Both Ozempic (semaglutide) and metformin are medications used to treat type 2 diabetes, but they have also gained attention as potential weight loss aids. While neither is specifically FDA-approved for weight loss, both have been associated with modest weight reduction. This article explores the differences and similarities between these two drugs to help you understand which might be a better fit for your individual needs.
What are Metformin and Ozempic?
Metformin
Metformin is a widely available generic medication that belongs to a class of drugs called biguanides. It helps regulate how the body processes and uses glucose. Metformin is commonly recommended as a first-line therapy for most adults newly diagnosed with type 2 diabetes, thanks to its long track record, safety profile, low risk of causing low blood sugar, and affordability. It is FDA-approved to treat type 2 diabetes in people 10 years and older, making it the only oral antihyperglycemic drug with FDA approval for children as young as age 10.
Ozempic
Ozempic is the brand name for an injectable version of semaglutide. Semaglutide is a GLP-1 receptor agonist, meaning it mimics a naturally occurring hormone in your body called glucagon-like peptide-1 (GLP-1). GLP-1 is a hormone naturally released after eating that signals the body to reduce appetite, slow digestion, and stabilize blood sugar until it’s time to eat again.Ozempic is usually added when blood sugar remains high despite metformin, or for people who would benefit from greater weight loss or cardiovascular protection (such as those with existing heart disease) or kidney protection (those with chronic kidney disease).
How They Work
Metformin
Metformin lowers the amount of glucose that your liver makes and boosts insulin sensitivity. It improves how the body processes sugar and reduces insulin resistance. It is available as a generic drug and under brand names like Glucophage®, Glumetza®, and Fortamet®.
Ozempic
Ozempic mimics the effects of a gut hormone called GLP-1. It triggers your pancreas to release more insulin and slows down how quickly food leaves your body. It also sends signals to your brain that you’re full, which can lead to weight loss. Because Ozempic slows down how fast food moves through your digestive tract, it can decrease your appetite and result in lower calorie consumption.
Read also: Berberine and Metformin
Dosage and Administration
Metformin
Metformin is a pill or liquid that’s taken once or twice a day. There's also an extended-release formula that breaks down more slowly and is taken once a day with your evening meal. You usually start with 500 milligrams at breakfast and dinner, or 850 milligrams at breakfast. Your doctor may increase your dose if your blood sugar isn’t controlled. Metformin is a biguanide that is taken by mouth up to a few times daily.
Ozempic
Ozempic is an injection that you give yourself once a week. It comes in a disposable push-button pen that’s easy to use. You will inject yourself with a prefilled pen in your upper arm, thigh, or stomach once a week. Because it takes time to adjust to the medicine, the dosage increases over months. You’ll begin with 0.25 milligrams for four weeks, and then you take 0.5 milligrams a week for at least another four weeks. You can have up to 2 milligrams each week. Ozempic (semaglutide) is an injectable GLP-1 receptor agonist, meaning it mimics a naturally occurring hormone in your body called glucagon-like peptide-1. It is injected under the skin once a week.
Effectiveness for Weight Loss
Metformin
Experts classify metformin as a weight-neutral treatment option for patients with type 2 diabetes. Studies show that taking metformin can lead to a 5 to 7% weight loss over several months to a year. The Diabetes Prevention Program (DPP) found that people who made lifestyle changes lost more weight than those who took metformin alone. Most of the weight loss occurs in the first 3 to 6 months, then often plateaus. Lifestyle factors (like diet and exercise) significantly enhance results.
Ozempic
Weight loss with Ozempic is seen in people with type 2 diabetes, as well as those without diabetes but who are overweight or obese. Studies show that people taking semaglutide, the active ingredient in Ozempic, lost about 15% of their body weight after 16 months. The semaglutide in Ozempic tends to produce faster and more significant weight loss, while metformin leads to more gradual changes.
Cost and Availability
Metformin
For cost-sensitive patients, metformin is often available for as little as $4-$15/month as a generic. Widely available as a generic medication, metformin typically costs under $30 per month, with prices ranging from $4 to $20 for a 30-day supply of 500 mg tablets. Brand-name versions can be much more expensive, with prices starting around $150-$200 for a 30-tablet pack of 500 mg. Prices for Metformin may vary depending on the pharmacy, location, and formulation (immediate vs. extended-release). IR metformin is especially affordable-some pharmacies offer it for as little as $2 a month with a coupon or discount program. ER metformin can cost a bit more due to the way it’s formulated.
Read also: Comprehensive Study: Metformin and Phentermine/Topiramate
Ozempic
Ozempic, being brand-only, usually costs $850-$1,100/month without insurance, though copay assistance programs and insurance coverage can lower out-of-pocket expenses to $25-$45 monthly in some cases. The manufacturer of Ozempic is currently offering Ozempic for $499/month for certain patients without insurance. Ozempic® costs about $998 per month without insurance. If you need to go beyond the 2 mg dose of semaglutide, you will have to move to Wegovy®, which goes as high as 2.4 mg. Wegovy® can cost more than Ozempic®, though there are ways to save.
Side Effects
Metformin
Both medications commonly cause gastrointestinal side effects. Metformin causes diarrhea by changing gut bacteria, affecting bile acid absorption, blocking water absorption in the intestines, and increasing gut-stimulating hormones. The most common side effects of metformin include stomach pain or upset, diarrhea, nausea, bloating and gas, heartburn and indigestion, headache, and a metallic taste. Additionally, metformin can raise the risk for lactic acidosis. If you take metformin without food you may end up with an upset stomach, especially if you are just starting treatment. Long-term metformin use can lower B12 levels, leading to fatigue, numbness, tingling in the hands and feet, weakness, pale/yellowish skin, and memory issues.
Ozempic
Both medications commonly cause gastrointestinal side effects. With Ozempic®, nausea, vomiting, diarrhea, constipation, and stomach discomfort are fairly common at first. Reports of pancreatitis, gallbladder disease, and ileus in some users. The most common side effects of Ozempic include nausea, diarrhea, constipation, throwing up, bloating and gas, and heartburn and indigestion. Ozempic has an FDA-boxed warning about a potential risk of thyroid C-cell tumors, including medullary thyroid carcinoma (MTC).
Drug Interactions
Ozempic and metformin can interact with other medications, leading to potentially serious side effects. Certain medications, such as corticosteroids, oral contraceptives, diuretics, and calcium channel blockers, can affect the body’s ability to manage blood sugar levels. Metformin can interact with carbonic anhydrase inhibitors, leading to an increased risk of lactic acidosis. Ozempic delays gastric emptying, which may affect the absorption of oral medications.
Taking Metformin and Ozempic Together
Yes. Studies show no interaction between the two medications. Since they work differently, they are often prescribed together for better blood sugar control. Healthcare providers typically start with metformin, add Ozempic if needed, and encourage patients to maintain regular communication about side effects or changes in health status. During clinical studies submitted to the FDA for approval, some patients with type 2 diabetes took both Ozempic and metformin.
Read also: Health Benefits of Metformin
Precautions
Ozempic has a boxed warning for the risk of thyroid cancer. Metformin has a boxed warning for the risk of lactic acidosis.
Switching Between Medications
You can switch between Ozempic® and metformin, but it’s not something to do on your own. They’ll look at things like your current dose, how you’ve been responding to treatment, and whether you’ve had any side effects.
Reasons to switch to Ozempic®:
- You need more weight loss support: Since Ozempic® is generally more effective for weight loss than metformin, someone who hasn’t gotten the results they want with metformin might consider switching to Ozempic®.
Reasons to switch to metformin:
- You may be having uncomfortable side effects: Everyone reacts to medications differently.
- Cost or insurance coverage: Though both are rarely covered by insurance for weight loss, if yours covers one and not the other, you may want to switch.
If you switch from Ozempic® to metformin, you’ll likely lose the appetite-suppressing effect of Ozempic®, which may make it harder to manage hunger and weight loss. Metformin can still help control appetite, but it doesn’t slow digestion or directly impact appetite the way Ozempic® does.
Who Should Consider Each Medication?
Metformin
Metformin is generally safe for most people, but there are a few exceptions. It is often prescribed for prediabetes, insulin resistance, and PCOS. It's a good option for people with PCOS who don’t need to lose weight. Doctors prescribe metformin to lower blood sugar levels in people with prediabetes. Metformin is more likely to be covered by health insurance.
Ozempic
While Ozempic® can be effective for weight loss, it’s not safe for everyone. People with a BMI of 27 or higher and at least one weight-related condition. For people without diabetes, both medications may aid in weight loss, but Ozempic® generally leads to stronger appetite control and greater weight reduction. Ozempic may be more appropriate for someone with Type 2 diabetes and heart disease because it can reduce the risk of cardiovascular problems. Ozempic isn't approved to treat prediabetes. As a result, your health insurance probably won't cover it.
Lifestyle Changes
Losing weight with Ozempic® or metformin doesn’t look the same for everyone. Lifestyle factors (like diet and exercise) significantly enhance results.
What Happens When You Stop Taking the Medication?
Metformin and Ozempic® can help you lose weight, but they don’t permanently change the way your body works. If you stop taking them, some or all of the weight you lost may return, especially if lifestyle habits don’t change. It’s possible to gain weight back after stopping Ozempic®, but it’s not a given!
Slow Tapering
Instead of stopping Ozempic® all at once, easing off gradually may make a big difference. These findings are a good reminder that how you stop Ozempic® matters. Talk to your doctor about a personalized plan that includes both a thoughtful taper and a realistic approach to eating and exercise.