Semaglutide vs Liraglutide: Weekly vs Daily GLP-1s on the Evidence

Semaglutide and liraglutide both mimic the gut hormone GLP-1 and come from the same company, Novo Nordisk. The main difference is how long they last: liraglutide has a half-life of about 13 hours and is injected daily, semaglutide about a week and is taken weekly. In the STEP 8 head-to-head trial, semaglutide produced -15.8% mean weight change versus -6.4% with liraglutide.^1,7,8

Liraglutide is the older drug, sold as Victoza for type 2 diabetes and Saxenda for weight management. Semaglutide is sold as Ozempic and the oral Rybelsus for diabetes, and as Wegovy, in injection and tablet form, for weight management and other uses.^7,8 Both carry the same boxed warning about thyroid C-cell tumours in rodents.

Below we compare how the two are built, what the head-to-head and placebo-controlled trials found, how their heart-outcome data differ, and where generics and compounded copies fit in. Nothing here is advice on choosing, switching or dosing. That is a conversation for a prescriber.

At a glance

Property	Semaglutide	Liraglutide
Receptor activated	GLP-1	GLP-1
Maker of the brands	Novo Nordisk	Novo Nordisk
US brands	Ozempic, Rybelsus, Wegovy	Victoza, Saxenda
How often taken	Weekly injection or daily tablet	Daily injection
Half-life (label)	About 1 week	About 13 hours
STEP 8 weight change, 68 weeks	-15.8%	-6.4%
Cardiovascular outcomes trial	SELECT (obesity): HR 0.80	LEADER (type 2 diabetes): HR 0.87
Generic versions	Canada from 2026; none in US	US generics since 2024 (weight: 2025)
Boxed warning	Thyroid C-cell tumours (rodents)	Thyroid C-cell tumours (rodents)
Legal status	Prescription only	Prescription only

Same hormone, different engineering: how each drug is built

Human GLP-1 lasts only 1.5 to 2 minutes in the blood before enzymes break it down.⁸ Both drugs solve that problem by attaching a fatty acid chain that binds albumin, but they do it differently.

• Liraglutide: 97% sequence homology to human GLP-1, with a C16 fatty acid (palmitic acid) attached. Plasma half-life is about 13 hours, which suits once-daily injection.⁸
• Semaglutide: 94% homology, with a longer C18 fatty diacid and a change at position 8 to resist the DPP-4 enzyme. Elimination half-life is about one week, allowing weekly dosing, and an oral tablet form exists.⁷

The longer half-life also means semaglutide stays in the circulation for about five to seven weeks after the last dose, according to its label.⁷ That matters for anyone planning surgery or pregnancy, and is one reason these decisions need a clinician.

Brands and approved uses in the US

• Victoza (liraglutide): type 2 diabetes.
• Saxenda (liraglutide 3 mg): long-term weight management in adults with obesity or overweight with a weight-related condition, and in young people aged 12 and over who weigh more than 60 kg and have obesity.⁸
• Ozempic and Rybelsus (semaglutide): type 2 diabetes.
• Wegovy (semaglutide): long-term weight management (the injection from age 12), reducing major cardiovascular events in adults with established cardiovascular disease and obesity or overweight, and MASH with moderate to advanced fibrosis under accelerated approval.⁷

Head-to-head results: STEP 8, SUSTAIN 10 and the pivotal trials

STEP 8 is the only phase 3 trial comparing the weight-management doses directly. It randomised 338 adults with overweight or obesity, without diabetes, at 19 US sites to weekly semaglutide 2.4 mg, daily liraglutide 3.0 mg, or matching placebos for 68 weeks, alongside diet and activity counselling.¹

• Mean weight change: -15.8% with semaglutide, -6.4% with liraglutide and -1.9% with pooled placebo.
• At least 10% weight loss: 70.9% versus 25.6%. At least 20%: 38.5% versus 6.0%.
• Stopping treatment for any reason: 13.5% on semaglutide versus 27.6% on liraglutide.¹

The earlier diabetes trial SUSTAIN 10 pointed the same way at diabetes doses. In 577 adults with type 2 diabetes, weekly semaglutide 1.0 mg lowered HbA1c by 1.7 percentage points versus 1.0 with daily liraglutide 1.2 mg over 30 weeks, and body weight by 5.8 kg versus 1.9 kg.⁴

The placebo-controlled trials

SCALE, the pivotal liraglutide 3.0 mg trial, enrolled 3,731 adults without type 2 diabetes for 56 weeks. Participants lost a mean of 8.4 kg on liraglutide versus 2.8 kg on placebo, and 63.2% versus 27.1% lost at least 5% of body weight.² STEP 1, the pivotal semaglutide 2.4 mg trial, enrolled 1,961 adults for 68 weeks and reported -14.9% versus -2.4% on placebo.³ Separate trials are not a fair head-to-head, which is why STEP 8 carries the most weight.

Heart outcomes: what LEADER and SELECT did and did not show

Both drugs have completed large cardiovascular outcomes trials, but in different populations, so they answer different questions.

LEADER (liraglutide) randomised 9,340 people with type 2 diabetes and high cardiovascular risk. Over a median 3.8 years, cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 13.0% on liraglutide versus 14.9% on placebo (hazard ratio 0.87). Cardiovascular death was 4.7% versus 6.0%.⁵ LEADER used diabetes doses, not the 3 mg Saxenda dose.

SELECT (semaglutide) enrolled 17,604 adults aged 45 or over with established cardiovascular disease and overweight or obesity but no diabetes. The same composite outcome occurred in 6.5% on semaglutide 2.4 mg versus 8.0% on placebo (hazard ratio 0.80) over a mean 39.8 months.⁶ That trial supports the cardiovascular indication on the Wegovy label.⁷

The Saxenda label does not carry a cardiovascular risk-reduction indication.⁸ Neither trial compared the two drugs with each other, so claims that one protects the heart “more” than the other go beyond the data.

How strong is the evidence, and what are its limits?

Both evidence bases are strong by pharmaceutical standards, with large randomised trials published in major journals. Liraglutide also has more than a decade of real-world use behind it. The limitations are worth knowing, though.

• One sponsor for everything. Novo Nordisk makes both drugs and funded STEP 1, STEP 8, SCALE, SUSTAIN 10 and SELECT; LEADER was funded by Novo Nordisk and the NIH.^1,2,3,5,6
• Open-label head-to-head. In STEP 8 the semaglutide versus liraglutide comparison was open-label, although each drug was blinded against its own placebo.¹ Knowing which drug you take can shape adherence and side-effect reporting.
• A small comparison. STEP 8 had 338 participants, mostly women (78.4%), all at US sites.¹ Results may not transfer neatly to other groups.
• Adherence as an outcome. Liraglutide’s higher dropout in STEP 8 may partly reflect daily injections, which the trial could not separate from tolerability.

What is not in doubt: at their weight-management doses, semaglutide produced more weight loss in the only direct comparison, with similar rates of gastrointestinal side effects.

Side effects and label warnings compared

As drugs in the same class, their side-effect lists are close. In STEP 8, gastrointestinal adverse events were reported by 84.1% on semaglutide and 82.7% on liraglutide, mostly nausea, diarrhoea, constipation and vomiting.¹ In SUSTAIN 10, at diabetes doses, gastrointestinal disorders were slightly more common with semaglutide (43.9% versus 38.3%), as was stopping because of adverse events (11.4% versus 6.6%).⁴

Label warnings both share

• A boxed warning for thyroid C-cell tumours seen in rodents, with human relevance not determined, and contraindication in people with a personal or family history of medullary thyroid carcinoma or MEN 2.^7,8
• Warnings on acute pancreatitis, gallbladder disease, hypoglycaemia with insulin or sulfonylureas, raised heart rate, acute kidney injury from dehydration, and pulmonary aspiration during anaesthesia or deep sedation.^7,8
• Suicidal behaviour and ideation was removed from the warnings sections of both labels in early 2026, following an FDA class-wide review.^7,8

Where the labels differ

Saxenda’s list of common reactions includes injection site reactions and increased lipase.⁸ Wegovy’s list includes dysaesthesia (altered skin sensation) and hair loss.⁷ Neither drug is a controlled substance, and neither is included in standard workplace drug-screening panels, which look for substances such as opioids and THC.

Generics, compounded copies and “research” semaglutide

Liraglutide is now available as a generic in the US. Teva launched the first generic version for type 2 diabetes in June 2024, Hikma followed in December 2024, and on 29 August 2025 the FDA approved Teva’s generic of Saxenda, the first generic GLP-1 indicated for weight loss.¹¹ Generic approval means the FDA has judged the product equivalent to the brand.

Semaglutide has no US generic. During the 2022 to 2025 shortage, compounding pharmacies made copies, but the FDA declared the semaglutide shortage resolved on 21 February 2025, and the grace periods for compounders ended in April and May 2025.¹⁰ In 2026 the FDA proposed excluding semaglutide, tirzepatide and liraglutide from the list of bulk substances outsourcing facilities can use. Our overview of weight-loss peptides in 2026 covers those developments.

The FDA’s current concerns list, updated in September 2026, reports 990 adverse event reports involving compounded semaglutide as of 31 May 2026, including hospitalisations tied to dosing errors. It also warns that semaglutide sodium and acetate salts are not the approved form, and that some sellers label products “for research purposes” while selling them to consumers.⁹ A “research use only” label says nothing about identity or sterility; see what “research use only” really means. We do not give sourcing or dosing guidance for such products.

Checks on a prescribed product

• The name, strength and manufacturer match an FDA-approved brand or generic.
• A licensed pharmacy dispensed it against a prescription.
• No claim that a compounded product is “generic Wegovy” or “the same as” an approved drug.

Legal status in September 2026: US, UK and Canada

United States: both are FDA-approved, prescription-only and not federally controlled. State pharmacy boards oversee compounding and telehealth prescribing, so the details of who may supply them vary by state.

United Kingdom: Saxenda and Wegovy are licensed prescription-only medicines. NHS access follows NICE guidance, and the MHRA regulates private online supply.

Canada: both are prescription drugs. Canada became the first G7 country to approve generic semaglutide in 2026, and on 29 June 2026 Health Canada approved the first generic semaglutide for chronic weight management, Apotex’s Sevmia.¹²

For the wider picture on peptide drugs and what separates an approved medicine from a “research” product, see our research peptides explainer.

Frequently asked questions

Is semaglutide better than liraglutide for weight loss?

In the only direct phase 3 comparison, STEP 8, weekly semaglutide 2.4 mg produced -15.8% mean weight change over 68 weeks versus -6.4% with daily liraglutide 3.0 mg, and fewer people stopped treatment.¹ The trial was open-label, funded by the maker of both drugs and involved 338 people. Which drug suits a person is a clinical decision.

What is the difference between Saxenda and Wegovy?

Saxenda contains liraglutide and is injected daily. Wegovy contains semaglutide and is taken weekly by injection or daily as a tablet. Both are approved for long-term weight management. Wegovy also holds indications for reducing major cardiovascular events in people with established heart disease and for MASH with liver fibrosis.^7,8

Why is liraglutide taken daily and semaglutide weekly?

It comes down to half-life. Liraglutide’s fatty acid chain gives it a plasma half-life of about 13 hours.⁸ Semaglutide’s longer fatty diacid chain and an enzyme-resistant change give it a half-life of about one week, so it stays in the body for weeks after the last dose.⁷

Is there a generic version of liraglutide or semaglutide?

Yes for liraglutide in the US: generics for diabetes arrived in 2024, and the FDA approved the first generic of Saxenda for weight management in August 2025.¹¹ There is no US generic semaglutide. Canada approved generic semaglutide in 2026, including the first for weight management in June.¹²

Do semaglutide and liraglutide have the same side effects?

Largely, yes. Gastrointestinal effects dominate for both, and in STEP 8 they were reported by 84.1% and 82.7% of participants respectively.¹ Both labels carry the same boxed thyroid warning and similar warnings on pancreatitis, gallbladder disease and aspiration during anaesthesia.^7,8

Sources

1. Rubino DM, Greenway FL, Khalid U, et al; STEP 8 Investigators. Effect 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;327(2):138-150. DOI: 10.1001/jama.2021.23619. PMID: 35015037. pubmed.ncbi.nlm.nih.gov
2. Pi-Sunyer X, Astrup A, Fujioka K, et al; SCALE Obesity and Prediabetes NN8022-1839 Study Group. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management. N Engl J Med. 2015;373(1):11-22. DOI: 10.1056/NEJMoa1411892. PMID: 26132939. pubmed.ncbi.nlm.nih.gov
3. Wilding JPH, Batterham RL, Calanna S, et al; STEP 1 Study Group. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989-1002. DOI: 10.1056/NEJMoa2032183. PMID: 33567185. pubmed.ncbi.nlm.nih.gov
4. Capehorn MS, Catarig AM, Furberg JK, et al. 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 Metab. 2020;46(2):100-109. DOI: 10.1016/j.diabet.2019.101117. PMID: 31539622. pubmed.ncbi.nlm.nih.gov
5. Marso SP, Daniels GH, Brown-Frandsen K, et al; LEADER Steering Committee; LEADER Trial Investigators. Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med. 2016;375(4):311-322. DOI: 10.1056/NEJMoa1603827. PMID: 27295427. pubmed.ncbi.nlm.nih.gov
6. Lincoff AM, Brown-Frandsen K, Colhoun HM, et al; SELECT Trial Investigators. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med. 2023;389(24):2221-2232. DOI: 10.1056/NEJMoa2307563. PMID: 37952131. pubmed.ncbi.nlm.nih.gov
7. Novo Nordisk. WEGOVY (semaglutide) injection and tablets: US prescribing information, including boxed warning. DailyMed, US National Library of Medicine; label version published 30 June 2026. dailymed.nlm.nih.gov
8. Novo Nordisk. SAXENDA (liraglutide) injection: US prescribing information, including boxed warning. DailyMed, US National Library of Medicine; label version published 15 June 2026. dailymed.nlm.nih.gov
9. US Food and Drug Administration. FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. Content current as of 1 September 2026. fda.gov
10. US Food and Drug Administration. FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize. 2025. fda.gov
11. Healio. FDA approves first generic GLP-1 indicated for weight loss [news report on Teva’s generic liraglutide 3 mg approval]. 29 August 2025. healio.com
12. Health Canada. Canada approves first generic semaglutide for weight loss [news release]. 29 June 2026. canada.ca

Editorial note: This article is for general information only and is not medical or legal advice. Semaglutide and liraglutide are prescription medicines; use them only as prescribed and supervised by a licensed clinician. Compounded and “research” versions are not FDA-approved. Laws vary by location and change often, so verify the rules that apply where you are. Always talk to a licensed healthcare provider before use, especially if you are under 21, pregnant or nursing, taking medication, or managing a health condition.