Is semaglutide more effective than liraglutide for weight loss?

In STEP 8, semaglutide produced the larger average change: 15.8% mean weight reduction at 68 weeks versus 6.4% with liraglutide. That result came from specific weight-management doses in adults without diabetes, alongside diet and activity counseling. It is a group average, not a prediction of one person's response or a substitute for clinical screening.

What is the main difference between liraglutide and semaglutide?

The most practical difference between the injectable products is frequency: liraglutide is generally injected daily, while semaglutide is generally injected weekly. Their approximate half-lives explain the gap—13 hours for liraglutide and one week for semaglutide. Both activate the GLP-1 receptor, but they are distinct molecules with different trial results and dosing schedules.

How do Saxenda and Wegovy compare?

Saxenda contains liraglutide and Wegovy contains semaglutide. STEP 8 directly compared their established injectable weight-management doses: daily liraglutide 3.0 mg and weekly semaglutide 2.4 mg. Mean weight change at 68 weeks was −6.4% and −15.8%, respectively. The prescriber still decides which molecule and schedule fit an individual's history and treatment goal.

How do Victoza and Ozempic compare for type 2 diabetes?

Victoza contains liraglutide and Ozempic contains semaglutide. In SUSTAIN 10, weekly semaglutide 1.0 mg reduced mean HbA1c by 1.7 percentage points and weight by 5.8 kg over 30 weeks; daily liraglutide 1.2 mg reduced them by 1.0 point and 1.9 kg. Those were trial doses and averages, not personal dosing instructions.

Is liraglutide available as a generic?

Yes. An authorized generic of Victoza launched in June 2024, an independent generic followed that December, and the first generic referencing Saxenda was approved and launched in August 2025. These are generics, not compounded preparations. The distinction matters because generic approval and pharmacy compounding follow different regulatory pathways and should not be treated as interchangeable terms.

Can liraglutide and semaglutide be used together?

No. The Saxenda and Wegovy prescribing information advises against combining either product with another GLP-1 receptor agonist. Because liraglutide and semaglutide both act at that receptor, a prescriber treats them as alternatives rather than a routine pair. Any transition between them requires an individualized plan, including timing and dose decisions from the prescriber.

Liraglutide vs Semaglutide: A Clear Comparison

Liraglutide vs semaglutide comes down to a daily versus weekly injection and different results in head-to-head trials. In STEP 8, adults without diabetes assigned to semaglutide 2.4 mg averaged 15.8% weight reduction over 68 weeks, compared with 6.4% on liraglutide 3.0 mg. In SUSTAIN 10, which studied lower diabetes doses, semaglutide also produced larger average reductions in HbA1c and body weight. Those averages do not decide what is appropriate for one person; tolerability, medical history, access and treatment goal still matter.

Liraglutide vs semaglutide at a glance

Both molecules activate the GLP-1 receptor. That signaling affects appetite, gastric emptying, insulin release when glucose is elevated and glucagon release. The difference is not the basic receptor target but how the molecules are engineered and how long they remain in circulation. How semaglutide works explains that pathway in more detail.

Feature	Liraglutide	Injectable semaglutide
Common weight-management brand	Saxenda	Wegovy
Common type 2 diabetes brand	Victoza	Ozempic
Injection rhythm in the head-to-head trials	Once daily	Once weekly
Approximate half-life	13 hours	1 week
Weight-management dose studied in STEP 8	3.0 mg daily	2.4 mg weekly
Diabetes dose studied in SUSTAIN 10	1.2 mg daily	1.0 mg weekly

The daily-versus-weekly split follows the pharmacology. The current Saxenda prescribing information reports a liraglutide half-life of about 13 hours. The Wegovy prescribing information reports about one week for semaglutide. The doses in this table describe published trials, not a self-directed schedule; a prescriber sets the actual dose and escalation pace.

What STEP 8 found for weight management

STEP 8 is the cleanest direct comparison for the weight question. The 2022 JAMA trial randomized 338 adults with overweight or obesity and no diabetes. Both active-treatment groups also received counseling on diet and physical activity. At week 68, estimated mean weight change was −15.8% with weekly semaglutide 2.4 mg and −6.4% with daily liraglutide 3.0 mg, a difference of 9.4 percentage points. At least 15% weight reduction occurred in 55.6% and 12.0% of participants, respectively (Rubino et al., JAMA 2022).

That is a trial average, not a forecast. STEP 8 was open-label for the comparison between active treatments, used specific target doses and enrolled people without diabetes. Its result should not be transplanted into a different dose, population or treatment duration.

What SUSTAIN 10 found for type 2 diabetes

SUSTAIN 10 asked a different question. This 30-week, open-label trial enrolled 577 adults with type 2 diabetes taking one to three oral diabetes medicines. Mean HbA1c fell 1.7 percentage points with weekly semaglutide 1.0 mg and 1.0 point with daily liraglutide 1.2 mg. Mean body weight fell 5.8 kg and 1.9 kg, respectively (Capehorn et al., Diabetes & Metabolism 2020).

The two trials should not be blended into one number. STEP 8 tested weight-management doses in people without diabetes for 68 weeks; SUSTAIN 10 tested diabetes doses in people with type 2 diabetes for 30 weeks. Both reported a larger average change with semaglutide, but against different clinical questions.

What Promise offers

Promise does not offer liraglutide. The GLP-1 options available here are semaglutide and tirzepatide, which is a dual GIP/GLP-1 receptor agonist rather than another version of liraglutide. For readers choosing between the options Promise carries, tirzepatide versus semaglutide is the relevant comparison.

Side effects and discontinuation are trial-specific

Gastrointestinal symptoms were common with both drugs in STEP 8. Gastrointestinal disorders were reported by 84.1% of participants assigned to semaglutide and 82.7% assigned to liraglutide. Most were mild to moderate, transient, and clustered during or shortly after dose escalation. Adverse events led 3.2% of the semaglutide group and 12.6% of the liraglutide group to stop the trial drug. Discontinuation for any reason was 13.5% versus 27.6%.

SUSTAIN 10 did not produce the same pattern at its diabetes doses. Gastrointestinal disorders occurred in 43.9% with semaglutide and 38.3% with liraglutide; adverse events led to premature discontinuation in 11.4% and 6.6%, respectively. That reversal is why neither molecule should be labeled categorically easier to tolerate. Dose, escalation design, population and follow-up all shape the numbers.

Both drug labels also carry important screening questions involving a personal or family history of medullary thyroid carcinoma, MEN 2, pancreatitis, gallbladder disease, severe gastrointestinal disease, pregnancy and glucose-lowering medicines that can raise hypoglycemia risk. A clinician weighs those factors before choosing a molecule.

Brand, generic and compounded are different categories

Not every formulation has the same regulatory status. Saxenda and Victoza are FDA-approved; compounded liraglutide is not. Wegovy and Ozempic are FDA-approved; compounded semaglutide is not. The brand pairs also have different labeled uses: Saxenda and Wegovy are associated with weight management, while Victoza and Ozempic are associated with type 2 diabetes. Semaglutide brand names covers those distinctions without treating the names as interchangeable.

Generic liraglutide changed the access picture. An authorized generic of Victoza launched on June 24, 2024 (Teva, 2024), and the first independent generic referencing Victoza received approval that December (FDA, 2024). The first generic referencing Saxenda was approved and launched in August 2025 (FDA, 2026; Teva, 2025). A generic is not a compounded preparation; it follows a separate drug-approval pathway.

At Promise, semaglutide is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved. A licensed provider may still prescribe a compounded formulation when clinically appropriate; that decision belongs to the patient and prescriber.

How the choice gets made

The practical choice starts with the goal: weight management or type 2 diabetes care. A provider then considers injection frequency, prior response to a GLP-1 medicine, gastrointestinal tolerability, other glucose-lowering drugs, relevant medical history, pregnancy plans and reliable access. Weekly dosing may be simpler to remember; daily dosing also leaves the body more quickly after it is stopped. Neither convenience point overrides clinical fit.

At Promise, a licensed provider reviews every request, and not everyone qualifies. The reviewing provider sets the dose and follow-up plan rather than copying a trial schedule.