Pinc PeptideThe girly peptide research blog

Compare · updated 8 October 2026

Semaglutide vs liraglutide

The short answer

In STEP 8, a 68-week head-to-head trial in 338 adults with obesity or overweight but no diabetes, weight fell 15.8% on weekly semaglutide and 6.4% on daily liraglutide4. In type 2 diabetes, semaglutide also lowered blood sugar and weight more than liraglutide in SUSTAIN 10, though that trial used less liraglutide than the US maximum dose15. Novo Nordisk, which makes both drugs, funded STEP 8 and sponsored SUSTAIN 1034. Both are FDA-approved, and liraglutide is also approved as a generic in the US67.

At a glance

ComparedSemaglutideLiraglutide
Evidence tierA Two or more large human trialsA Two or more large human trials
Does it work?For long-term weight management: Benefit shownIn a large trial, people lost 14.9% of their weight on average over 68 weeks, versus 2.4% on placebo8. A higher 7.2 mg weekly dose cut weight by 18.7%, versus 3.9% on placebo9.For long-term weight management: Benefit shownIn a 56-week trial, adults lost 8.4 kg on average, versus 2.8 kg on placebo10. In a head-to-head trial, weight fell 6.4% on daily liraglutide versus 15.8% on weekly semaglutide4.
FDAApproved (Wegovy, Ozempic, Rybelsus)611Approved (Saxenda, Victoza, generics)712
US pharmaciesCopies limited since the shortage ended1314Copies allowed while the shortage lasts1516
SportNot banned, but monitored1718Not named; approved in the US, so likely allowed1819
AustraliaPrescription only20Prescription only20
Half-lifeAbout 1 week21About 13 hours12
Taken asSubcutaneous injection once weekly (approved as Ozempic and Wegovy; human trial data)
Oral tablet once daily (approved as Rybelsus, Ozempic tablets and Wegovy tablets; human trial data)
Unapproved “research” vials sold for injection (no quality control; no trials of these products found)		Subcutaneous injection once daily (approved as Saxenda, Victoza and generic liraglutide; human trial data)
Subcutaneous injection combined with insulin degludec (approved as Xultophy)
Fake or illegal products sold outside the legal supply chain, including counterfeit Saxenda pens (no quality control; no trials of these products found)
What it isA modified version of the human gut hormone GLP-1 (94% the same sequence) that switches on the GLP-1 receptor21.A modified version of the human gut hormone GLP-1 (97% the same sequence) that switches on the GLP-1 receptor12.
Brand names and approved uses in the USWegovy injection: weight reduction in adults and in children 12 and older with obesity, lowering heart risk in adults with heart disease and obesity or overweight, and the liver disease MASH with moderate to advanced scarring21. Wegovy tablets: weight reduction and heart risk in adults21. Ozempic injection: type 2 diabetes, including heart and kidney risk reduction22. Rybelsus and Ozempic tablets: type 2 diabetes, including heart risk reduction in high-risk adults23.Saxenda: weight reduction and long-term maintenance in adults with obesity, or overweight plus a weight-related condition, and in children 12 and older with obesity who weigh more than 60 kg12. Victoza: type 2 diabetes in adults and children 10 and older, and heart risk reduction in adults with type 2 diabetes and heart disease5. Generic versions of both are approved7.
Weight loss head to head (STEP 8, 68 weeks)15.8% of body weight lost on 2.4 mg a week, or 1.7 mg for those who could not tolerate 2.4 mg; 70.9% lost at least 10%4.6.4% of body weight lost on 3.0 mg a day; 25.6% lost at least 10%4.
Blood sugar head to head (SUSTAIN 10, type 2 diabetes, 30 weeks)In 577 adults with type 2 diabetes, HbA1c (a measure of average blood sugar) fell 1.7 percentage points on 1.0 mg a week, and weight fell 5.8 kg1.HbA1c fell 1.0 percentage point on 1.2 mg a day, below the 1.8 mg US maximum, and weight fell 1.9 kg15.
Largest heart outcome trialSELECT, 17,604 adults with heart or blood-vessel disease and overweight, no diabetes: heart attack, stroke or cardiovascular death in 6.5% versus 8.0% on placebo over about 40 months24.LEADER, 9,340 adults with type 2 diabetes and high heart risk: heart attack, stroke or cardiovascular death in 13.0% versus 14.9% on placebo over a median 3.8 years25.
Most common side effects in STEP 8Nausea 61.1%, constipation 38.9%, diarrhea 27.8% and vomiting 25.4%4.Nausea 59.1%, constipation 31.5%, diarrhea 18.1% and vomiting 20.5%4.
Stopped because of side effects in STEP 83.2%, and 13.5% stopped for any reason4.12.6%, half of them because of digestive problems, which tended to come while the dose was being raised; 27.6% stopped for any reason4.
Generic versions in the USNone as of 29 September 2026: FDA had only tentatively approved a generic semaglutide injection, from Apotex, on 7 April 2026, and a tentative approval does not allow a product to be sold626.Approved: as of 6 October 2026, FDA listed 11 approved generic liraglutide applications from 9 companies7.
Gray-market vials74 of Finnrick’s latest 196 completed tests failed (37.8%) as of 30 September 202627. Fake semaglutide containing insulin has caused severe low blood sugar28.We found no lab tests of gray-market liraglutide; Finnrick’s analysis of more than 21,000 test requests does not mention it29. In 2023 the UK regulator reported fake Saxenda pens, and five cases in which fake Saxenda and Ozempic pens contained insulin30.

Why one is weekly and the other daily

Both drugs come from Novo Nordisk and work the same way: each switches on the GLP-1 receptor, which raises insulin and lowers glucagon when blood sugar is high, slows the emptying of the stomach and helps regulate appetite1221. Natural GLP-1 lasts 1.5 to 2 minutes in the blood, because enzymes break it down12. Both drugs carry a fatty acid that binds them to albumin, the main protein in blood, so they last far longer31.

Semaglutide, developed after liraglutide, has a longer fatty acid chain, and in rat studies longer chains made these molecules last longer31. It is also changed at one position to resist DPP-4, one of the enzymes that break down GLP-121. Its half-life is about 1 week, against about 13 hours for liraglutide, which is why it is taken once a week rather than once a day1221.

Which causes more side effects?

The two head-to-head trials point in different directions. In STEP 8, digestive side effects were about equally common, affecting 84.1% on semaglutide and 82.7% on liraglutide, against 55.3% on placebo4. But 12.6% of people on liraglutide stopped treatment because of side effects, against 3.2% on semaglutide, and serious adverse events affected 11.0% on liraglutide and 7.9% on semaglutide4.

In SUSTAIN 10, a diabetes trial that used lower doses of both drugs, digestive side effects (43.9% versus 38.3%) and stopping because of side effects (11.4% versus 6.6%) were more common on semaglutide1. The STEP 8 authors say their design may have led more people to stop liraglutide: as its label directs, people who could not tolerate the full liraglutide dose had to stop it and could restart only from the lowest dose, while semaglutide could be lowered to 1.7 mg4.

How do semaglutide tablets compare?

In PIONEER 4, 711 adults with type 2 diabetes took daily semaglutide tablets (up to 14 mg), daily liraglutide injections (up to 1.8 mg) or a placebo2. After 26 weeks, HbA1c fell 1.2 percentage points on the tablets and 1.1 on liraglutide, so the tablets were judged no worse, and weight fell 4.4 kg versus 3.1 kg2. Novo Nordisk funded the trial2.

What happens when Saxenda is discontinued?

FDA’s drug shortage list says Saxenda will be available until it is discontinued in January 2027, and gives discontinuation of manufacture as the reason15. Generic liraglutide rated as equivalent to Saxenda is approved: as of 6 October 2026, 3 of the 11 approved generic liraglutide applications matched Saxenda7. FDA’s shortage records list Teva’s generic of Saxenda as “To Be Discontinued”32.

Questions people ask

Is semaglutide better than liraglutide?

In head-to-head trials it cut more weight and lowered blood sugar more: in STEP 8, adults without diabetes lost 15.8% of their weight on semaglutide versus 6.4% on liraglutide, and in SUSTAIN 10, HbA1c fell 1.7 versus 1.0 percentage points14. Novo Nordisk, which makes both, funded or sponsored both trials34. More people stopped liraglutide because of side effects in STEP 8, and more stopped semaglutide in SUSTAIN 1014.

Is Saxenda the same as Wegovy?

No. Saxenda is liraglutide, injected once a day, and Wegovy is semaglutide, injected once a week or taken as a daily tablet1221. In STEP 8, semaglutide at Wegovy’s 2.4 mg dose cut more weight than liraglutide at Saxenda’s 3.0 mg dose: 15.8% versus 6.4% over 68 weeks4.

What is the difference between Victoza and Ozempic?

Both are Novo Nordisk injections for type 2 diabetes: Victoza is liraglutide, taken daily up to 1.8 mg, and Ozempic is semaglutide, taken weekly up to 2 mg522. In SUSTAIN 10, which compared 1.2 mg of liraglutide with 1.0 mg of semaglutide, HbA1c fell 1.0 versus 1.7 percentage points and weight 1.9 kg versus 5.8 kg1.

Can you switch from Saxenda to Wegovy?

Neither label gives directions for switching from liraglutide to semaglutide; the Wegovy label covers switching only between its own tablets and injection1221. Any switch is a decision for a prescriber.

Can you take semaglutide and liraglutide together?

Their labels advise against it. The Saxenda label says using it with any other GLP-1 receptor agonist is not recommended, and the Wegovy label says the same of semaglutide; both drugs belong to that group1221.

Why is liraglutide taken every day and semaglutide once a week?

Liraglutide’s half-life is about 13 hours, and semaglutide’s is about 1 week1221. Semaglutide, developed later, has a longer fatty acid chain, which in rat studies made such molecules last longer, and a change that protects it from the enzyme DPP-42131.

Go deeper

Sources

  1. 1Efficacy 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, 2020. pubmed.ncbi.nlm.nih.gov
  2. 2Oral semaglutide versus subcutaneous liraglutide and placebo in type 2 diabetes (PIONEER 4): a randomised, double-blind, phase 3a trial The Lancet, 2019. pubmed.ncbi.nlm.nih.gov
  3. 3Research Study Comparing a New Medicine Semaglutide to Liraglutide in People With Type 2 Diabetes (NCT03191396) ClinicalTrials.gov, 15 Oct 2019. clinicaltrials.gov
  4. 4Effect of Weekly Subcutaneous Semaglutide vs Daily Liraglutide on Body Weight in Adults With Overweight or Obesity Without Diabetes: The STEP 8 Randomized Clinical Trial JAMA, 2022. pubmed.ncbi.nlm.nih.gov
  5. 5VICTOZA (liraglutide) injection: prescribing information (SPL version 31) Novo Nordisk via DailyMed (U.S. National Library of Medicine), 17 Nov 2025. dailymed.nlm.nih.gov
  6. 6Drugs@FDA: applications containing semaglutide (NDA 209637, 213051, 213182, 215256, 218316; ANDA 220314) U.S. Food and Drug Administration (openFDA), 29 Sep 2026. api.fda.gov · data query
  7. 7Drugs@FDA: applications containing liraglutide (NDA 022341, NDA 206321, BLA 208583 and 11 ANDAs) U.S. Food and Drug Administration (openFDA), 6 Oct 2026. api.fda.gov · data query
  8. 8Once-Weekly Semaglutide in Adults with Overweight or Obesity New England Journal of Medicine, 2021. pubmed.ncbi.nlm.nih.gov
  9. 9Once-weekly semaglutide 7.2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial The Lancet Diabetes & Endocrinology, Nov 2025. pubmed.ncbi.nlm.nih.gov
  10. 10A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management New England Journal of Medicine, 2015. pubmed.ncbi.nlm.nih.gov
  11. 11FDA approves Novo Nordisk’s Wegovy pill, the first and only oral GLP-1 for weight loss in adults Novo Nordisk (PR Newswire), 22 Dec 2025. prnewswire.com
  12. 12SAXENDA (liraglutide) injection: prescribing information (SPL version 22) Novo Nordisk via DailyMed (U.S. National Library of Medicine), 15 Jun 2026. dailymed.nlm.nih.gov
  13. 13FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize U.S. Food and Drug Administration, 1 Apr 2026. fda.gov
  14. 14Outsourcing Facilities Ass’n v. FDA, No. 25-10758 (5th Cir.) (unpublished, per curiam; revised) US Court of Appeals for the Fifth Circuit, 1 Sep 2026. ca5.uscourts.gov
  15. 15FDA Drug Shortages: Liraglutide Injection U.S. Food and Drug Administration, accessed 7 Oct 2026. accessdata.fda.gov
  16. 16Compounding when Drugs are on FDA’s Drug Shortages List U.S. Food and Drug Administration, 8 Aug 2025. fda.gov
  17. 17The 2026 Monitoring Program World Anti-Doping Agency, Sep 2025. wada-ama.org
  18. 18World Anti-Doping Code International Standard: Prohibited List 2026 World Anti-Doping Agency, 24 Sep 2025. wada-ama.org
  19. 19World Anti-Doping Code International Standard: Prohibited List 2027 World Anti-Doping Agency, 21 Sep 2026. wada-ama.org
  20. 20Therapeutic Goods (Poisons Standard—October 2026) Instrument 2026 (F2026L01327) Federal Register of Legislation, Australian Government, 28 Sep 2026. legislation.gov.au
  21. 21WEGOVY (semaglutide) injection and tablets: prescribing information (SPL version 19) Novo Nordisk via DailyMed (U.S. National Library of Medicine), 30 Jun 2026. dailymed.nlm.nih.gov
  22. 22OZEMPIC (semaglutide) injection: prescribing information (SPL version 20) Novo Nordisk via DailyMed (U.S. National Library of Medicine), 10 Jun 2026. dailymed.nlm.nih.gov
  23. 23RYBELSUS and OZEMPIC (semaglutide) tablets: prescribing information (SPL version 14) Novo Nordisk via DailyMed (U.S. National Library of Medicine), 19 Aug 2026. dailymed.nlm.nih.gov
  24. 24Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes New England Journal of Medicine, 2023. pubmed.ncbi.nlm.nih.gov
  25. 25Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes New England Journal of Medicine, 2016. pubmed.ncbi.nlm.nih.gov
  26. 26Drugs@FDA Glossary of Terms U.S. Food and Drug Administration, 14 Nov 2017. fda.gov
  27. 27Semaglutide: public lab test results (Finnrick product page) Finnrick, 29 Sep 2026. finnrick.com
  28. 28[Insulin intoxications caused by falsified semaglutide] Nederlands Tijdschrift voor Geneeskunde, 29 Jun 2026. pubmed.ncbi.nlm.nih.gov
  29. 29We’d Rather Buy the Future Than Wait For It Finnrick, 10 Jun 2026. finnrick.com
  30. 30Ozempic (semaglutide) and Saxenda (liraglutide): vigilance required due to potentially harmful falsified products Medicines and Healthcare products Regulatory Agency (GOV.UK), 23 Nov 2023. gov.uk
  31. 31The Discovery and Development of Liraglutide and Semaglutide Frontiers in Endocrinology, 2019. pubmed.ncbi.nlm.nih.gov
  32. 32FDA drug shortage records via openFDA: liraglutide injection (11 presentations) U.S. Food and Drug Administration (openFDA), 7 Oct 2026. api.fda.gov · data query

Not medical advice. Neither compound is recommended here. How we grade evidence · Report an error.