How often reactions happened
The US label reports injection site reactions, such as a rash or redness, in about 2% of adults treated with Victoza® in five double-blind glycemic control trials lasting at least 26 weeks, with fewer than 0.2% stopping because of them. [1] The European summary gives the same figure, places these reactions in its common class and describes them as usually mild. [2] The European leaflet lists the forms they take: bruising, pain, irritation, itching and rash. [2]
The Canadian monograph adds detail. It says bruising and pain were the most frequent forms and reports event rates by dose. [3] Placebo injections also produced reactions, which shows how much of this comes from injecting itself rather than from liraglutide. [3]
| Measure | Victoza® | Comparison |
|---|---|---|
| Injection site reactions, adult trials of 26 weeks or more [1] | About 2% | Not reported |
| Stopped because of injection site reactions [1] | Under 0.2% | Not reported |
| Injection site events per 1,000 years of exposure [3] | 0.6 mg 18.1; 1.2 mg 27.6; 1.8 mg 37.6 | Placebo 34.0; active comparator 14.9 |
| Trial 1860, injection site hematoma [3] | 1.2 mg 2.3%; 1.8 mg 2.8% | Sitagliptin tablets 0.0% |
| Trial 1842, injection site hematoma [3] | 1.9%; 2.5% with insulin detemir added | No placebo arm |
| Immune-related events such as hives, adult trials [1] | 0.8% | 0.4% |
Cutaneous amyloidosis: why rotation is in the label
Section 2.3 of the US label asks you to rotate injection sites within the same region to reduce the risk of cutaneous amyloidosis, and the condition appears in its list of reports received after approval. [1] The European summary gives the same reason for rotation and rates the frequency as not known. [2] Its leaflet explains that lumps under the skin may be caused by a build-up of a protein called amyloid. [2]
The Canadian patient information adds the practical consequence: Victoza® may not work very well if you inject into a lumpy area, so the site should change with each injection. [3] The European leaflet also asks you to change the place where you inject each day to reduce the risk of developing lumps. [2]
Where Victoza® goes and why it can move
Victoza® goes under the skin in one of three areas, the abdomen, thigh or upper arm, at any time of day and without regard to meals. [1] The US label says no dose adjustment is needed if you change the site or the timing. [1] In pharmacology studies the total exposure from the thigh was 22% lower than from the abdomen, but exposure across the three sites was considered comparable. [1] The Instructions for Use say the upper arm should be used only when a caregiver gives the injection. [1]
If you also use insulin, the label says the two must be separate injections and never mixed. They can go into the same body region, but not right next to each other. [1]
What research adds
A 2026 meta-analysis pooled 14 randomised trials that reported injection site reactions, covering 4,861 patients. Reactions were about 3.5 times as likely with GLP-1 medicines as with comparators, while wider skin reactions were infrequent and not significantly raised. [4] The same paper searched the US adverse event reporting system and found disproportionate reporting of injection site bleeding for exenatide and dulaglutide; liraglutide was not singled out. [4] Spontaneous reports cannot show how often something happens or prove cause.
Why it might happen
Label-supported: a needle and a daily injection can bruise or irritate the skin, which is why placebo injections produced reactions too. [3] Repeated injections into one spot can lead to amyloid deposits. [1][2]
Immune response, measured but not linked to reactions: about 9% of adults on Victoza® developed antibodies to liraglutide in trials, but those with antibodies were not more likely to have immune-related events such as hives, and the antibodies had no identified effect on how well Victoza® worked. [1] Fewer than 0.2% of people stopped because of injection site reactions, and Canada says none of them tested positive for antibodies. [3]
Allergy is a different problem
A sore or bruised spot is local. A serious allergic reaction is not. The US label reports anaphylaxis and angioedema after approval, and Victoza® must not be used by anyone who has had a serious allergic reaction to liraglutide or its ingredients. [1] The Medication Guide lists swelling of the face, lips, tongue or throat, fainting or dizziness, trouble breathing or swallowing, a very rapid heartbeat and a severe rash or itching, and asks you to stop Victoza® and get medical help right away. [1] Europe rates anaphylactic reactions as rare and hives and itching as uncommon. [2]
Other causes of a red spot exist too. MedlinePlus says some soreness is expected after a shot under the skin, but redness, swelling, red streaks and fever can point to infection. [5]
Pen and needle habits from the instructions
- Check the solution before each injection: it should be clear, colourless and free of particles. [1]
- Clean the chosen spot with an alcohol swab, then wait until the skin is dry. [1]
- Hold the dose button down and keep the needle under the skin for a full count of 6 seconds. [1]
- If blood appears afterwards, press lightly with a cotton ball or gauze, but do not rub. [1]
- Use a new needle each time, remove it after the injection and store the pen without a needle attached. [1]
- Never share a Victoza® pen, even with a new needle, because of the risk of passing on blood-borne infections. [1]
- Choose a healthy-looking site, free of redness, swelling, scarring or bruising, according to MedlinePlus. [5]
Victoza® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk A/S.
When to get help
The signs and contact information below come from this article’s sourced guidance.
Emergency
- A swollen face, lips, tongue or throat, difficulty breathing or swallowing, fainting or a racing heart
Contact: Stop Victoza® and call emergency services
Medication Guide [1]
- Severe rash or itching spreading beyond the injection site
Contact: Stop Victoza® and get medical help right away
Medication Guide [1]
Today
- Redness, swelling, red streaks or fever around an injection site
Contact: Contact your provider
MedlinePlus [5]