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Metformin vs. Mounjaro for Weight Loss

<p>Metformin vs. Mounjaro for Weight Loss</p>
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 8 min read

Many people who struggle to lose weight have seen the great potential diabetes drugs hold for weight loss and management. The media are touting the massive benefits of drugs like Metformin and Mounjaro for weight loss. Although these drugs are traditionally used to treat type 2 diabetes, they have the added benefit of weight loss.


Metformin is typically the first medication doctors prescribe to treat type 2 diabetes, according to the Mayo Clinic. Metformin comes in tablet form and is very effective in treating diabetes. However, its added benefit of weight loss has made it quite popular to a mainstream audience. Metformin is the first medication in its class that was FDA-approved to facilitate weight loss and weight management.   

Like many other diabetes drugs, Metformin is most effective when it is combined with exercise and a healthy diet. Foods that can be included in a healthy diet include lean meats, such as fish, fruits, and vegetables. 

Large clinical trials on Metformin have found that adults who took Metformin lost, on average, nearly 15 percent of their starting body weight. Those who did not take Metformin lost significantly less. Metformin has many benefits, including its ability to reduce your A1C. Metformin lowers A1C levels by 1.5 percent when taken at its maximum dosage.     

Studies have also found that Metformin lowers blood sugar levels by 25 percent in individuals with type 2 diabetes. Metformin can also encourage weight loss in individuals with metabolic syndrome. After one year, those taking Metformin for weight loss typically lose an average of six pounds.  

But how does Metformin work exactly? Metformin lowers the amount of glucose your liver releases. It also helps the muscles use glucose more efficiently. This improves insulin sensitivity. Scientists do not fully understand how they work together, but experts have come up with a few theories to explain it.

Metformin affects hunger by suppressing appetite. This makes it easier to lose weight and accelerates the weight loss process.  

In addition to effectively treating diabetes, studies have found that Metformin can prevent or delay the onset of diabetes. Metformin effectively facilitates weight loss. One study followed 12 women who were obese and had diabetes, and found that women who increased their dose by 1,000 or more milligrams lost substantially more weight than those who stayed on the same starting dose.  

According to WebMD, Metformin works by changing the natural balance of bacteria in your digestive system. It also stimulates enzymes that accelerate the body’s use of fat. Because of this, fat is used more efficiently. Because Metformin changes bacteria in your digestive system, it produces digestive side effects. 

Initially, people thought you lost weight on Metformin due to diarrhea or stomach upset. However, that is not always the case. Metformin lowers the body’s resistance to leptin and consequently makes you feel full for an extended period of time. Because you are not as hungry, you don’t eat as much. The result is a decreased appetite, and in many cases, a lower number on the scale.


But what about Mounjaro? How does that differ? According to experts, Mounjaro is an injectable medication that is dispensed once per week. It works to regulate blood sugar levels. However, it has also been found effective in facilitating weight loss. Mounjaro helps you lose weight by slowing the rate at which your digestive system processes and eliminates food. This impacts the amount of food you eat. 

Also known as Tirzepatide, Mounjaro lowers blood sugar, which facilitates weight loss in several ways. First of all, it slows the movement of food through your system, which promotes feelings of fullness. While Mounjaro promotes weight loss in those with diabetes, it has been proven effective in facilitating weight loss in individuals with obesity. 

The FDA has given Tirzepatide the green light, and it is poised for quick approval. Tirzepatide has been given a Fast Track designation, meaning that it will move quickly through the approval process. Mounjaro is used primarily to treat type 2 diabetes, but it has quickly gained attention as a weight loss aid. 

Mounjaro is actually the combination of two different classes of drugs—a glucagon-like peptide-1 and a glucose-dependent insulinotropic polypeptide (GIP) receptor agonist (dual GLP-1/ GIP receptor agonist). According to GoodRX, GLP-1 and GIP are incretin hormones. These hormones are dispersed after you eat. When this happens, the pancreas is triggered to “release insulin.” This tells the liver to decrease the amount of glucose it is currently making. 

As a result, your digestion slows, and your blood sugar is lowered. Mounjaro slows your digestive process, so food moves more slowly through your system. Mounjaro sends signals to your brain, telling it that you are full. Although Tirzepatide has not been approved specifically for weight loss, weight loss is a welcome side effect of this medication. 

Some healthcare providers will prescribe Mounjaro off-label to facilitate weight loss in individuals without diabetes. However, the FDA has not yet confirmed the drug’s safety. Speak with your doctor about taking Mounjaro as a weight loss aid. He or she will be able to prescribe an alternate medication that may be safer for your situation.

Remember that not every medication is going to be a good fit. Many people have preexisting conditions that may be affected by certain medications. That is why it’s so important to seek your doctor’s advice before you take a new medication like Mounjaro. Mounjaro begins to work as soon as you take your first dose. However, it can take weeks to months for you to see a significant change in your blood glucose levels.

In terms of weight loss, both Metformin and Mounjaro have received comparable ratings. Mounjaro is rated slightly lower than Metformin in its effectiveness. But which one is superior, or is there a difference? According to experts, cost is often a consideration. If you are looking for a more cost-effective option, Metformin may be the best option for you. Mounjaro is a lot more expensive than Metformin. 

However, Mounjaro is also much more effective in promoting weight loss than Metformin, according to SugarMD. Mounjaro is one of the most powerful diabetes drugs on the market and helps many people lose weight. 

While Mounjaro has many benefits, Metformin has positive side effects that Mounjaro does not. Experts have found that Metformin reduces your chances of dying from a cardiovascular event.

Experts have found that Metformin may fight aging as well. Metformin is sometimes prescribed off-label to treat conditions, such as gestational diabetes, polycystic ovary syndrome (PCOS), and prediabetes. Prediabetes is a condition in which one’s blood sugar is not elevated enough for them to be diagnosed as diabetic.  

If you have prediabetes, your body may have already sustained damage to the heart, kidneys, and blood vessels. The damage may just be beginning. Having prediabetes doesn’t necessarily mean that you are going to develop diabetes. However, the potential to develop diabetes is there. 

Metformin has a rating of 6.9 on This rating was established through reviews posted by 627 individuals. Both Metformin and Mounjaro can be taken in tandem. If you are considering taking them at the same time, it is important to be aware of drug interactions with Metformin and Mounjaro.   There are 357 drugs that interact with Metformin. These include drugs, such as Lantus or insulin glargine, fish oil, Cymbalta, and Jardiance.

Metformin also has one possible food interaction. You can take Metformin with meals. However, you should limit your alcohol intake or eliminate it from your diet completely. Drinking alcohol while on Metformin can increase your chances of developing a rare but serious side effect called lactic acidosis. Lactic acidosis is a condition in which your body’s production of lactic acid is higher than it should be. 

Mounjaro, on the other hand, comes with a number of gastrointestinal side effects, such as stomach pain, diarrhea, and nausea. These can be managed, of course, but it’s important that both of these drugs have benefits and drawbacks. 

Mounjaro can cause you to feel tired, cause vision changes, and can change your output of urine. You can also develop signs of kidney problems. Signs of kidney problems include the following:

  • Loss of appetite

  • Weakness and fatigue

  • Decreased mental acuity

  • Muscle cramps

  • Dry, itchy skin

  • High blood pressure that is hard to control

  • Chest pain

  • Fluid buildup around the heart

It’s important to remember that not everyone will develop these side effects, but they are something to be aware of, especially if you plan on taking the drug. Ideally, you should find the drug that is best for you. 

Benefits exclusive to Metformin include:

  • Increased cardiovascular health

  • The prevention of cancer

Benefits of Mounjaro include the following:

  • Increased weight loss effectiveness

  • Lower blood glucose levels after meals

Determining which of these medications is best for you will depend on your individual situation. The best way to make the right decision is to do your research, and seek the advice of a medical professional. 



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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.