Older GLP-1 Agonists: Saxenda, Victoza, and Trulicity in the Modern Era

Written by Dan Cripe, RN, BSN & Marcia Cripe, RN | Last Updated: September 19, 2026

If you've only recently started hearing about GLP-1 medications, it can seem as though the story begins with Ozempic, Wegovy and the newer generation of weight-loss medications. It doesn't. Long before semaglutide and tirzepatide became household names, medications such as Victoza, Saxenda and Trulicity were already using GLP-1 biology to treat metabolic disease.

Those medications are still prescribed today, which can be confusing when newer therapies generally produce greater average weight loss and, in some cases, require fewer injections. Why would someone take Saxenda every day when Wegovy can be taken once a week? Why might a clinician prescribe Trulicity instead of Ozempic? And if you're doing well on an older GLP-1, does the existence of a newer medication mean you should switch?

Not necessarily. These medications belong to the same broad GLP-1 receptor agonist family, but they are not interchangeable versions of the same drug. Their molecules, half-lives, approved uses, dosing schedules and average clinical effects differ, and the medication that looks older on paper may still make sense for the person taking it.

The GLP-1 Family Didn't Start With Semaglutide

Three medications help show how the GLP-1 class evolved:

• Liraglutide is the active medication in Saxenda and Victoza.
• Dulaglutide is the active medication in Trulicity.
• Semaglutide is the active medication in products including Ozempic and Wegovy.

All three activate the GLP-1 receptor, but their pharmacokinetic properties are different. That difference helps explain one of the first things you notice when comparing them: Saxenda and Victoza are injected daily, while Trulicity, Ozempic and injectable Wegovy are generally injected weekly.

The transition from daily to weekly treatment did not happen because scientists discovered an entirely new GLP-1 receptor. Drug developers created molecules that could remain active much longer, extending the duration of treatment from one injection to the next.

That matters because dosing frequency is not simply a convenience feature added to a newer medication. It reflects how the drug was engineered to behave in your body.

Liraglutide Pharmacokinetics and Daily Dosing Limits: Why Is Saxenda Injected Every Day?

If Saxenda and Wegovy both activate GLP-1 receptors, you might reasonably wonder why one requires a daily injection while the other is given only once a week. The answer is largely pharmacokinetics: how long the medication remains active after you take it.

Liraglutide has a half-life of approximately 13 hours. That is long enough to support once-daily dosing, but not long enough to maintain the exposure required for once-weekly treatment.

Semaglutide was engineered to remain active dramatically longer, with a half-life of approximately one week. That prolonged activity allows semaglutide to be administered once weekly while continuing to exert its pharmacologic effects between injections.

Saxenda therefore is not injected every day because daily administration somehow produces better weight loss. It is injected daily because liraglutide does not remain active long enough to support a weekly dosing schedule.

The practical difference is substantial. Daily liraglutide can mean roughly 365 injections per year, while a weekly injectable GLP-1 generally means about 52. But the reason behind that difference is molecular design, not simply that one medication is “stronger” than the other.

Saxenda and Victoza contain the same molecule too

Saxenda and Victoza both contain liraglutide, but they are different FDA-approved products with different treatment programs. This is similar to the distinction between Ozempic and Wegovy: the active ingredient can be the same while the approved indication, dosing and clinical goal are different.

Victoza is used in type 2 diabetes and has cardiovascular-risk-reduction indications in appropriate patients. Saxenda was developed for chronic weight management.

The dosing reflects those different treatment programs. For adults using Saxenda, liraglutide is gradually escalated to 3 mg once daily, while Victoza uses lower liraglutide doses for diabetes treatment.

This distinction is useful well beyond liraglutide. When you compare GLP-1 medications, knowing the active ingredient is only the beginning. You also need to know which branded product, dose and indication are actually being discussed.

Same molecule does not automatically mean same product or same treatment plan.

Saxenda vs. Ozempic: What Changed With Semaglutide?

If your primary treatment goal is weight loss, semaglutide generally produces greater average weight reduction than liraglutide. In this case, researchers have direct comparison data rather than having to compare results from completely separate trials.

The STEP 8 randomized clinical trial compared once-weekly semaglutide 2.4 mg with once-daily liraglutide 3 mg in 338 adults with overweight or obesity who did not have diabetes. At 68 weeks, average body-weight change was −15.8% with semaglutide compared with −6.4% with liraglutide.

Participants receiving semaglutide were also more likely to reach weight-loss thresholds of at least 10%, 15% and 20%. That provides strong evidence that obesity-dose semaglutide can produce substantially greater average weight loss than obesity-dose liraglutide.

Those percentages are group averages, not promises about what will happen to you individually. Some people lose more than the trial average, some lose less, and treatment response varies considerably from person to person.

There is also an important terminology problem with the common search question “Saxenda vs. Ozempic.” STEP 8 did not compare Saxenda with Ozempic as branded treatment programs.

Researchers compared liraglutide 3 mg with semaglutide 2.4 mg. Semaglutide 2.4 mg is the obesity-treatment dose historically associated with injectable Wegovy, not the standard dosing program used for Ozempic.

So if you are specifically comparing the two medications for chronic weight management, the more scientifically accurate comparison is generally Saxenda vs. Wegovy, even though people frequently search for Saxenda vs. Ozempic.

The search term may use the brand name people recognize. The science still has to compare the correct molecule, dose and treatment indication.

Why Didn't Liraglutide Produce as Much Weight Loss?

It would be easy to look at the STEP 8 results and conclude simply that semaglutide is “stronger.” That shorthand may describe the direction of the outcome, but it does not explain why the drugs behave differently.

Semaglutide and liraglutide differ structurally and pharmacokinetically, and semaglutide provides much more prolonged receptor exposure after each dose. The medications were also developed and studied with different dosing and escalation strategies.

Those differences translate into different clinical effects even though both drugs act on the GLP-1 receptor. In STEP 8, gastrointestinal adverse events were common with both medications, occurring in about 84% of participants receiving semaglutide and 83% receiving liraglutide.

That means the larger average weight loss with semaglutide cannot be explained by liraglutide somehow avoiding the gastrointestinal effects associated with GLP-1 therapy. Both groups experienced a high rate of gastrointestinal adverse events, but semaglutide still produced substantially greater average weight reduction.

This is part of what made semaglutide such an important development in obesity pharmacotherapy. It was not the first GLP-1 receptor agonist, but it represented a major step forward in the amount of average weight loss that GLP-1 receptor agonism could produce.

Dulaglutide: Cardiovascular and Glycemic Efficacy vs. Weight Reduction

Trulicity deserves a somewhat different conversation because dulaglutide's primary clinical role is type 2 diabetes treatment rather than chronic weight management. It is a once-weekly GLP-1 receptor agonist that lowers A1C, and its labeling includes cardiovascular-risk reduction for appropriate adults with type 2 diabetes.

Dulaglutide can also produce weight loss. However, Trulicity is not FDA approved as a chronic weight-management medication, which changes how you should interpret comparisons between Trulicity and medications used specifically for obesity.

If someone asks whether Ozempic or Trulicity causes more weight loss, there is evidence that can help answer that question. But weight change may not be the primary reason a person was prescribed Trulicity in the first place.

For someone using dulaglutide primarily for type 2 diabetes, glycemic control and cardiovascular-risk reduction may be central treatment goals. Weight loss can be an additional benefit without being the sole measure of whether the treatment is working.

We have direct comparison data here too

SUSTAIN 7 directly compared once-weekly semaglutide with once-weekly dulaglutide in people with type 2 diabetes who were taking metformin. The trial gives us a useful head-to-head comparison rather than requiring us to line up unrelated studies.

At 40 weeks:

• Semaglutide 0.5 mg produced an average 4.6-kg weight reduction, compared with 2.3 kg with dulaglutide 0.75 mg.
• Semaglutide 1 mg produced an average 6.5-kg weight reduction, compared with 3.0 kg with dulaglutide 1.5 mg.

Semaglutide also produced greater A1C reductions at those compared doses. Taken together, the results show that semaglutide produced greater average weight loss and greater glycemic improvement than the dulaglutide doses studied in that trial.

There is an important limitation, however. Trulicity now has higher approved doses than the 1.5-mg dose used as the higher dulaglutide comparator in SUSTAIN 7.

You should therefore not take the SUSTAIN 7 numbers and assume they precisely quantify every current-dose comparison between Ozempic and Trulicity. They tell us what happened with the specific doses that were tested.

The broader evidence still supports semaglutide as generally producing greater weight reduction. But Trulicity's clinical role was never simply to compete for the largest possible number on the scale.

For many people taking dulaglutide, weight loss is one treatment outcome among several rather than the entire purpose of the medication.

Escalation Strategies When Moving From Daily to Weekly Dosing

If you are taking Saxenda and your clinician recommends switching to Wegovy, it can be tempting to imagine a straightforward conversion between the doses. You might think that if you are taking a certain number of milligrams of liraglutide, there must be an equivalent number of milligrams of semaglutide.

There is not a validated conversion formula like that.

Saxenda and Wegovy contain different molecules. Their milligram measurements are not equivalent measures of GLP-1 potency, and previous tolerance to one GLP-1 receptor agonist does not automatically establish tolerance to a specific dose of another.

When planning a transition, your prescriber may consider several genuinely separate factors:

• your current Saxenda dose and how long you have been taking it
• how well you have tolerated liraglutide
• why you are switching medications
• how much time has passed since your last dose
• your current treatment goals

Those factors make the transition an individualized prescribing decision rather than a mathematical conversion. Choosing your own Wegovy dose because the milligram number appears similar to your Saxenda dose would not reflect how these medications work.

Wegovy has its own escalation schedule

Injectable Wegovy is ordinarily introduced through its own labeled dose-escalation schedule rather than by immediately starting at the maintenance dose. Gradual escalation is used largely to improve tolerability as exposure increases.

Gastrointestinal effects such as nausea, vomiting, diarrhea and constipation can become more noticeable during dose increases. That is one reason dose escalation is built into GLP-1 treatment programs rather than treating the starting and maintenance doses as interchangeable.

If you have tolerated Saxenda, you already have experience with GLP-1 receptor activation. That history may be relevant to your prescriber, but it does not create a validated liraglutide-to-semaglutide conversion formula.

Switching medications should therefore be thought of as starting a different drug with its own pharmacology and dosing plan, not simply exchanging one milligram number for another.

Daily vs. Weekly Can Feel More Different Than It Sounds

Dosing frequency is not merely a statistic on a prescribing-information sheet. It changes how treatment fits into your daily life.

With Saxenda, medication administration becomes part of your everyday routine because you inject once each day. With Wegovy, Ozempic or Trulicity, injection day generally comes once a week.

For some people, weekly dosing is obviously easier. Fewer injections can mean less planning, less injection fatigue and less day-to-day attention to the medication.

For others, a treatment attached to a familiar daily routine can actually be easier to remember than something that happens only once every seven days. Convenience is therefore partly pharmacologic and partly personal.

There is another practical difference as well. When a medication has a shorter half-life, its concentration falls more quickly after the final dose than it does with a long-acting weekly drug.

Semaglutide's approximately one-week half-life means it remains in the body for weeks after the final injection as levels gradually decline. That is not inherently good or bad, but it is part of the pharmacology you are choosing when you compare daily and weekly medications.

When Do Doctors Still Prescribe Older GLP-1s?

If newer GLP-1 medications can produce substantially greater average weight loss, you may wonder why older medications have not simply disappeared. The reason is that medication selection is not a leaderboard.

The drug with the largest average weight-loss percentage is not automatically the best choice for every treatment goal or every patient. Access, tolerability, treatment history and what you are actually trying to treat can all change the decision.

Insurance and formulary coverage

Your insurance plan may cover Trulicity while restricting Ozempic, or it may prefer another medication in the GLP-1 class. An employer-sponsored plan might cover medications prescribed for type 2 diabetes while excluding obesity medications entirely.

Those coverage rules can matter as much as differences in clinical-trial averages. A medication that produces somewhat less average weight loss can still be far more useful than a medication you cannot obtain consistently.

Access is part of treatment effectiveness in the real world. A highly effective medication cannot help you very much if coverage gaps make continued treatment impossible.

Individual tolerance

People do not all tolerate GLP-1 receptor agonists in exactly the same way. The class shares common adverse effects, particularly gastrointestinal symptoms, but individual response still matters.

Someone who struggles with one GLP-1 medication may tolerate another better. Differences in molecule, dose and exposure can matter even when the drugs belong to the same class.

If you are meeting your treatment goals on an older medication and tolerating it well, the existence of a newer drug does not automatically create a medical need to switch. There should be a reason for changing something that is already working.

Familiarity and treatment history

Some people have used liraglutide or dulaglutide successfully for years. In diabetes treatment especially, a GLP-1 receptor agonist may be one part of a broader regimen that has already produced stable glucose control.

Changing a stable treatment solely because another drug is newer may not provide enough additional benefit to justify disrupting a regimen that is working. Treatment history therefore belongs in the decision alongside the newest clinical-trial results.

Newer evidence can create additional options without automatically making an established treatment obsolete.

The clinical goal may not be maximum weight loss

This is particularly important when discussing Trulicity. If your primary objective is managing type 2 diabetes and reducing cardiovascular risk in an appropriate clinical setting, weight loss may not be the only—or even the main—measure of treatment success.

That makes a simple “which medication causes more weight loss?” comparison incomplete. The answer is still useful, but it needs to be interpreted inside the larger clinical goal.

A medication can produce less average weight loss than another option and still be accomplishing exactly what it was prescribed to do.

What About Kidney Disease?

Kidney disease deserves more nuance than the claim that older GLP-1 medications are simply “better for the kidneys.” Liraglutide, dulaglutide and semaglutide do not generally require the type of renal dose adjustment associated with some medications that depend substantially on kidney clearance.

That can make GLP-1 receptor agonists useful in people with impaired kidney function. But kidney disease also changes the safety conversation because treatment-related gastrointestinal symptoms can have greater consequences.

Nausea, vomiting and diarrhea can lead to dehydration. Significant volume depletion can contribute to acute kidney injury, particularly in someone whose kidney function is already impaired or whose renal reserve is limited.

Newer GLP-1 medications also now have substantial kidney-outcome evidence. Ozempic has an FDA-approved indication involving reduction of certain kidney and cardiovascular risks in adults with type 2 diabetes and chronic kidney disease.

Kidney disease therefore is not a simple reason to choose an older GLP-1 over a newer one. It is a reason for individualized medication selection, attention to hydration and appropriate clinical monitoring.

Are Older GLP-1s Less Effective or Just Different?

Both can be true, depending on what outcome you are measuring.

For weight loss, newer therapies have moved the field substantially forward. STEP 8 showed much greater average weight reduction with semaglutide 2.4 mg than with liraglutide 3 mg in adults with overweight or obesity who did not have diabetes.

SUSTAIN 7 likewise showed greater average weight and A1C reductions with the semaglutide doses studied compared with the dulaglutide doses studied in people with type 2 diabetes. Those are meaningful differences, and there is no reason to minimize them.

But “less weight loss” does not mean “useless medication.” Liraglutide and dulaglutide helped establish that GLP-1 receptor agonism could improve metabolic disease and cardiovascular outcomes long before most people outside diabetes care had heard the term GLP-1.

They can still be clinically appropriate treatments today. What has changed is that you now have more options, including medications capable of producing levels of average weight reduction that earlier GLP-1 therapies generally did not achieve.

The important question is therefore not whether an older medication can beat a newer one on every outcome. It is whether the medication you are taking is appropriate for the outcome you actually need.

So Should You Switch to a Newer GLP-1?

If you are taking Saxenda, Victoza or Trulicity and doing well, the existence of Ozempic, Wegovy, Zepbound or newer therapies does not automatically mean you are taking the wrong medication. Start with the problem your current treatment is supposed to solve.

If you are using Saxenda specifically for obesity treatment and are not getting the response you and your clinician are aiming for, discussing a newer obesity medication may make sense. The availability of therapies associated with greater average weight loss gives you additional options that did not previously exist.

If you are taking Trulicity for type 2 diabetes, your glucose is well controlled, you tolerate the medication and your clinician is satisfied with the overall treatment strategy, the calculation may be different. Switching simply because another medication produces more average weight loss may not address the reason you are taking the medication in the first place.

Insurance can change the decision as well. A formulary change may determine which medication you can realistically access, regardless of which option looks most attractive on paper.

Side effects are another legitimate reason to revisit treatment. A medication can technically be effective and still be a poor fit if the adverse effects are difficult to manage.

The more useful question is not simply, “Which GLP-1 is newest?” Ask instead what you are treating, how well your current medication is treating it, and what would actually improve if you changed therapy.

That framing keeps the decision centered on your health rather than on which drug currently receives the most attention.

What to Do With This Information

If you are taking an older GLP-1, you do not need to view your medication as the outdated version of something better. You should understand what it is designed to accomplish and whether it is still accomplishing that goal.

Saxenda and Victoza contain liraglutide. Trulicity contains dulaglutide. Ozempic and Wegovy contain semaglutide.

They share GLP-1 receptor biology, but their pharmacokinetics, dosing schedules, approved uses and average clinical effects differ. Those differences explain why medications within the same broad class can occupy very different roles in treatment.

If weight loss is your primary goal and you are not getting the response you need, newer medications give you reasonable options to discuss with your prescriber. If your current medication is accomplishing the goal that actually matters to you, newer does not automatically mean necessary.

That is the part that gets lost when GLP-1 medications are discussed as though they are competing on a single weight-loss scoreboard. The medication does not need to win the class; it needs to do the job it was chosen to do for you.

Sources

1. Rubino DM, et al. 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.
   https://pubmed.ncbi.nlm.nih.gov/35015037/
2. Pratley RE, et al. Semaglutide versus dulaglutide once weekly in patients with type 2 diabetes (SUSTAIN 7): a randomised, open-label, phase 3b trial. Lancet Diabetes & Endocrinology. 2018;6(4):275–286.
   https://pubmed.ncbi.nlm.nih.gov/29397376/
3. Novo Nordisk. Saxenda (liraglutide) U.S. Prescribing Information.
   https://www.novo-pi.com/saxenda.pdf
4. Novo Nordisk. Victoza (liraglutide) U.S. Prescribing Information.
   https://www.novo-pi.com/victoza.pdf
5. Eli Lilly and Company. Trulicity (dulaglutide) U.S. Prescribing Information.
   https://pi.lilly.com/us/trulicity-uspi.pdf
6. Novo Nordisk. Wegovy (semaglutide) U.S. Prescribing Information.
   https://www.novo-pi.com/wegovy.pdf
7. Novo Nordisk. Ozempic (semaglutide) U.S. Prescribing Information.
   https://www.novo-pi.com/ozempic.pdf