Ozempic vs. Metformin: Which Is the Weight Loss Winner?
- By Stephanie Anderson Witmer
- Fact-checked by Joy Ferguson
- December 8, 2023
30-Second Takeaway:
- Both Ozempic and metformin are FDA approved to treat type 2 diabetes.
- Both drugs can also help with weight loss and weight management, yet work differently.
- Choosing your best option could come down to your lifestyle and cost.
No doubt you’ve seen Ozempic and metformin in your news feed ad nauseum this year. Both are FDA approved to treat type 2 diabetes, but people are now taking them off-label for a different purpose: to help shed stubborn pounds. So when it comes to Ozempic vs. metformin, which is better for weight control?
The answer is nuanced. “Both medications can facilitate weight loss, but they have distinct mechanisms of action, degrees of effectiveness, risks, and side effects,” says Daniel Maselli, M.D., a board-certified physician in obesity medicine.
Here are the similarities—and differences—you should know about the two treatments if you’re considering talking to your doctor about them for weight loss.
About the Experts
Daniel Maselli, M.D. is a board-certified physician in obesity medicine, internal medicine, and gastroenterology at True You Weight Loss in Atlanta. He trained at Princeton University, UMass Chan Medical School, Duke University Hospital, The Mayo Clinic, and Vanderbilt University Medical Center.
Danielle Kelvas, M.D. is a primary care physician and medical adviser for R’s KOSO. He is a physician advisor for the HCG Institute, a telemedicine company dedicated to assisting patients online with nutrition, weight loss, and sexual health
How Ozempic and Metformin Are Alike
Ozempic and metformin have many similarities, Maselli says. The biggest commonalities:
Both are approved to treat type 2 diabetes
Ozempic and metformin are prescription medications that help treat type 2 diabetes by improving insulin resistance and lowering blood sugar. Metformin scored FDA approval in 1994 (1) to treat type 2 diabetes; Ozempic didn’t get the same greenlight until 2017 (2).
They’re also prescribed for weight loss
Some doctors prescribe Ozempic (and another form of semaglutide, Wegovy) and metformin off-label to people who struggle to lose weight through traditional methods.
But it’s important to remember that neither medication is a magic weight-loss solution, Maselli says. You need to eat well and exercise while taking them to see optimal results.
Both are long-term medications
Masselli notes that both semaglutide (the active ingredient in Ozempic) and metformin are essentially considered to be life-long drugs, and their effects will wear off when you stop. Establishing healthy habits can help you better maintain your body composition if you and your doctor make the decision to stop.
How Ozempic and Metformin Differ
Ozempic is delivered via injection, metformin comes in a pill
Ozempic is delivered by injection, usually once a week. You can give yourself a shot, typically in the thigh, abdomen, or buttocks. In between shots, you have to refrigerate the drug.
Metformin is a pill that you take orally, once or twice a day.
They work in different ways
Semaglutide (the active ingredient in Ozempic) is a GLP-1 receptor agonist, meaning it activates GLP-1 receptors in the pancreas to mimic the production of the hormone GLP-1 (3, 4, 5). This leads to downstream effects “including increased insulin secretion, decreased insulin resistance, and increased energy consumption, all of which lower blood sugar,” Maselli says.
Metformin works by reducing hemoglobin A1C by about 1% to 2%, Maselli adds. A little background is helpful here: When glucose enters the bloodstream, it latches onto hemoglobin. Hemoglobin becomes coated in sugar, like a glazed doughnut—and the more sugar you have hanging onto your hemoglobin, the higher your blood sugar levels will be. The A1c test gives you an average percentage of red blood cells “sugar-coated” over the past three months.
Ozempic vs. Metformin: Which Is Better for Weight Loss?
Both metformin and Ozempic work well in treating type 2 diabetes. But when it comes to weight loss, semaglutide wins the battle.
In addition to lowering blood sugar, semaglutide helps people lose weight by controlling appetite and curbing food cravings. It also improves satiety—meaning it can keep you feeling full for longer, so you don’t feel the urge to reach for those Doritos while watching the game.
“In patients with obesity but without type 2 diabetes, semaglutide facilitates about 15% to 16% loss of body weight in a year,” Maselli says. “In patients with obesity and type 2 diabetes, the average weight loss at a year from the maximum dose of semaglutide is 10%.”
But metformin’s weight loss performance?
“It’s very modest,” Maselli says. “On average, patients will lose between 3% to 6% of their body weight on metformin. To the point where, as an obesity medicine specialist, I rarely prescribe metformin as an anti-obesity medication unless there are compelling reasons against using other anti-obesity medications.”
He does, however, prescribe it to prevent weight gain from certain conditions or medications for which putting on pounds is a common side effect.
TAKING OZEMPIC? CONSIDER THIS
How Do You Choose Between Metformin and Ozempic?
If you’re looking to lose a significant amount of weight, semaglutide or Ozempic is the clear winner.
That said, metformin is typically the first-line therapy in diabetes management, meaning that alongside lifestyle changes, it’s usually the first drug doctors will prescribe if you have type 2 diabetes, to see if it works. That’s because it’s safe and effective, has been widely studied (been around longer), and has relatively few side effects. Metformin might also be your best choice if you only need to lose a little weight.
There are potential side effects for both drugs—and they typically involve gut troubles, as both drugs work in the GI tract, Maselli says. Both can cause nausea, diarrhea, constipation, and vomiting (6).
Your lifestyle may be something to consider, too, when deciding between the two medications. “If you’re a heavy traveler, keeping Ozempic refrigerated can be inconvenient, as is flying with needles,” points out Danielle Kelvas, M.D., a primary care physician and medical adviser for R’s KOSO. Another big plus for metformin? It’s cheap. Like, just a few dollars for a month’s supply cheap.
Ozempic could cost you a lot if you’re in the U.S. List prices hover around $1,000 per prefilled pen that contains four weekly doses if not covered by your insurance plan, for example.
References
1. https://www.ncbi.nlm.nih.gov/books/NBK518983/
2. https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014
3. Collins L, Costello RA. (2023) Glucagon-Like Peptide-1 Receptor Agonists.
4. Shaefer CF Jr, et al. (2015). User’s guide to mechanism of action and clinical use of GLP-1 receptor agonists
5. Shah M, Vella A. (2014). Effects of GLP-1 on appetite and weight.
6. Corcoran C, Jacobs TF. (2023) Metformin.
