What you’ll learn:
- Rybelsus® and metformin are both pills that are approved for managing type 2 diabetes, but they can also be prescribed off-label for weight loss.
- Rybelsus® and metformin work differently in the body to control blood sugar and they have different pathways that lead to weight loss.
- Both medications result in similar amounts of weight loss when taken for a year.
If you’re exploring options for weight management, you’ve probably come across the growing list of medications being used to support weight loss. Injectable GLP-1 receptor agonists containing semaglutide—like Ozempic® (used off-label) and Wegovy®—along with tirzepatide-based options like Mounjaro® (off-label) and Zepbound®, tend to get most of the attention. And for good reason—they’re among the most effective options available.
You might also hear about Rybelsus® and metformin. Like Ozempic®, both were originally developed to treat type 2 diabetes and have shown some potential for weight loss. They’re taken in pill form, which can be appealing to some. While they tend to be less effective for weight management compared to the injectable options, they do have other benefits we’ll discuss.
And if you’re choosing between these two, it’s good to know which one might work better for weight loss—and to understand the differences in pricing, potential side effects, and what to expect with each medication.
Let’s break down what these medications can (and can’t) do—so you can better understand where they fit into the bigger picture.
Rybelsus® vs. metformin: How do they work?
How do these medications designed to treat type 2 diabetes help people lose weight? Let’s break it down.
- Rybelsus® contains the same active ingredient (semaglutide) as Ozempic® and Wegovy® but in tablet form rather than an injection. Like other GLP-1 receptor agonists, Rybelsus® mimics GLP-1, a hormone your body makes in response to food and other activities that helps lower appetite, slow digestion, and promote a feeling of fullness. This helps you make better food choices.
- Metformin works in a completely different way. It reduces glucose production in the liver, improves insulin sensitivity, and helps the body use sugar more efficiently. While not primarily an appetite suppressant, some people experience moderate weight loss due to lower insulin levels and reduced sugar cravings.
Rybelsus® vs. metformin: The differences
Both Rybelsus® and metformin are pills primarily used to manage type 2 diabetes, but they work in completely different ways, have different side effects, and vary a lot in cost. Whether you’re considering them for diabetes or using them off-label for weight loss, understanding the differences can help you choose what’s best for your health and budget. Here’s how Rybelsus® and metformin stack up.
How you take them
Both medications come in pill form, but metformin offers a lot more flexibility in how it’s taken. It’s available as regular tablets, extended-release tablets, and even a liquid version. Depending on the type, metformin is usually taken once or twice a day with meals to help reduce side effects.
Taking Rybelsus® is a bit more specific. It must be taken once a day, first thing in the morning, on an empty stomach. You need to wait at least 30 minutes before eating, drinking, or taking any other medications. That routine can take some getting used to, especially if your mornings are rushed.
What they cost
Metformin is likely to be significantly less expensive than Rybelsus. Here’s an overview:
- Rybelsus®: Rybelsus® costs about as much as Ozempic, $998 per month without insurance. What you’ll actually pay depends on your insurance plan, coverage type, and whether you’re using it for diabetes or weight loss. Learn more about the costs of Rybelsus®.
- Metformin: Metformin costs much less, with prices ranging from $4 to $20 for a 30-day supply. It’s widely available as a generic medication, unlike Rybelsus. If you need to take brand-name versions for any reason, they can be more expensive. Learn more about the costs of metformin.
Insurance coverage
Insurance coverage can be tricky with these two medications. Let’s take a look:
- Rybelsus®: Insurance coverage for Rybelsus® varies, but it is typically not covered when used for off-label purposes, such as weight loss. Even when covered for type 2 diabetes, it sometimes comes with higher copays (around $50–$150 per month) because it is often considered a specialty drug. Check out our 2025 Rybelsus® pricing guide.
- Metformin: Metformin is also typically only covered for type 2 diabetes, prediabetes, and polycystic ovary syndrome (PCOS). But, if you don’t have insurance or your insurance doesn’t cover it, metformin is still affordable for most people. Most insurance options will cover extended-release and brand-name versions for diabetes, but the person may be required to try the immediate-release version first due to the lower cost. Learn more about metformin coverage in our 2025 guide.
Only metformin is available as a generic
Metformin is available in a generic form, making it more affordable and widely accessible. It has been around for decades—approved in the U.S. as early as 1995—and its patent has long since expired. That’s why you’ll find so many low-cost versions at pharmacies, often just a few dollars with insurance or discount programs.
Rybelsus®, on the other hand, doesn’t have a generic version. It’s a relatively new medication, approved by the FDA in 2019, and remains under patent protection. That means only the original manufacturer (Novo Nordisk) can sell it, which keeps the price significantly higher.
As for when a generic might become available, that usually depends on how long the patent lasts, which can be up to 20 years from the original filing date. A generic version of Rybelsus® may not hit the market for several more years. Until then, cost can be a major factor for anyone considering it.
Rybelsus® vs. metformin: The similarities
While Rybelsus® and metformin work differently, they share some important similarities that could influence your decision. Understanding these common traits can help you and your healthcare provider determine which medication best aligns with your health goals and lifestyle.
Both were designed for blood sugar control
Both metformin and Rybelsus® were created to help manage type 2 diabetes by lowering blood sugar levels, but they do it in different ways.
Metformin works by helping your body use insulin more effectively. It also lowers the amount of sugar your liver makes and reduces how much sugar your body absorbs from food. Essentially, it helps your body regulate blood sugar levels to prevent them from becoming too high after meals.
Rybelsus® works a little differently. It mimics a hormone your body naturally makes called GLP-1, which helps your pancreas release the right amount of insulin when your blood sugar rises. It also slows down how fast food leaves your stomach, which helps keep blood sugar levels steady, and often makes you feel full longer.
Even though both medications were designed for diabetes, they’ve also shown some potential to help with weight loss. That’s not their main purpose, so using them for weight loss is considered “off-label,” meaning it’s not officially FDA-approved for that use. But for people who are looking to lose weight or have metabolic health issues, this side effect can be a bonus.
They come as pills you swallow
Unlike injectable GLP-1 medications like Ozempic®, both Rybelsus® and metformin are available in tablet form, making them convenient for people who prefer oral medication.
Can you switch between Rybelsus® and metformin?
You can switch between these two medications, but the process isn’t as simple as swapping one pill for another. Since these medications work differently, the transition can bring noticeable changes, and it’s important to work with your doctor to ensure a smooth adjustment.
Here are a few reasons why someone might want to switch:
- You need more weight loss support: If you find you’re not getting the weight loss results with your current medication, you might want to switch to the other one.
- You may be having uncomfortable side effects: Medications affect everyone differently, and you may have worse side effects with one than the other.
- Your insurance may cover one but not the other: Although both are rarely covered by insurance for weight loss, if yours covers one but not the other, you may want to consider switching.
Here’s what you can expect when switching medications:
If you switch from Rybelsus® to metformin
If you switch from Rybelsus® to metformin, you may notice changes in your appetite and digestion. As a GLP-1 medication, Rybelsus® slows down how quickly food leaves your stomach and helps you feel full longer, so when you stop taking it, hunger might come back more quickly. Metformin doesn’t have the same strong appetite-suppressing effect as Rybelsus®.
If you switch from metformin to Rybelsus®
Switching from metformin to Rybelsus® can feel like a big change. You may feel fuller faster and stay full longer, which can help you eat less and potentially aid in weight loss. But be prepared for some different side effects like nausea or upset stomach, especially at first. The dose is usually started low and gradually increased to help your body adjust.
Switching medications is a personalized process, and how your body reacts will depend on your metabolism, lifestyle, and medical history. Keep in close communication with your doctor and track any changes in appetite, energy levels, weight, and digestion. If the adjustment proves challenging, your healthcare provider may suggest alternative dosing strategies or additional support to help maintain progress.
Rybelsus® vs. metformin: Which is better for weight loss?
When it comes to weight loss, both Rybelsus® and metformin can help, but they work in different ways and offer different levels of effectiveness. Choosing between them isn’t just about which one helps you lose more weight—it’s also about cost, accessibility, and what fits your lifestyle best.
Rybelsus® vs metformin: How much weight can you lose?
While these medications are very different, research shows similar weight loss outcomes, with metformin demonstrating slightly better results than Rybelsus®. Here’s a look:
- Rybelsus® – One trial found that people taking Rybelsus® could lose an average of 4% of their body weight over the course of a year. This is significantly less than the average of 15% of body weight lost with injectable semaglutide medications like Wegovy.
- Metformin – In studies, people taking metformin have lost an average of 5% of their body weight over the course of one year.
How long does it take to see results?
While both medications can aid in weight loss, the rate of weight loss depends on the dose, metabolism, and other lifestyle factors like diet and exercise. Below, we’ll walk you through the typical weight loss timeline for each medication in terms of the average percentage of body weight lost over time.
- At 3 months:
- People taking Rybelsus® or metformin may experience slight weight reduction during this timeframe, but results can vary.
- At 6 months:
- At 1 year:
Who can take Rybelsus® or metformin for weight loss?
While neither Rybelsus® nor metformin is FDA-approved for weight loss, they can help people lose some weight. Here’s a look at who might be a good candidate:
Rybelsus® can be prescribed to people with a:
- BMI of 30 or higher
or
- BMI of 27+ with a weight-related health condition (such as high blood pressure or high cholesterol)
Metformin is often prescribed to those with a:
- BMI of 30 or higher.
or
- BMI of 27 or higher and at least one weight-related condition.
- In some cases, people with a BMI of 25 or higher may qualify, especially if they have insulin resistance, PCOS, or prediabetes.
Who shouldn’t take Rybelsus® or metformin?
Not everyone is a good candidate for these medications. Here are some situations where Rybelsus® or metformin might not be the right fit:
Rybelsus®
You can’t take Rybelsus, or any GLP-1, if you:
- Have a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Are allergic to any of its components
- Are pregnant, planning to become pregnant, or breastfeeding
Ask your doctor if Rybelsus® is right for you if you have:
- A history of severe gastrointestinal disease or pancreatitis
Metformin
You can’t take metformin if you have:
- Severe kidney disease
- History of lactic acidosis or metabolic acidosis
- Known allergy to metformin or any of its components
- Unstable liver disease or severe heart failure
If you take metformin or Rybelsus® to lose weight, will you need to keep taking them forever?
The answer depends on your personal health goals, how well the medication is working for you, and whether you’re managing underlying conditions like type 2 diabetes or insulin resistance. Some people use these medications long-term, while others stop once they’ve reached their target weight. Here’s what happens when you stop taking these medications:
- Weight regain is possible – If lifestyle habits aren’t maintained, stopping the medication could lead to increased appetite and potential weight regain.
- Blood sugar levels may fluctuate – For those with diabetes or prediabetes, stopping metformin or Rybelsus® may lead to higher blood sugar levels over time.
- Your body may take time to adjust – You might notice changes in appetite, digestion, or energy levels as your system adapts to the absence of the medication.
Unlike some medications that need to be tapered off carefully, most people can stop taking metformin or Rybelsus® without a strict tapering schedule. That said, doctors often suggest easing off gradually, especially if you’ve been on them for a while. It gives your body time to adjust and can help prevent things like blood sugar spikes or increased appetite.
No matter what you decide, long-term weight loss really comes down to the habits you build. These medications work best when paired with consistent, healthy routines—like eating nutrient-rich meals, staying active, and being mindful of hunger cues.
Metformin vs. Rybelsus®: Costs and insurance
When choosing between metformin and Rybelsus®, the cost is a major factor to consider. These medications have very different price points, and insurance coverage (or lack of it) can make a significant difference in what you pay out-of-pocket.
Rybelsus®
The list price for Rybelsus is about $998 per month without insurance, regardless of the dose taken (3 mg, 7 mg, or 14 mg). Insurance coverage is unlikely for weight loss.
For more information about costs and coverage, see our guide on Rybelsus® costs in 2025.
Metformin
Metformin prices vary depending on whether you are prescribed the generic medication or a brand-name version, as well as whether you require the immediate-release (IR) or extended-release (ER) form.
- IR vs. ER: If you experience uncomfortable side effects with immediate-release metformin (IR), your doctor might suggest switching to the extended-release (ER) version. Both versions are available as generics, which helps keep costs low.
- Brand-name metformin: Glucophage®, Fortamet®, and Glumetza® and any other extended-release (ER) versions can be more expensive, ranging from $1,000 to $2,000 a month without insurance. Since generic versions are widely available, most people opt for those to keep their costs low, only switching to brand names if they’ve had trouble tolerating the generic version. For more information, refer to our guide on metformin costs for 2025.
Rybelsus® vs. metformin: Side effects and safety issues
While side effects with both of these medications tend to be mild and temporary, they both have serious side effects and warnings associated with them. Understanding what’s normal, what might improve over time, and when to consult your doctor can help you manage these medications effectively.
Common side effects
When starting Rybelsus® or metformin, some digestive changes are common as your body adjusts to the medication. Here’s a look at what you might experience:
Rybelsus®
- Nausea
- Vomiting
- Diarrhea or constipation
- Stomach pain
- Fatigue
Metformin
- Nausea
- Diarrhea
- Stomach pain
- Loss of appetite
- Metallic taste in the mouth
Most of these side effects improve over time as your body adapts. If they persist or worsen, consult your healthcare provider for guidance on managing them.
Serious side effects and warnings
While most people tolerate these medications well, there are a few rare but serious side effects to keep an eye on. If you experience any of these, you should get immediate medical attention.
Rybelsus®
- Medullary thyroid cancer (MTC) risk – Animal studies suggest a potential link, though this hasn’t been confirmed in humans. Watch for swelling in the neck, hoarseness, or difficulty swallowing.
- Pancreatitis: Symptoms include severe abdominal pain that radiates to your back, with or without vomiting.
- Vision changes: If you notice any sudden changes in your vision, get immediate medical attention.
- Low blood sugar (hypoglycemia): Low blood sugar is most likely in people who are also taking medications for diabetes. Symptoms include dizziness, shakiness, blurred vision, and a fast heartbeat.
- Kidney problems: Diarrhea, nausea, and vomiting can cause dehydration and worsen kidney issues. Go to the emergency room if you experience decreased urination, swelling in your ankles or legs, fatigue, or shortness of breath.
- Gallbladder problems: Symptoms include upper abdominal pain, fever, jaundice, or clay-colored stools.
- Allergic reaction: Symptoms include swelling of the face, lips, tongue, or throat, difficulty breathing or swallowing, or a rapid heartbeat. Get immediate medical attention if you’re having an allergic reaction.
Metformin
- Lactic acidosis (rare but serious) – Symptoms include severe fatigue, muscle pain, difficulty breathing, or sudden weakness. Drinking too much alcohol while taking metformin can lead to this serious metabolic condition that requires immediate attention.
- Kidney issues – Watch for changes in urination, swelling in the legs, fatigue, or confusion.
- Vitamin B12 deficiency – Long-term metformin use can lower B12 levels, leading to fatigue, numbness, tingling in the hands and feet, pale/yellowish skin, and memory loss.
Keep in mind that these side effects are rare, and many people use these medications without issues. If you have any worries, chat with your healthcare provider.
For a detailed breakdown of potential risks and safety considerations, visit the Rybelsus® safety page or the metformin safety page.
Rybelsus® vs. metformin: Dosage and administration
Taking Rybelsus® and metformin is a little different from other meds, so it helps to know what to expect. Understanding how to take them—and how your dose might change over time—can make it easier to stay on track and feel more confident about your treatment.
Rybelsus® is a once-daily tablet taken on an empty stomach in the morning. You’ll need to wait at least 30 minutes before eating, drinking, or taking other medications for it to work effectively.
- Starting dose: People begin with 3 mg once daily for the first 30 days to allow their body to adjust.
- Dose increases: After about a month, your doctor will increase your dose to 7 mg and then 14 mg. The timing between dose increases will depend on side effects and how quickly you’re losing weight or how well your blood sugar is controlled.
- Maximum dose: 14 mg daily
Metformin is typically taken twice or three times daily with meals to help reduce stomach discomfort. It also comes in an extended-release (ER) form, which is taken once daily.
- Starting dose: Everyone begins with 500 mg or 850 mg once daily to minimize digestive side effects.
- Dose increases: The dosage is gradually increased by 500 mg every 1 to 2 weeks, depending on how well your body tolerates it.
- Maximum dose: 2,000 to 2,500 mg daily.
Metformin or Rybelsus®: Which is right for me?
Deciding between metformin and Rybelsus® depends on your health goals, budget, and how your body responds to each medication. While both are used for blood sugar management and weight loss, they work differently and have unique benefits. Here’s a detailed comparison of everything we’ve gone through for each medication:
| Medication | Metformin | Rybelsus® |
|---|---|---|
| Pricing per month (without insurance) | Price ranges from $4 to $20 per month for generic medication. Branded medication costs between $37 and $62. With insurance, costs can be as low as $10 per month, though this is rare for weight loss use. | $998 per month With insurance, copays can be as low as $10 per month, depending on your plan, though this is rare for weight loss use. |
| How it’s taken | IR: 1 tablet usually taken twice per day on a full stomach. ER: 1 tablet taken once per day with your evening meal. | 1 tablet taken on an empty stomach. You’ll need to wait at least 30 minutes before eating, drinking, or taking other medications. |
| Insurance coverage | May be covered for type 2 diabetes, but rarely for weight loss. | Same, but less likely to be covered for type 2 diabetes due to the price. |
| Side effects | Diarrhea, nausea, bloating, and gas | Nausea, vomiting, diarrhea, and stomach pain |
| Effectiveness | Average of 5 to 6% of body weight | Average of 4% of body weight |
Can you take metformin and Rybelsus® together?
Yes, some people take metformin and Rybelsus® together, especially if they have type 2 diabetes or are looking for enhanced weight loss and blood sugar control. Since these medications work differently, combining them can offer additional benefits:
- Metformin helps lower insulin resistance and reduce glucose production in the liver.
- Rybelsus® (semaglutide) slows digestion, reduces appetite, and helps regulate blood sugar by mimicking the GLP-1 hormone.
According to studies, taking these medications together can lead to a significant increase in weight loss compared to using just one. While research is still developing, some studies suggest that combining metformin with a GLP-1 receptor agonist like Rybelsus® leads to a greater reduction in BMI than metformin alone. How you respond will depend on your metabolism, diet, and lifestyle choices.
Rybelsus® and metformin: Alternatives
While Rybelsus® and metformin can help people lose moderate amounts of weight, they may not be the right fit for everyone. There are several alternative medications to think about if weight loss is your primary goal.
GLP-1 receptor agonists
| Medication | Brand names and uses | Cost per month (without insurance) | Effectiveness | How it’s taken |
|---|---|---|---|---|
| Semaglutide – GLP-1 receptor agonist – Same active ingredient as Rybelsus®. | Wegovy®: weight loss and heart disease Ozempic®: type 2 diabetes, off-label weight loss | Wegovy®: $1,350 $499 (NovoCare Pharmacy) Learn more Ozempic®: $998 Learn more | Wegovy®/Ozempic®: People lost an average of 15% of body weight in 68 weeks with injectable semaglutide | Wegovy®/Ozempic®: Weekly injection |
| Liraglutide – GLP-1 receptor agonist | Victoza®: type 2 diabetes, off-label weight loss Saxenda®: weight loss and heart disease Generic liraglutide: type 2 diabetes, off-label weight loss | Victoza®: $800 to $1,400 Learn more. Saxenda®: $1,350 Learn more. Generic liraglutide: $470 – $700 | People lost an average of 5-6% of body weight in one year. | Daily injection |
| Tirzepatide – GLP-1/GIP receptor agonist | Mounjaro®: type 2 diabetes, off-label weight loss Zepbound®: weight loss and obstructive sleep apnea (OSA) | Mounjaro®: $1,080 Learn more Zepbound®: Pens: $1,087 Vials: $349 (2.5 mg) $499 (5 mg, 7.5 mg, 10 mg) Learn more | People lost an average of 21% of body weight at 72 weeks. | Weekly injection |
Other medications
GLP-1s aren’t the only options. These medications work in different ways and can be prescribed to help people lose weight if needed.
| Medication | Brand names | Cost per month (without insurance) | Effectiveness | How it’s taken |
|---|---|---|---|---|
| Phentermine | Lomaira®, Adipex-P® | $27-$100 | About 80% of people with a BMI of 30 or more lost at least 5% of their body weight in 6 months. | Daily pill |
| Diethylpropion | Tenuate®, Tenuate Dospan® | $40-$85 | People lost an average of 10% of their body weight in 6 months. | Pill taken one to three times daily |
| Naltrexone and bupropion | Contrave® | $600-$800 CurAccess™: $99 | People lost an average of 7 to 8% of their body weight in a year. | Pill taken up to twice daily |
| Orlistat | Xenical®, Alli® | $50-$800 | People in a study lost about 10% of body weight after taking Orlistat for 1 year. | Pill taken three times daily with meals. |
Your best option depends on your health goals, budget, and insurance coverage. Whether it’s a GLP-1 medication like Ozempic®, an alternative like tirzepatide, or another weight loss approach, working with a healthcare provider can help you find the best fit for long-term weight management.
Choosing between Rybelsus® and metformin
Choosing between Rybelsus® and metformin comes down to your unique health needs, lifestyle, and long-term goals. Rybelsus® (oral semaglutide) offers the benefits of a GLP-1 receptor agonist, helping regulate blood sugar and support weight loss, while metformin is a well-established, cost-effective option primarily used to improve insulin sensitivity.
That said, while medication can be a valuable tool, lasting weight management requires a broader, sustainable approach that includes nutritional choices, physical activity, and behavioral changes. Whether you’re considering GLP-1 medications, non-GLP-1 alternatives, or other treatment options, the key is finding a plan that works for you and supports long-term success. The good news is that there are more choices than ever, allowing for a personalized approach to weight loss and metabolic health.
No matter which path you take, the foundation of successful weight management lies in building lasting habits. That’s where Noom Med can help—by offering a personalized, science-backed program that complements your medication and guides you toward sustainable lifestyle changes. Whether you’re using Rybelsus, metformin, or another treatment, Noom provides the support you need to take control of your health and feel your best now and in the future.
Note: Rybelsus®, Ozempic®, Mounjaro®, Victoza®, and metformin are not FDA-approved to treat obesity or for weight loss.
