Can Metformin Cause Weight Loss?

If you're managing type 2 diabetes, you may have heard that some medications can also support weight loss. But is this true? And how does it work?

In short, yes - some diabetes medications can support weight loss. For many, the potential for weight loss is the main reason why they choose certain medications. 

In this guide, we explore which diabetes medications are linked to weight loss, why this happens, how long it takes, and what to know if you're worried about weight gain instead.

Key Takeaways

• Some diabetes medications – including Metformin, Ozempic, and Mounjaro – can support weight loss.
• Metformin usually causes modest, steady weight loss or helps maintain your weight over time.
• GLP-1 receptor agonists like Ozempic and Mounjaro typically result in greater weight reduction.
• Some diabetes drugs can cause weight gain.
• Always consult a healthcare professional before changing medication.

Can Diabetes Medication Cause Weight Loss?

Yes, certain diabetes medications can lead to weight loss as a side effect. In fact, in some cases, this is an intended part of the treatment.

Weight loss can improve blood sugar levels and insulin sensitivity, which is why medications like GLP-1 receptor agonists (e.g., Ozempic and Mounjaro) have seen a huge surge in popularity recently in those with type 2 diabetes and obesity. 

GLP-1 receptor agonists work in various ways, helping to: 

• Reduce appetite
• Slow down digestion
• Helping your body use insulin more effectively
• Increasing feelings of fullness

This, in turn, can help you to lose weight whilst also improving blood sugar levels. 

Which Diabetes Medications Can Cause Weight Loss?

Here is a breakdown of the main diabetes drug classes and branded medications linked to weight loss:

1 - GLP-1 Receptor Agonists

GLP-1 receptor agonists are a newer class of type 2 diabetes medications that mimic a naturally occurring hormone called GLP-1 (glucagon-like peptide-1). This hormone is released in the gut in response to food and helps to regulate blood sugar levels, slow digestion, reduce appetite, and make you feel fuller for longer. 

GLP-1 receptor agonists are known to cause significant weight loss in patients with and without type 2 diabetes. 

Some types of GLP-1 receptor agonists include:

• Ozempic (semaglutide) – Works by slowing gastric emptying and reducing appetite. In clinical trials, patients lost an average of 5–10% of their body weight over several months. 

 ➤ Learn more – can semaglutide cause diabetes?

• Wegovy (semaglutide) – Prescribed at a higher dose than Ozempic and has shown even more impressive results, with some patients achieving 15% or more total body weight loss. 

 ➤ Learn more – can semaglutide reverse diabetes?

• Mounjaro (tirzepatide) – A dual GIP and GLP-1 receptor agonist with even higher weight loss outcomes than semaglutide in head-to-head trials. Patients report weight loss of up to 22.5% of their body weight. 

 ➤ Learn more – can Mounjaro cause diabetes?

• Trulicity (dulaglutide) – Although this is not as potent as semaglutide or tirzepatide, it is often well-tolerated and used as a long-term diabetes management option.

• Victoza (liraglutide) – Victoza was one of the earlier GLP-1 agonists approved for type 2 diabetes and has been shown to help with weight loss as well. This is also sold as Saxenda on a higher dose, approved for weight management. 

GLP-1 receptor agonists are some of the most effective diabetes medications for weight loss, especially when combined with lifestyle changes. You typically take these once a day or once a week. 

We can determine the best weight loss treatment for you based on your health history and goals – complete a simple assessment today to get started! 

2 - SGLT2 Inhibitors

SGLT2 inhibitors, also called gliflozins, work by blocking a protein in the kidneys known as sodium-glucose co-transporter 2 (SGLT2), which normally reabsorbs most of the glucose filtered through the kidneys. This helps the body remove excess glucose through urine, lowering blood sugar levels without relying on insulin.

Although effective for diabetes management, these medications don't usually lead to as much weight loss as GLP-1 drugs. 

Examples include:

• Jardiance (empagliflozin)
• Forxiga (dapagliflozin)
• Invokana (canagliflozin)

3 - Biguanides

This is one of the oldest and most prescribed diabetes drug classes. Biguanides help to reduce glucose production in the liver and improve insulin sensitivity.

Metformin (sold under the brand name Glucophage) is the most prescribed medication for type 2 diabetes. It is associated with mild weight loss or weight neutrality, making it a good choice if you have type 2 diabetes and you're concerned about weight gain.

Metformin lowers glucose production in the liver and improves insulin sensitivity. It may also reduce appetite and alter gut microbiota in ways that favour lower calorie intake. Unlike insulin-increasing drugs, Metformin does not promote fat storage. 

Instead, Metformin often produces modest weight loss. On average, patients may lose around 2–7 lbs (1–3 kg) over several months. 

Metformin is a good option for people with type 2 diabetes who:

• Want to avoid weight gain, have insulin resistance or prediabetes
• Prefer an oral, low-cost medication with an established safety record 

It’s often used as first-line therapy and can be combined with other drugs for additional effect.

Can Diabetes Medications Cause Weight Gain?

Yes, not all diabetes medications lead to weight loss. In fact, some treatments are associated with weight gain, especially older drugs or those that work by increasing insulin levels in the body. 

Some diabetes medications that may lead to weight gain include:

• Sulfonylureas – such as gliclazide, glibenclamide, glipizide and glyburide
• Thiazolidinediones (TZDs) – such as pioglitazone and rosiglitazone
• Insulin – While essential for many, insulin therapy is associated  with increased appetite and fat storage but is not necessarily the direct cause

Why?

Certain diabetes medications stimulate the body to produce more insulin or supply insulin directly. Although insulin is essential for controlling blood sugar, it also promotes the storage of glucose in fat cells. This can lead to:

• Increased appetite
• Fat accumulation
• Trouble losing weight

Some diabetes medications may also cause water retention or low blood sugar (hypoglycaemia). This may trigger overeating and contribute further to weight gain.

How Long Does It Take to Lose Weight on Diabetes Medication?

Weight loss results can vary – however, many people begin noticing weight loss after just a few weeks of taking GLP-1 medications such as Mounjaro and Wegovy.

When taking Wegovy, for example, you may begin to notice significant weight loss by month 3. Participants in a clinical trial lost between 5-10% of their starting weight by month 3. Learn more about the Wegovy weight loss timeline here. 

On average:

• On GLP-1 receptor agonists, you may lose 5–15% of your total body weight loss over several months
• On Metformin, you may lose 2–7 lbs, typically over a longer period
• SGLT2 inhibitors may lead to more modest weight loss of around 4-5 lbs

Looking to explore weight loss solutions with expert guidance? Book a consultation with Dr Frank’s Weight Loss Clinic today.

Diabetes Medication & Weight Loss FAQs