The landscape of pharmacological obesity treatment is rapidly evolving, requiring healthcare providers to stay informed. With a growing number of weight loss medications available, patients often inquire about the most effective options and which one suits them best. The answer is multifaceted, and newer medications aren't always superior. This article provides a detailed comparison of Wegovy and Victoza, two medications in the glucagon-like peptide-1 receptor agonist (GLP-1 receptor agonist) class, to aid in understanding their differences and potential benefits.
Understanding Weight Loss Medications
Before delving into the specifics of Wegovy and Victoza, it's crucial to understand the broader context of weight loss medications. Determining candidacy for these medications starts with assessing Body Mass Index (BMI). A comprehensive treatment plan for obesity can comprise multiple forms of treatment, including medications, diet, exercise, and/or surgery. For each individual case, the doctor and patient should discuss the patient’s current health issues, other medications, and family medical history. The average weight loss varies, and most people regain weight if Anti-Obesity Medications (AOMs) are discontinued. While some weight loss medications are FDA-approved only for adults, some-including semaglutide and liraglutide-are approved for children 12 and older with a BMI >/= 95th percentile.
The Rise of GLP-1 Receptor Agonists
In the 2020s, glucagon-like peptide-1 receptor agonists (GLP-1 receptor agonists) have surged in popularity and media attention. These medications, including semaglutide (Wegovy, Ozempic) and liraglutide (Victoza, Saxenda), mimic the natural hormone GLP-1, which is released from the small intestines in response to food. GLP-1 mimetics improve how the body handles glucose (sugar). Next came a dual receptor agonist, Mounjaro, which is indicated for type 2 diabetes, and Zepbound, which is indicated for obesity.
Wegovy: A Detailed Overview
Wegovy is a brand name for semaglutide, a GLP-1 receptor agonist. It received FDA approval in 2021. Wegovy may also be used for purposes not listed in this medication guide.
Indications and Usage
Wegovy is administered as an injection and approved for use in adults and children aged 12 years or more with obesity (BMI ≥30 for adults, BMI ≥ 95th percentile for age and sex for children) or some adults with excess weight (BMI ≥27) who also have weight-related medical problems. Prescribed for Weight Loss (Obesity/Overweight), Cardiovascular Risk Reduction, Nonalcoholic Steatohepatitis.
Read also: Sustainable weight loss using Wegovy
Dosage and Administration
The dose must be increased gradually over 16 to 20 weeks to arrive at the 2.4 mg dosage. This progression can help to alleviate side effects, which include gastrointestinal symptoms, headache, dizziness, and fatigue. It is intended to be used indefinitely, in combination with a healthy diet and exercise. Food may affect the absorption of semaglutide when taken orally. Talk to your doctor before using alcohol together with semaglutide.
Victoza: A Detailed Overview
Liraglutide is a daily injectable medication that acts on hormones that send signals from the gut to the brain to make the patient feel full quicker and decrease hunger signals. Liraglutide may affect the absorption of other medications that you take by mouth. Talk to your doctor before using alcohol together with liraglutide.
Indications and Usage
Liraglutide is also approved for Type 2 Diabetes, under the brand name Victoza.
Dosage and Administration
Doses start at 0.6 mg to 3 mg a day. Some patients may lose 5-10% of body weight, especially with the higher dose of liraglutide.
Wegovy vs. Victoza: Key Differences and Similarities
Both Victoza and Ozempic belong to the same drug class called GLP-1 receptor agonists. They share some similarities but also have key differences.
Read also: Weekly Wegovy Progress
Dosage and Administration
Victoza is injected once per day, while Ozempic is injected once per week. The dosing for some of these includes a long ramp-up period-up to five months-to reach full dosage.
Target and Mechanism
Liraglutide acts in several regions of the unconscious part of your brain, specifically the hypothalamus, which controls metabolism, and parts of the brain stem responsible for communicating your body’s nutrient status to the hypothalamus. Its actions here appear to reduce hunger in two different ways. First, it helps you to feel full earlier, making smaller meals more satisfying. Although the target for each formulation is the same (the GLP-1 receptor), for glucose control in type 2 diabetes, liraglutide has to (mainly) reach the pancreas. But to achieve weight loss, it has to reach parts of the brain.
Formulations and Approvals
Liraglutide’s original formulation, designed to treat type 2 diabetes, was marketed as Victoza. Its ability to cause weight loss was evident soon after it entered the market. Shortly after, a stronger formulation, called Saxenda, was released, which was intended for weight loss in people with obesity. Victoza is also FDA approved to help regulate blood sugar levels in children ages 10 years and older with type 2 diabetes. Ozempic, on the other hand, is not approved for use in children.
Additional Uses
Ozempic is approved for a use that Victoza isn’t, which is to reduce the risk of worsening kidney disease, kidney failure, and death from cardiovascular disease in adults with type 2 diabetes and chronic (long-term) kidney disease.
Efficacy for Weight Loss
People respond differently and will lose different amounts of weight. But here, we’ll note the average weight loss users can expect. Some will lose more (sometimes much more), others will lose less, and a small proportion won’t respond. For liraglutide, those using the drug to treat obesity will use the stronger one (Saxenda), which typically gives about 10% weight loss.
Read also: Duration of Wegovy Treatment
Comparison in Studies
Researchers looked at semaglutide (the active ingredient in Ozempic) and liraglutide (the active ingredient in Victoza). The findings suggest that semaglutide may be more effective than liraglutide for regulating blood sugar levels long term. More comparison trials are needed to verify these findings.
Side Effects and Precautions
Because all these medicines have the same target in the body, they mostly have the same side effects. The most common are a range of gastrointestinal upsets including nausea, vomiting, bloating, constipation and diarrhoea. These occur, in part, because these medications slow the movement of food out of the stomach, but are generally managed by increasing the dose slowly. Because these are injectables, they can also lead to injection-site reactions.
Common Side Effects
Side effects include nausea, diarrhea, constipation, vomiting, headache, decreased appetite, dyspepsia, fatigue, dizziness, abdominal pain, increased lipase, and renal insufficiency.
Serious Side Effects and Warnings
Victoza and Ozempic have a boxed warning for the risk of thyroid cancer. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about drug effects that may be dangerous. GLP-1 receptor agonists have been found to increase the risk of thyroid tumors in animal studies. However, it’s not known whether these drugs might cause thyroid tumors in humans. Cases of thyroid cancer have been reported in people using Victoza. But it’s unclear whether the drug was the cause.
Cost and Availability
GLP-1s are notoriously costly. The Kaiser Family Foundation estimates the annual net price of Wegovy at $13,600. Insurance coverage varies and will affect many patients’ choices about going on weight loss medications. Fourteen years ago, the older drug cousin of semaglutide (Ozempic and Wegovy) came onto the market. Patents for Victoza and Saxenda have now expried. So other drug companies are working to develop “generic” versions. These are likely be a fraction of current cost, which is around A$400 a month.
The Future of Weight Loss Medications
With fervent consumer demand for weight loss medications, combined with rising obesity rates, more medications are bound for the market in the coming years. Pharmaceutical platform Ozmosi predicts one to two GLP-1 launches annually starting in 2026. specifically for obesity. Lilly is developing at least two new options. The first, orforglipron, is an oral GLP-1 inhibitor that completed a Phase 3 clinical trial in early 2025. It could provide a welcome alternative for people who do not want injections. Phase 3 results expected soon. at 36 weeks. The other, retatrutide, targets GLP-1, GIP, and glucagon. At this writing, it is in Phase 3 clinical trials. In Phase 2, participants lost up to 24.2% of body weight at 48 weeks. Amgen is developing MariTide, a monoclonal antibody designed to increase GLP-1 receptor activity while reducing GIP receptor activity. The once-monthly injection entered Phase 3 clinical trials in March 2025. Researchers continue to study hormones that play a role in appetite for other ways to target obesity with medication. Those of interest include not only GLP-1, but also peptide tyrosine-tyrosine (PYY) and cholecystokinin (CCK). With more options available, doctors will be increasingly able to personalize treatments.