Question 1

Liraglutide vs semaglutide: what is the difference?

Accepted Answer

They are siblings rather than rivals, made by the same line of work on the same gut hormone. A 2019 history of both says that rational design has led to the development of two long-acting GLP-1 analogs, liraglutide and semaglutide. Long-acting here means each was built to stay in the blood far longer than the natural hormone does, which is the problem the whole design effort set out to solve. The difference you notice is the calendar. In the one trial that gave both, people got once-weekly semaglutide 1·0mg or once-daily liraglutide 1·2mg, both as a shot under the skin. The second difference is order. When that history was written, liraglutide at 3·0 mg already held a weight approval, an indication then still under investigation with semaglutide. On the heart, the history puts them side by side, noting that both also positively affect cardiovascular outcomes in people with type 2 diabetes. So this is a comparison between two versions of one idea, and the newer one was built to go further on the same target rather than to do something different.

Question 2

What did the one head-to-head trial with semaglutide find?

Accepted Answer

SUSTAIN 10 is the only trial among these sources that put the two in one population. It was a phase 3b, open-label trial in 577 adults with type 2 diabetes who were already taking one to three diabetes tablets. Its main measure was HbA1c, the blood test that reflects average sugar over recent months, and from a starting level of 8·2% the gap at week 30 came to 0·69 percentage points in semaglutide's favour. Weight was the confirmatory secondary measure, and the authors concluded that semaglutide was superior to liraglutide in reducing HbA1c and body weight in those patients. That is a real result, from a real randomised trial, and it is the strongest direct evidence this comparison has. It also describes 30 weeks in people with diabetes at the amounts the investigators chose, which is a narrower thing than the question most readers bring to it.

Question 3

Was SUSTAIN 10 a fair test of liraglutide?

Accepted Answer

Fair to its own question, and that question was practice rather than maximum effect. The investigators compared the anticipated most frequent semaglutide dose (1·0mg) with the liraglutide dose most often prescribed in Europe at the time. That put liraglutide at 1·2 mg, below the 1·8 mg a day used in other trials covered here, such as the 48-week phase 2 liver trial. It was also open-label, meaning participants and staff knew which injection each person was on, which matters most for outcomes people report themselves. None of that overturns the result on blood sugar, which is a lab value. It does mean the trial answers what happens when each is used the way it most commonly was, rather than what each can do at its highest diabetes amount, and those are different questions with possibly different answers. A trial at 1·8 mg against semaglutide's top amount is not among these sources, so that second question stays open rather than answered.

Question 4

Is semaglutide better than liraglutide for weight loss?

Accepted Answer

On the pooled evidence it produces more weight loss, and the size of the gap is easier to state than to trust. A 2025 systematic review of placebo-controlled trials in adults without diabetes puts semaglutide at 2·4 mg weekly at up to 13·9% after 68 weeks, and liraglutide at 3·0 mg daily at up to 5·8% after 26 weeks. Read the weeks before the percentages. One figure was measured at 68 weeks and the other at 26, so part of that gap is time rather than molecule, and the review did not adjust one into the other. The same review reports that no head-to-head RCTs were available, and adds that heterogeneity prevented meta-analysis, meaning the trials were too different to merge into one figure. A 2025 network meta-analysis that did pool them drew on 11 liraglutide trials and found weight loss beyond placebo of more than 10% for semaglutide and tirzepatide. Liraglutide fell below that line. The direction is consistent across these sources, while the size depends on which trials were lined up and for how long.

Question 5

Which causes more side effects, liraglutide or semaglutide?

Accepted Answer

Inside the one direct trial, semaglutide did. The authors found safety profiles generally similar, except for higher rates of gastrointestinal AEs with semaglutide vs liraglutide, meaning more stomach and bowel complaints. Report databases seem to say the opposite. A European analysis counted 16,748 reports for liraglutide against 13,956 for semaglutide over the same period. That is not a contradiction. A report count grows with how many people have used something and for how long, and liraglutide came first, so the count measures exposure as much as harm. The FDA's reports show the two sharing much of their unusual signals. One 2025 analysis found semaglutide flagged for loss of smell, dry mouth, taste change and Bell's palsy, and liraglutide for hoarseness, taste change, tinnitus and Bell's palsy. The trial gives a rate and the databases give a pattern, and only the trial compared like with like.

Question 6

Which keeps more muscle, liraglutide or semaglutide?

Accepted Answer

This is the one comparison where liraglutide comes out ahead, and it rests on a single pooled analysis. A 2025 network meta-analysis of 22 randomised trials in 2,258 participants looked at lean mass, which is everything in the body that is not fat. It found that tirzepatide (15 mg weekly) and semaglutide (2·4 mg weekly) were the most effective for weight and fat mass reduction but were among the least effective in preserving lean mass. Liraglutide sat at the other end of that ranking, as the one molecule in the analysis whose weight reduction came without a significant fall in lean mass. Two cautions belong with that. Less weight lost means less of everything lost, so part of the difference may simply be size of effect. And a ranking from pooled trials is weaker than a trial built to measure muscle on both, which is not among these sources.

Question 7

How does liraglutide compare with tirzepatide?

Accepted Answer

Only indirectly, and the gap is wider than with semaglutide. A 2023 JAMA review of obesity care says that of the six approved long-term medicines, tirzepatide has the greatest effect, with mean weight loss of 21% at 72 weeks. A 2024 review in the same journal shows how differently the two figures are built. Liraglutide's pooled result rests on 18 trials and 6,321 participants, while the tirzepatide 15 mg result rests on 6 trials and 1,972 participants. Those numbers cut both ways. Tirzepatide's effect is far larger, and liraglutide's is measured on three times as many trials, which makes its smaller figure the more settled of the two. Tirzepatide is also a different kind of molecule, described in the same JAMA review as a glucose-dependent insulinotropic polypeptide/GLP-1 agonist, so the pair differ in what they are rather than only in how strong they are. How tirzepatide sits against semaglutide, where a direct trial does exist, is covered on the Semaglutide comparison page.

Question 8

Has liraglutide been tested head to head against exercise?

Accepted Answer

Yes, and it may be the most useful comparison liraglutide has, because it sets the injection against the thing most people try first. A Copenhagen team ran a randomized, head-to-head, placebo-controlled trial in adults with obesity who did not have diabetes, after an 8-week low-calorie diet. At one year, both active arms beat placebo, by 4·1 kg in the exercise group and by 6·8 kg in the liraglutide group. The authors concluded that a strategy combining exercise and liraglutide therapy improved healthy weight loss maintenance more than either treatment alone in those participants. A bone analysis of the same trial added a cost to the injection used alone, reporting that liraglutide treatment alone reduced bone density at key sites in participants more than exercise alone despite similar weight loss. So the comparison does not crown a winner. It shows two tools doing different things, and the pairing doing what neither did alone.

Question 9

How does liraglutide compare with the older weight-loss medicines?

Accepted Answer

It sits in the middle of the older field. The 2024 JAMA review pooled each against placebo and reported orlistat at 3·1% greater weight loss, naltrexone-bupropion at 4·1%, liraglutide at 4·7% and phentermine-topiramate at 8·0%. Each of those works in its own way and has its own side effects, so the order is by weight alone and says nothing about which one suits a given person. The list itself has moved. A 2018 review named 5 drug therapies for long-term weight management, including lorcaserin alongside liraglutide. By 2023, the JAMA list of six medications approved for long-term use named semaglutide, liraglutide and tirzepatide, and lorcaserin was no longer on it. So a list like this is a snapshot of what was on the shelf when it was written. It is worth keeping that in mind before you treat any such table as fixed, since one of the names on the 2018 list had gone five years later.

Question 10

What has liraglutide been combined with?

Accepted Answer

Three pairings carry real data, and each one was tested in a specific group rather than in general. Metformin is the most studied. A 2025 meta-analysis of 19 trials in 1,657 women with polycystic ovary syndrome compared liraglutide plus metformin to metformin monotherapy. A smaller 2024 meta-analysis of the same condition pooled 176 participants from four trials, and liraglutide accounted for 103 of them, against placebo rather than metformin. Exercise is the second pairing, covered above, and insulin is the third, set out on the Liraglutide safety page. One pairing exists only in animals. In mice with a form of heart failure, liraglutide and the diabetes tablet empagliflozin each helped, but no synergism was observed in the combination group of mice. Every other combination is untested among these sources rather than cleared, and a pairing nobody has trialled is not a pairing with a known result.

Question 11

Is Saxenda the same as Wegovy?

Accepted Answer

No, and the mix-up is easy to make, because both are brand names for weight injections built on the same gut hormone. Saxenda is liraglutide, listed on the FDA recall register as Saxenda (liraglutide) Injection, 18 mg/3 mL, given once a day. Wegovy is semaglutide, named that way in the title of a 2025 drug review, Semaglutide (Wegovy) for MASH, and it is given once a week. A third name now sits beside them. A 2026 recall covers a generic liraglutide injection at the same strength, manufactured for Lupin Pharmaceuticals. So two brand names cover two different molecules, and a generic carries the older molecule without the brand. Matching the name on the box to the molecule inside it is the first step in comparing any of them.

Question 12

What else has liraglutide been set against?

Accepted Answer

Liraglutide is old enough to have become a yardstick, so newer molecules are often measured against it. A 2021 dose-finding trial of cagrilintide, an experimental copy of the appetite hormone amylin, assigned 99 participants to liraglutide 3·0 mg as an active comparator. In that trial, weight fell by 6·0% to 10·8% across the cagrilintide arms against 3·0% on placebo, and its abstract does not print the liraglutide figure. In type 1 diabetes, a small completed early-phase trial set liraglutide against golimumab, an immune-system medicine, in people with longstanding disease. Its results do not appear among these sources. Being a comparator is a role in someone else's trial, and the published abstract reports what that trial was built to show rather than what liraglutide did in it.

Question 13

What would settle liraglutide against semaglutide?

Accepted Answer

A trial with four features, and the published record supplies only part of one. The first is one population, randomised between the two. The second is the weight amount of each, 3·0 mg daily against 2·4 mg weekly, rather than the diabetes amounts. The third is one endpoint at one time point, so that a 26-week figure is never set beside a 68-week one. The fourth is enough people and weeks to see side effects as well as weight. The 2025 review of weight trials in adults without diabetes names the gap in its own limitations, where it reports that no head-to-head RCTs were available. SUSTAIN 10 met the first feature and missed the second, since it compared the anticipated most frequent semaglutide dose with liraglutide at 1·2 mg in people with type 2 diabetes. Until a trial with all four reports, the weight comparison is assembled from separate studies rather than measured inside one, and the honest reading is a direction rather than a size.

Liraglutide comparisons and stacks