diabetes, against 4.0% on placebo. Anyone weighing this drug for a 12- to 17-year-old should be looking at this table rather than the adult one above it.
The adolescent trial is small — 125 young people on the drug — so individual percentages carry more uncertainty than the adult figures beside them. That is a reason to read them carefully, not a reason to discount them.
The serious warnings
- Thyroid C-cell tumours — the boxed warning, and the strongest version of it in this class. The label states that liraglutide causes these tumours in both rats and mice at clinically relevant exposures. Tirzepatide’s cites rats alone; orforglipron’s records none. Contraindicated with a personal or family history of medullary thyroid carcinoma, or MEN 2.
- Heart rate increase. A distinct warning on this label that the newer drugs in the class do not carry. Worth knowing about for anyone with a cardiac history.
- Suicidal behaviour and ideation. Carried here and on tirzepatide’s label; orforglipron’s has no equivalent entry. That is a difference between labels rather than a demonstrated difference in risk — a drug approved in 2026 has far less accumulated data behind it than one approved in 2010.
- Pancreatitis, gallbladder disease, severe gastrointestinal reactions and kidney injury from dehydration. The standard set across this class. The raised lipase in the table above is a pancreas-related marker, which is why pancreatitis is watched for.
- Low blood sugar, hypersensitivity reactions, and aspiration under anaesthesia. The hypoglycaemia risk rises sharply alongside insulin or a sulfonylurea, and the adolescent figures above show it is not confined to people with diabetes.
What this site will not tell you
- How to reduce or manage these reactions, or whether to change your dose. Both are conversations with a prescriber.
- Whether an adolescent should take it. The approval exists and the safety data is above; applying it to a particular young person is a clinical judgement.
- That liraglutide is definitively worse tolerated than the newer drugs. Its nausea figure is higher, but it comes from a larger and longer record, and no trial has compared them directly.
- Whether the generic behaves differently. A generic must be therapeutically equivalent to the product it references, so this label’s data is the relevant data.
Sources and method
- Every figure on this page. The approved prescribing information for Saxenda (liraglutide), NDA 206321, read from the FDA’s own document archive — the adult and adolescent adverse reaction tables, the discontinuation figures, and the warnings section.
- The safety populations. 3,384 adults against 1,941 on placebo, and separately 125 adolescents against 126 on placebo over 56 weeks. The adult table reports reactions over 2%; the adolescent table uses a 3% threshold, so the two are not directly comparable row for row.
- On comparing drugs. Labels use different thresholds and draw on populations of very different sizes. Where this page sets liraglutide beside another drug it says so explicitly, and it does not rank them on tolerability, because no head-to-head trial supports that.
- Method. Every percentage is reproduced with its placebo comparison. Where a reaction barely separates from placebo — headache here — that is stated rather than left for the reader to notice.
Liraglutide index → Tirzepatide side effects → Orforglipron side effects →
FDA label read 5 September 2026. We recheck this page whenever the label is revised.