Dulaglutide vs semaglutide: how do they compare for weight loss?

Step 1 — understand the licensing gap before comparing the medicines

Both dulaglutide and semaglutide work by activating GLP-1 receptors in the gut and brain, slowing gastric emptying and reducing appetite. The mechanism is similar enough that the two are often bracketed together in conversation, and if you want a thorough breakdown, our page on the difference between dulaglutide and semaglutide goes into considerably more depth. The practical difference, though, is significant: the NHS medicines page for semaglutide covers its weight-management licence under Wegovy, while dulaglutide (Trulicity) carries no such authorisation from the MHRA. Prescribing it for weight loss in the UK would be off-label, meaning no manufacturer data submitted for that purpose, no regulatory weight-management approval and no licensed patient information leaflet covering that use.

That licensing distinction matters practically. A regulated UK pharmacy can only dispense a medicine for weight management when a prescriber is working within its licensed indication. Semaglutide as Wegovy is that licensed option. Dulaglutide is not. If you have come across dulaglutide being offered or discussed for weight loss, it is worth checking the GPhC register at pharmacyregulation.org/registers to confirm whether the source is a registered pharmacy before taking any step further.

Step 2, look at what the clinical evidence actually shows for each

Dulaglutide has solid trial evidence in type 2 diabetes, where head-to-head studies show meaningful HbA1c reductions and modest weight effects. However, those weight effects were secondary endpoints in diabetes trials, not the primary outcome in dedicated obesity studies. The doses used were also lower than what obesity trials typically test.

Semaglutide has a dedicated body of weight-management evidence. The STEP 1 trial (68 weeks, adults with obesity, no diabetes) recorded an average body-weight reduction of around 15% at the 2.4mg weekly dose, compared with placebo, published in the New England Journal of Medicine. The higher 7.2mg dose, approved by the MHRA in April 2026, showed around 20.7% average weight reduction over 72 weeks in trials, narrowing the gap with the dual-agonist tirzepatide. NICE has recommended Wegovy for eligible adults under technology appraisal TA875, which also sets the NHS access conditions.

The table below sets out the key comparison points factually.

Step 3, consider what the NHS and private routes look like for semaglutide

Because dulaglutide has no weight-management licence, there is no NHS or private weight-loss pathway built around it. The options that actually exist are built around semaglutide (Wegovy) and tirzepatide (Mounjaro). People sometimes ask how these options relate to each other, and our guide on semaglutide vs Wegovy explains the relationship between the molecule and the branded product clearly. On the NHS, Wegovy is available through specialist weight management services under TA875, though waiting lists in many areas are long. The NHS England guidance on weight-management injections sets out the eligibility criteria and the wraparound diet and activity support the NHS requires alongside treatment.

Private prescription is the faster route for people who meet the licensed criteria but are not yet eligible for the NHS pathway, or who do not want to wait. At nume, sorry, at nume, a GPhC-registered prescriber reads every consultation personally; no algorithm makes the decision. The free consultation is the starting point: eligibility is confirmed during that review, not assumed in advance. A useful one-minute check before starting: pull up the GPhC register, search the pharmacy's name, and confirm the premises registration is current. Ours is 9012878, verifiable directly at pharmacyregulation.org.

Step 4, how to make the right decision (it is a clinical one)

If you have type 2 diabetes and your GP has mentioned dulaglutide, that conversation belongs with your diabetes team; it is a legitimate medicine for that indication. If your goal is weight management, dulaglutide is not a licensed option in the UK, and a prescriber working within the law cannot issue it for that purpose through a regulated pharmacy. The relevant medicines are semaglutide as Wegovy and tirzepatide as Mounjaro. You can read about how semaglutide compares with other GLP-1 options or explore the full range of weight-loss treatments we offer at nume.

Which of the licensed options suits you depends on your medical history, current medications, BMI, any weight-related conditions and your own preferences around injection versus tablet. Common side effects for semaglutide are gastrointestinal: nausea, loose stools, constipation and indigestion are the ones most frequently reported, usually most noticeable in the early weeks. That profile is similar across the GLP-1 class, and our pages covering GLP-1 vs semaglutide and semaglutide vs Ozempic give more context on how these medicines relate to one another. No prescriber can tell you which medicine is right before reviewing your full picture. That review, with a real clinician, is where this decision gets made properly. Check your eligibility with our team.