Liraglutide vs semaglutide
Direct answer
What you need to know
Evidence strength: StrongThese two have been compared directly twice, and semaglutide won both times on the thing each trial set out to measure. At weight-management doses, STEP 8 randomised 338 adults for 68 weeks and found a mean weight change of −15.8% against −6.4%. At diabetes doses, SUSTAIN 10 found HbA1c falling 1.7% against 1.0%. What the two trials do not agree on is tolerability — and they point in opposite directions, which is the part that gets quoted selectively.
Key takeaways
- On weight, the margin is large and it comes from a real head-to-head: −15.8% vs −6.4% over 68 weeks.
- Both trials were funded by Novo Nordisk, which makes both drugs — unusually, there is no side for the funder to take.
- Tolerability has no single answer. Near-identical gastrointestinal rates at weight doses, more events with semaglutide at diabetes doses.
- The practical difference is the schedule: liraglutide is injected daily, semaglutide weekly.
Important limitation: Both head-to-head trials were open-label between the active arms, meaning participants knew which drug they were taking. That matters more for reported side effects and for stopping treatment than it does for weight on a scale.
Next action: If you are choosing between them, the deciding factor is usually coverage rather than trial results. Check what your plan covers before you rank the molecules, and see what each route actually costs.
Primary sources: JAMA (Rubino et al.), STEP 8, Diabetes & Metabolism (Capehorn et al.), SUSTAIN 10
General education, not medical advice. We do not publish dosing instructions — follow the label on your own prescription.
The two trials, side by side
Direct comparisons are rare in this class. Most “X vs Y” writing sets one trial’s headline figure beside another trial’s, which compares two study populations as much as two drugs. These two molecules are an exception: they have been randomised against each other twice, by the company that makes both of them.
| Trial | What was compared | Who, and for how long | What it found |
|---|---|---|---|
| STEP 8Phase 3b, randomised 3:1:3:1, open-label between the active arms | Semaglutide 2.4mg weekly vs liraglutide 3.0mg daily | 338 adults, 68 weeksAdults with overweight or obesity, without diabetes | Semaglutide −15.8% vs liraglutide −6.4% (difference −9.4 percentage points, 95% CI −12.0 to −6.8, P<0.001); pooled placebo −1.9%. Reaching 10% or more loss: 70.9% vs 25.6%. Reaching 20% or more: 38.5% vs 6.0%. Discontinuation for any reason 13.5% vs 27.6%, while gastrointestinal adverse events were reported by 84.1% and 82.7% respectively. |
| SUSTAIN 10Phase 3b, randomised 1:1, open-label | Semaglutide 1.0mg weekly vs liraglutide 1.2mg daily | 577 adults, 30 weeksAdults with type 2 diabetes and HbA1c 7.0–11.0% on one to three oral antidiabetic drugs | HbA1c fell 1.7% with semaglutide vs 1.0% with liraglutide (treatment difference −0.69%, 95% CI −0.82 to −0.56, P<0.0001). Body weight fell 5.8kg vs 1.9kg (difference −3.83kg, 95% CI −4.57 to −3.09, P<0.0001). Safety profiles were generally similar except for higher rates of gastrointestinal adverse events with semaglutide. |
One thing is worth saying about the funding before anything else. Both trials were paid for by Novo Nordisk, and Novo Nordisk makes both molecules — liraglutide as Saxenda and Victoza, semaglutide as Wegovy, Ozempic and the tablets. That is a different situation from the usual manufacturer-funded comparison, where one drug belongs to the sponsor and the other does not. Here the sponsor had no side to take, which is a genuine reason to weigh these results more heavily than a trial run against a competitor’s product.
Where the two trials disagree
Almost exactly the same proportion of people reported gastrointestinal side effects on each drug — and twice as many stopped taking liraglutide.
The weight and blood-sugar results point the same way in both trials. Tolerability does not, and this is the part worth reading carefully, because it is where a single-trial summary will mislead you.
In STEP 8, at the weight-management doses, gastrointestinal adverse events were reported by 84.1% of the semaglutide group and 82.7% of the liraglutide group. On that measure the two drugs are indistinguishable. Yet 27.6% of the liraglutide group discontinued treatment for any reason against 13.5% on semaglutide — more than double.
The trial reports both numbers and does not explain the gap between them, so neither will we. What can be said is that “how many people reported a side effect” and “how many people stopped” are different questions, and a drug can score well on the first while losing people anyway. Whether that reflects severity, the daily injection schedule, the trial’s rule that people unable to tolerate liraglutide discontinued rather than dropping to a lower dose, or something else, is not something the published result settles.
Then SUSTAIN 10, at the lower diabetes doses, found the opposite direction: safety profiles generally similar except for higher rates of gastrointestinal adverse events with semaglutide. So the answer to “which is gentler” depends on which pair of doses is being compared, and there is no version of that question that both trials answer the same way.
Daily against weekly, which is the difference you will actually feel
Every liraglutide product is a daily injection. Every semaglutide injection is weekly, and semaglutide is additionally the only one of the two available as a tablet. Over a year that is roughly 365 injections against 52.
Which is better is genuinely personal. A weekly injection is fewer events to remember and fewer needles; a daily one keeps each dose smaller and, for some people, is easier to build into a routine precisely because it happens every day. If injections themselves are the obstacle, the relevant comparison is not this one — it is the tablets, all of which are semaglutide or orforglipron, because liraglutide has no oral form.
Which brand is which
Most confusion about these two molecules is really confusion about five brand names. Each molecule is sold under one name for diabetes and another for weight, at different doses, and the names give no clue which is which.
| Brand | Molecule | Approved for | How it is taken |
|---|---|---|---|
| Victoza | liraglutide | type 2 diabetes | daily injection |
| Saxenda | liraglutide | chronic weight management | daily injection |
| Wegovy | semaglutide | chronic weight management | weekly injection or daily tablet |
| Ozempic | semaglutide | type 2 diabetes | weekly injection |
| Rybelsus | semaglutide | type 2 diabetes | daily tablet |
What each costs, and the comparison we cannot make
Neither liraglutide product publishes a manufacturer self-pay price. Semaglutide does — several, across its tablet and pen forms — so a cash-paying reader can price one molecule from published figures and not the other. That is not a finding about which is cheaper; it is the reason no honest cash comparison appears on this page. If you have insurance, the question that decides your cost is which of the two your plan covers, and that is answerable in one phone call in a way no page can be. Our cost comparison prices every route we can source, and states the gaps as gaps.
Questions people ask
Is semaglutide better than liraglutide?
For weight loss, the head-to-head trial says yes and the margin is large. STEP 8 randomised 338 adults with overweight or obesity to weekly semaglutide 2.4 mg or daily liraglutide 3.0 mg for 68 weeks: mean weight change was −15.8% against −6.4%, a difference of 9.4 percentage points. Nearly three times as many people reached 10% weight loss on semaglutide, and six times as many reached 20%. That is a direct comparison rather than an inference across separate trials, which is rare in this class.
Which one has worse side effects?
The two head-to-head trials disagree, and which one applies depends on the doses. At weight-management doses in STEP 8, gastrointestinal adverse events were reported at almost identical rates — 84.1% on semaglutide and 82.7% on liraglutide — yet more than twice as many people stopped liraglutide (27.6% against 13.5%). At the lower diabetes doses in SUSTAIN 10, the finding ran the other way: gastrointestinal events were more frequent with semaglutide. Anyone quoting one of those trials as the answer is quoting half the evidence.
What is the difference between Saxenda and Wegovy?
Saxenda is liraglutide and Wegovy is semaglutide — different molecules from the same manufacturer, both approved for chronic weight management. The practical difference is the schedule: Saxenda is a daily injection, Wegovy a weekly one, and Wegovy is also available as a daily tablet. In the head-to-head trial at these doses, semaglutide produced substantially more weight loss.
What is the difference between Victoza and Ozempic?
The same molecules in their type 2 diabetes versions: Victoza is liraglutide, injected daily; Ozempic is semaglutide, injected weekly. Both also carry an indication to reduce the risk of major adverse cardiovascular events. SUSTAIN 10 compared them at commonly prescribed doses and found semaglutide reduced HbA1c by 1.7% against 1.0%, and body weight by 5.8 kg against 1.9 kg.
Is liraglutide cheaper than semaglutide?
We cannot tell you, because Novo Nordisk publishes no self-pay price for either liraglutide product. Semaglutide has published direct-purchase prices; liraglutide does not, so a cash-paying comparison cannot be made from published figures. What you pay for liraglutide depends on your insurance and your pharmacy, and the only way to find out is to ask both.
Why would anyone still be prescribed liraglutide?
Several reasons that have nothing to do with which trial won. Coverage is the commonest — a plan may cover one and not the other. Liraglutide has been on the market far longer, so there is more experience with it. Saxenda is approved from age 12 in adolescents meeting its criteria. And a daily injection suits some people better than a weekly one, particularly anyone who prefers a smaller dose more often. This is a prescriber's decision informed by your circumstances, not a league table.
When to seek medical care
Both molecules carry the same boxed warning about thyroid C-cell tumours seen in rodents, and the same contraindications in people with a personal or family history of medullary thyroid carcinoma or MEN 2. Severe or persistent abdominal pain after starting either drug needs medical attention rather than a web page.This page is general education, not medical advice. Talk to your own healthcare provider about your situation before starting, stopping, or changing any medication.
Sources
Each source below supports specific statements on this page. We cite the strongest available authority and verify against the current version before publishing.
- Effect of Weekly Subcutaneous Semaglutide vs Daily Liraglutide on Body Weight in Adults With Overweight or Obesity Without Diabetes: The STEP 8 Randomized Clinical TrialJAMA (Rubino et al.), STEP 8Supports: The randomised head-to-head at weight-management doses: 338 adults over 68 weeks, and the source for every weight figure and both discontinuation rates on this page.
- Efficacy and safety of once-weekly semaglutide 1.0mg vs once-daily liraglutide 1.2mg as add-on to 1-3 oral antidiabetic drugs in subjects with type 2 diabetes (SUSTAIN 10)Diabetes & Metabolism (Capehorn et al.), SUSTAIN 10Supports: The randomised head-to-head at diabetes doses: 577 adults over 30 weeks, and the source for the HbA1c figures and the opposing tolerability finding.
- FDA-approved prescribing information (drug labels)DailyMed, U.S. National Library of MedicineSupports: Approved indications, dosing frequency and administration for Saxenda, Victoza, Wegovy, Ozempic and Rybelsus, read from each product's current label.
- Drug approvals, labeling and safety communicationsU.S. Food & Drug AdministrationSupports: Approval status, prescription-only classification, and the boxed warning carried by both molecules.