Site reactions in the product documents
The US label groups site reactions under one heading in its adult table and names the most frequent kinds in a footnote; the Canadian monograph lists them separately from the same trials. [1][3] The EU puts injection site reactions in its common class and lists cutaneous amyloidosis with an unknown frequency. [2]
| Document and term | Saxenda® | Placebo | Note |
|---|---|---|---|
| US label, Table 2, all site reactions, adults [1] | 13.9% | 10.5% | Redness, itching, rash each 1–2.5% |
| Canadian monograph, Table 3, site erythema [3] | 86 of 3,384 (2.5%) | 4 of 1,941 (0.2%) | Redness |
| Canadian monograph, Table 3, site reactions / pruritus / rash [3] | 2.5% / 1.3% / 1.1% | 0.6% / 0.2% / 0.1% | Separate preferred terms |
| US label, Table 3, site pain, ages 12–17 [1] | 3.2% | 3.2% | No difference from placebo |
| EU SmPC, Table 4 [2] | Common; amyloidosis not known | — | Usually mild and transient |
Reading the figures
The headline US figure includes reactions that people on placebo had too, because the placebo was injected in the same way. The difference, about three people in every hundred, is the part linked to liraglutide itself. [1] Canada’s split by type shows the excess is mostly redness, itching and small rashes. [3]
The EU and Canadian documents describe these reactions as usually mild and short-lived, with most disappearing while people kept using the medicine. [2][3] The EU leaflet gives everyday examples: bruising, pain, irritation, itching and rash. [2]
In the teenage trial, site pain was reported equally often with Saxenda® and placebo, which suggests the needle rather than the medicine explains most of it in that group. [1]
Antibodies, allergy and lumps
Antibodies to liraglutide were found in 42 of 1,505 adults (2.8%) tested after starting Saxenda®, and 1.2% had antibodies that blocked liraglutide in a laboratory test. The label says antibodies may be associated with more injection site reactions and reports of low blood sugar, and that these events were usually mild and resolved during treatment. [1] In teenagers, 12% developed antibodies, none of them neutralising. [1]
Hives were reported by 0.7% on Saxenda® and 0.5% on placebo. [1] Serious allergic reactions, including anaphylaxis and angioedema, have been reported with liraglutide, and the EU lists anaphylaxis as rare. [1][2] A 2026 analysis of EU spontaneous reports found hypersensitivity in 0.73% and angioedema in 0.19% of liraglutide reports; reports of this kind cannot show how often reactions happen or prove cause. [8]
Cutaneous amyloidosis is a build-up of a protein called amyloid at injection sites, which can form lumps. It has been reported after approval, and the frequency is unknown. [1][2][3] The Canadian leaflet notes the medicine may not work as well if injected into a lumpy area. [3]
Other reasons a site can react
- Injecting into skin that is already red, swollen, scarred or bruised; MedlinePlus says injection sites should be healthy. [4]
- Using the same spot repeatedly instead of moving between sites. [1][4]
- Reusing a needle: the Instructions for Use call for a new needle every time, partly to avoid blocked needles and contamination. [1]
- Infection, which brings spreading redness, warmth, tenderness, swelling and sometimes fever. [5]
- Allergy to something else, as hives are often caused by a drug or food, and also by infections or stress. [6]
Injection habits the documents describe
The Saxenda® Instructions for Use describe wiping the site with an alcohol swab and letting it dry, inserting the needle as you were shown, holding the dose button until the counter shows 0, keeping the needle in while counting slowly to six, and pressing lightly with a cotton ball or gauze if blood appears, without rubbing. A new needle is used for each injection and the pen is never shared. [1]
Saxenda® can go into the abdomen, thigh or upper arm. The US label asks you to rotate sites within the same region, the Medication Guide asks you not to use the same site for each injection, and changing site or time needs no dose change. [1] The EU leaflet asks you to change the place you inject each day to reduce the risk of lumps. [2]
MedlinePlus adds that hands should be washed first, that the chosen site should be free of redness, swelling, scarring or bruising, and that some soreness at the site is expected. [4]
Saxenda® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| A swollen face, lips, tongue or throat; difficulty breathing or swallowing; fainting or a racing heart | Stop Saxenda® and call your emergency number | Emergency | Medication Guide [1]; MedlinePlus [7] |
| Severe rash or severe itching | Stop Saxenda® and get medical help right away | Emergency | Medication Guide [1] |
| Redness that keeps spreading, warm skin, red streaks, fever or chills | Your provider right away | Today | MedlinePlus [4][5] |
| Firm lumps under the skin where you usually inject | Your prescriber or nurse | At your next appointment | Canadian leaflet [3]; Prescribing Information [1] |
| Site reactions that keep returning after several weeks | Your prescriber | At your next appointment | Medication Guide [1] |
