Wegovy vs. Saxenda vs. Mounjaro—which is best for weight loss?
In theory, streaming services all deliver the same thing—ad-free escapism from the comfort of your couch. But they vary when it comes to programming, pricing, and other bells and whistles, and those distinctions matter when it comes to choosing between them.
That’s kind of what it’s like when deciding between prescription weight-management medications these days. There are various options and some seem pretty similar on the surface. But dig a little deeper and you’ll spot the subtle-yet-significant nuances that make these medications unique.
Case in point: Saxenda, Wegovy, and the type 2 diabetes drug Mounjaro. They may share the same classification—incretin receptor agonist—but they’re all different drugs that carry different costs, uses, and eligibility. Here’s how to discern between them, so you can figure out with your healthcare provider which may be best for you.
What are Saxenda, Wegovy, and Mounjaro?
These three medications all belong to the same group of drugs called incretin mimetics. Saxenda and Wegovy are glucagon-like peptide 1 receptor agonists, or GLP-1 agonists, and Mounjaro is a dual agonist, impacting GLP-1 and GIP receptors. “The GLP-1 receptor agonist class of medication has been around for many years—since 2005, actually—but has gained a lot more popularity in recent years with changes in their formulation and longer duration of action,” says Dr. Eiriny Eskander, M.D., a board-certified endocrinologist in Encino, California.
Initially, GLP-1 agonists were approved by the FDA only for the treatment of type 2 diabetes. Once evidence pointed to their weight-loss benefits, the agency began to approve some—though not all—of these medications for the treatment of obesity, too.
Saxenda, also known as liraglutide, was the first GLP-1 agonist to be approved by the FDA for the treatment of obesity in 2014. “Saxenda is a daily injection that starts at a low dose and is increased to the maximum dose of 3.0mg daily,” says Eskander. There is another FDA-approved version of liraglutide, Victoza, but that is only approved for the treatment of type 2 diabetes.
Wegovy (Ozempic and Rybelsus)
Wegovy, or semaglutide, is a newer one that was approved by the FDA for the treatment of obesity in 2021. Wegovy “is a weekly injection in which you increase the dose over time to 2.4mg,” says Eskander. Wegovy is the same drug as lower-dose Ozempic and has the same active ingredient as the tablet form branded Rybelsus, but like Victoza, those are only FDA-approved for treating type 2 diabetes.
Mounjaro, a.k.a. tirzepatide, is a medication that activates GLP-1 receptors and paired gastric inhibitory polypeptide receptors. It was approved to treat type 2 diabetes in 2022. This combination can give it certain advantages (more on that below), but it’s only used off-label to treat obesity at the moment. It is expected that the FDA will approve this medication for the treatment of obesity in 2023. Mounjaro is given via a weekly injection, starting at 2.5mg and increasing up to a maximum dose of 15mg.
How do Saxenda, Wegovy, and Mounjaro help you lose weight?
These medications work via several different methods to trigger weight loss. “When you eat, your body makes gastric inhibitory polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1), which are hormones that are released to signal fullness and start to slow down digestion,” says Eskander.
As GLP-1 agonists, Wegovy and Saxenda impact the GLP-1 receptors in your body the same way your natural GLP-1 does, but for longer. “There are GLP-1 receptors in the satiety center of the brain—and the stimulation of these receptors makes you feel less hungry,” says Dr. Sarah Fishman, M.D., a professor of medicine, endocrinology, diabetes, and bone disease at Icahn School of Medicine at Mount Sinai in New York City. Mounjaro, meanwhile, activates the receptors for both GIP and GLP-1. The exact mechanism of how the GIP in Mounjaro works is still fuzzy, according to Fishman, but it appears to enhance the performance of the GLP-1 agonist.
In activating these receptors, not only do GLP-1 agonists make you feel full longer, but they can also help minimize thoughts of food. That can whittle down your cravings and reduce how many calories you eat. On top of that, “they change the way pancreatic and gut hormones are secreted to reduce insulin resistance,” says Fishman. This can ultimately help reduce post-meal spikes in blood sugar—which is one reason why GLP-1 agonists are so beneficial for people living with type 2 diabetes.
Whichever of these medications you and your provider choose, it’s important to remember that these weight-management medications don’t exist in a vacuum. For the best possible results, it’s essential to pair them with healthy lifestyle habits, such as a balanced diet, regular physical activity, quality sleep, and stress reduction—especially to ensure long-term results.
What are the side effects of Saxenda, Wegovy, and Mounjaro?
The safety and side effects of Saxenda, Wegovy, and Mounjaro are largely the same, according to Fishman; they tend to be gastrointestinal, such as nausea, diarrhea, constipation, and abdominal discomfort. This is by no means a complete list of side effects; the full lists can be found on the drug manufacturers’ websites.
Importantly, none of these medications should be taken while pregnant and should be discontinued with your healthcare provider at least two months before trying to become pregnant. No matter which drug you try, some side effects can usually be alleviated by a gradual dosing. Rarely, if they’re intolerable, your provider might consider switching you to a different type of weight-management medication.
Are there any differences in the results of Saxenda, Wegovy, and Mounjaro?
Because they have different active ingredients, there has been at least one study that shows Wegovy may be more effective than Saxenda in terms of weight loss. That study found that people with overweight or obesity who didn’t have diabetes lost more weight—up to 20% more—with Wegovy than similar people did with Saxenda.
Mounjaro “has the additional mechanism of action with GIP—which also has great weight-loss benefits,” says Eskander. In one clinical trial, more than half of participants on 10mg or 15mg doses of Mounjaro lost more than 20% of their body weight over the course of 72 weeks (this compares to another study showing an average 15.8% weight loss with semaglutide and an average 7.4% weight loss with liraglutide over 56 weeks).
While it’s only FDA-approved for type 2 diabetes at this point, it’s been found so effective for weight management that last year the FDA granted its manufacturer, Eli Lilly, a fast-track designation for the investigation of Mounjaro for treating obesity. Reports suggest it could be approved as early as the end of 2023.
Is there any reason for your healthcare provider to choose Saxenda, Wegovy, or Mounjaro over the others for weight loss?
Mounjaro only has FDA approval for type 2 diabetes at the moment, but both Fishman and Eskander anticipate an approval for obesity in 2023 as well. Meanwhile, Wegovy and Saxenda are both approved for obesity—so which one is best? “It has to do with medical history, insurance [coverage], and patient preference,” says Fishman.
Individual insurance plans vary wildly in terms of which prescription weight-management medications they cover (if any). In terms of patient preference, since Wegovy is a weekly injection (as opposed to daily) and provides greater weight loss, Fishman says it’s often a more compelling option compared to Saxenda. Plus, the convenience of a weekly injection makes it more likely that patients will stick with it.
Another concern? Accessibility. “Until early this year, Wegovy was not readily available in pharmacies.” As a result, Fishman found herself writing a lot more Saxenda prescriptions.
The bottom line
The type of weight-loss medication you choose can depend on a variety of factors, like the out-of-pocket cost, availability, and any additional medical conditions you might have. So while it may seem like there are many similar options to choose from, including Wegovy, Saxenda, and Mounjaro, the nuances between them can make it easier for you and your healthcare provider to select the right choice for you.