Dulaglutide is one of the original once-weekly GLP-1 receptor agonists, and it remains one of the most widely prescribed diabetes medications in the world under its brand name, Trulicity, even as newer drugs like semaglutide and tirzepatide have captured more headlines.
What It Is
Dulaglutide is a GLP-1 receptor agonist, a class of drugs that mimic the natural hormone GLP-1 to stimulate insulin release, slow digestion, and reduce appetite. What sets dulaglutide apart structurally is its design: a modified GLP-1 peptide fused to a fragment of a human antibody, known as an Fc region. This Fc-fusion approach dramatically slows the drug's breakdown in the body, which is what allows once-weekly injections instead of the daily dosing required by earlier GLP-1 drugs like exenatide.
Regulatory Status
Dulaglutide was FDA-approved in 2014 under the brand name Trulicity for the treatment of type 2 diabetes, developed and marketed by Eli Lilly. Its approved uses have since expanded to include reducing the risk of major cardiovascular events in adults with type 2 diabetes who either have known heart disease or multiple cardiovascular risk factors. Trulicity is not FDA-approved specifically for weight loss the way Wegovy (semaglutide) or Zepbound (tirzepatide) are, although weight loss is a commonly observed effect in people taking it for diabetes.
What the Research Shows
Dulaglutide's approval rested on a substantial clinical trial program, including the REWIND cardiovascular outcomes trial, which enrolled more than 9,000 participants and found that dulaglutide reduced the risk of major cardiovascular events compared with placebo in adults with type 2 diabetes. That trial is notable in the GLP-1 literature because it included a broader mix of participants, including many without existing cardiovascular disease, than some earlier cardiovascular outcome trials in this drug class.
How It Compares to Newer GLP-1 Drugs
Head-to-head trials have generally found that dulaglutide produces less weight loss and somewhat smaller blood sugar improvements than newer once-weekly options like semaglutide, and considerably less than the dual GLP-1/GIP agonist tirzepatide. That doesn't make dulaglutide obsolete: it has a long real-world safety track record and remains a reasonable option for patients and prescribers depending on individual response, insurance coverage, and side-effect tolerance.
Safety Considerations
Dulaglutide's most common side effects are gastrointestinal, including nausea, diarrhea, vomiting, and decreased appetite, similar to other drugs in its class. Like other GLP-1 receptor agonists, it carries a boxed warning about thyroid C-cell tumors observed in rodent studies, and it is contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. Anyone considering dulaglutide, or already prescribed it, should discuss their personal risk factors and any side effects with their doctor rather than adjusting or stopping treatment on their own.
The Bottom Line
Dulaglutide was a meaningful step in making GLP-1 therapy practical for daily life, cutting dosing frequency from daily to weekly years before semaglutide and tirzepatide became household names. It remains a thoroughly studied, FDA-approved option, even as newer drugs with stronger weight-loss data have taken more of the spotlight.