The numbers depend on what is counted
The US label gives a single adult figure for reactions such as rash and redness. [1] The EU summary reports all injection-site adverse events and, separately, those that may be immune-related. [3] Canada counts every site event that happened during treatment, including bruising and pain, whether or not the medicine caused it. [4] The same trials therefore yield 0.5%, 0.7%, 1.7% or 1.9%.
| Document, population and pool | Trulicity® | Comparison |
|---|---|---|
| US label, adults, placebo-controlled studies [1] | 0.5% | Placebo 0.0% |
| US label, children 10 and older [1] | 0.75 mg: 3.9% (2); 1.5 mg: 3.8% (2) | Placebo 2.0% (1) |
| EU SmPC, adults, all site adverse events [3] | 1.9%; possibly immune-related 0.7% (“uncommon”) | — |
| EU SmPC, paediatric study [3] | “Common”; all mild to moderate | Placebo 2% |
| Canada, placebo-controlled trials [4] | 38 people (1.7%); 2 stopped treatment | Placebo 6 (0.9%) |
| Canada, studies up to 104 weeks [4] | 1.9%; immune-type 0.5% (0.75 mg) and 0.7% (1.5 mg); 1 stopped | — |
Bruising, pain and redness in the Canadian detail
Canada is the only document that names the individual events. In its placebo-controlled trials, a bruise at the injection site was the most frequent entry in both groups, 17 people on Trulicity® (0.8%) and 3 on placebo (0.4%). Pain (6 people, 0.3%) and redness (4 people, 0.2%) were reported only on Trulicity®. [4] In studies of up to 104 weeks, bruising again led, at 0.9% on 0.75 mg and 0.6% on 1.5 mg. [4]
Those counts are small, and very few people stopped treatment because of a site reaction. [4] The US label does not describe how long reactions lasted. [1]
Children and teenagers
In the US label, the safety profile in young people aged 10 and over matched adults with one exception: injection-site reactions, which section 8.4 says were more frequent than in adults. [1] Behind the percentages are five young people in total, two in each Trulicity® group and one on placebo, so a single case shifts the figure by about two points. [1] Europe adds that every paediatric event was mild to moderate. [3]
Antibodies against dulaglutide appeared in 4% of young people on Trulicity® during the first 26 weeks, and the US label says their effect in children is unknown because so few developed them. [1] Europe reports 4.0% on dulaglutide against 2.1% on placebo. [3] Health Canada has not authorised Trulicity® for anyone under 18. [4]
Where antibodies come in
Across the adult trials, 64 of 3,907 people on Trulicity® (1.6%) developed antibodies to dulaglutide, and the US label found no clinically significant effect on safety or effectiveness. [1] The Canadian monograph adds one link: immune-type site reactions occurred in 2 of those 64 people (3.1%) against 18 of 3,843 without antibodies (0.5%). [4] Both Europe and Canada note that no one with antibodies had a body-wide allergic reaction. [3][4]
What studies across the drug class show
A 2026 meta-analysis pooled 14 randomised trials with 4,861 participants and 396 site reactions, and found a risk ratio of 3.55 (95% CI 2.35 to 5.36) for GLP-1 medicines against comparators. [5] In the same paper, an analysis of US voluntary reports flagged injection-site bleeding as disproportionately reported for dulaglutide, a pattern that fits Canada’s finding that bruising was the leading local event. [4][5] Voluntary reports show what people report more often, not how frequently it happens or whether the medicine caused it.
A 2020 narrative review of 30 phase 3 trials of once-weekly GLP-1 medicines, dulaglutide included, judged the risk of site reactions generally low. [6] The two findings are compatible: a reaction can be several times more likely than with a comparator and still affect only a few people in a hundred.
Local, infected or allergic?
- Local: a little redness, a small bruise or some soreness confined to the spot. MedlinePlus expects some soreness after an injection under the skin. [7] Europe describes the possibly immune-related reactions as usually mild. [3]
- Infected: redness that keeps spreading, warmth, swelling, red streaks or fever. MedlinePlus lists these as signs of infection to report, and cellulitis can grow quickly within a day. [7][8]
- Allergic: hives or itching away from the injection site, a swollen face, lips, tongue or throat, difficulty breathing or swallowing, a very fast heartbeat or fainting. The guide asks you to stop Trulicity® and get medical help right away. [2] Trulicity® should not be used after a serious allergic reaction to dulaglutide or any ingredient. [1]
- Ingredient note: the pens contain polysorbate 80, which Europe says may cause allergic reactions, so known allergies are worth mentioning before starting. [3]
Injection technique in the official documents
- Places: the abdomen, thigh or upper arm, always under the skin and never into a muscle or vein. [1][2] The EU and Canadian pen instructions keep the upper arm for injections given by someone else. [3][4]
- Rotation: change the spot every week; you may stay in the same body area as long as you pick a different site within it. [1][3]
- With insulin: two separate injections, never mixed; the same body area is acceptable, but not right next to each other. [1][2]
- Before injecting: the solution should be clear and colourless, and a pen with particles or discolouration should not be used. [1] MedlinePlus adds that the chosen spot should be free of redness, swelling, scarring and bruising. [7]
- Training: the US label asks prescribers to show patients and caregivers how to inject before the first dose. [1]
Soothing a sore spot
None of the Trulicity® documents recommends ice, creams or other treatments for a local reaction, so there is no product-specific advice to follow. [1][3][4] The one comfort step they mention is Canada’s: let the pen warm to room temperature before injecting, never by microwave or hot water. [4] The US label allows a pen to stay at room temperature, up to 30°C (86°F), for a total of 14 days if needed. [1]
For itchy welts, MedlinePlus suggests avoiding hot baths and tight clothing, and says a provider may suggest an antihistamine; ask a pharmacist before using one. [9] MedlinePlus’s dulaglutide entry treats hives, rash or itching as a reason to stop and contact your doctor, so do not assume a spreading itch is only local. [10]
Trulicity® is a registered trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.
When to get help
The signs and contact information below come from this article’s sourced guidance.
Emergency
- Swelling of the face, lips, tongue or throat, wheezing, trouble breathing or swallowing, or fainting
Contact: Stop Trulicity® and call emergency services (911 / 112)
- Hives, rash or itching that spreads beyond the injection site
Contact: Stop Trulicity® and contact your doctor right away