Metformin for Weight Loss: How long it takes to lose weight on Metformin

Key takeaways:

• Metformin, a widely used diabetes medication, is occasionally prescribed by doctors for weight loss. It can help achieve significant weight loss and prevent further weight gain.
• It can take a few weeks to several months to lose weight on metformin
• Alternatives to metformin for weight loss include semaglutide (Ozempic), beinaglutide, and orlistat (Xenical).
• However, metformin should not replace a healthy diet and regular exercise. Consult your doctor to explore the most effective weight loss methods.

Metformin is one of the most popular medications used for managing diabetes. It is an anti-diabetic in the Biguanide class.

Metformin reduces blood glucose levels by reducing the absorption of glucose from food and the production of glucose by the liver. Also, it increases the body’s sensitivity to insulin, a hormone responsible for managing blood glucose levels naturally.

Does metformin (Glucophage) work for weight loss?

The role of metformin in weight loss is secondary. Metformin was not initially intended for use as a weight-loss medication but rather for treating type 2 diabetes. 

However, some research, such as a study that was conducted on the long-term weight loss associated with metformin, showed that metformin significantly decreased body weight and waist circumference with few concerns and minimal tolerability issues.

Even though metformin is not a medication that was primarily designed to be used for weight loss, neither has it been approved for weight loss officially, studies have proven it to be effective in weight reduction.

Some other studies have also indicated that this medication is a favorable weight-loss option for people who are overweight and have an increased risk of developing diabetes.  

Metformin is not a magic pill for weight loss and should be used as a part of a broader weight management plan. It is important to note that weight loss achieved with metformin can be maintained for up to 10 years, but only if the medication is consistently taken as prescribed.

The mechanisms by which metformin works for weight loss include:

• Reducing the liver’s production of glucose. This reduction in glucose production helps lower blood sugar levels and reduces the amount of sugar available to be stored as fat.
• Increasing insulin sensitivity. This means that glucose can be more effectively taken up by the cells and used for energy rather than being stored as fat.
• Decreasing intestinal absorption of glucose. This helps prevent high blood sugar levels and reduces the amount of glucose that can be converted into fat.

How long it takes to lose weight on metformin

The timeline for weight loss with metformin can vary significantly from person to person. Some people on metformin may start to see weight loss within a few weeks, while for others, it might take several months.

For individuals with diabetes, it may take them a longer time to lose weight using metformin. According to the United Kingdom Prospective Diabetes Study (UKPDS), patients with diabetes experienced an average weight loss of 2.7 kg over 4 years.

Individuals without diabetes had an average weight loss of 2.1 kg over three years. Also, individuals who adhered to their medications strictly had a 3.5% reduction in body mass over two years. This was according to the Diabetes Prevention Program (DPP).

Metformin should be combined with lifestyle changes such as diet and exercise for the best results.

Who may use metformin for weight loss?

Metformin may be prescribed for weight loss in the following groups of people:

• Individuals with type 2 diabetes: Metformin is an anti-diabetes medication that is used to reduce blood sugar levels and can reduce the body mass index of these patients.
• People with insulin resistance: Metformin increases the body’s sensitivity to insulin, and people with insulin resistance may benefit from metformin’s effects as a weight loss medication.
• People with polycystic ovary syndrome (PCOS): Polycystic ovary syndrome often leads to insulin resistance. Metformin can help manage the metabolic, ovulation, and weight issues associated with PCOS.
• Individuals at risk for diabetes: Sometimes, metformin is prescribed to those with prediabetes to prevent the progression to type 2 diabetes and aid in weight management.
• Individuals on antipsychotic medications: Metformin can be used as an off-label drug in patients who are on antipsychotic medications, as most of these medications are known to cause weight gain and other metabolic complications.

Who can’t take metformin for weight loss?

Certain individuals should avoid taking metformin for weight loss. They include:

• People with kidney problems: Metformin is processed through the kidneys, and impaired kidney function can lead to a dangerous buildup of the medication in the body. This can, in turn, lead to a rare but serious condition: lactic acidosis (a medical condition where too much lactic acid builds up in the body, causing an imbalance in the body's pH levels).
• Individuals with liver disease: Since the liver plays a role in drug metabolism, liver disease can affect how metformin is processed.
• Pregnant or breastfeeding women: The safety of metformin for weight loss in pregnant and breastfeeding people has not been well established. Therefore, it is not advisable for weight loss purposes during pregnancy.
• People whose diabetes is uncontrolled: Persistently high blood sugar levels can increase the risk of complications when using metformin for weight loss.
• People with alcohol use disorder: People who consume excess alcohol should not take metformin for weight loss because alcohol affects liver function and can worsen the side effects of metformin.
• People with cardiovascular and respiratory issues: Taking metformin for weight loss may also not be ideal for people who have recently had a heart attack, and those who have severe problems with circulation or breathing difficulties.

Metformin dosage for weight loss

The typical starting dose of metformin for weight loss in adults is 500 mg taken once or twice daily, with potential gradual increases to 1500–2000 mg once daily, depending on tolerance and response. 

It is important to follow a healthcare provider's instructions and personalized dosage and not to adjust the dosage without medical advice, as improper use can lead to adverse effects.

Alternatives to metformin for weight loss

While metformin may cause weight loss in some people, it was not originally designed for that purpose. Some better medications and alternatives are more effective than metformin for weight loss.

Other weight-loss medications

• Beinaglutide: This is a short-acting glucagon-like peptide 1 receptor agonist (GLP-1RA) with 100% similarity to human GLP-1 (a hormone that helps regulate blood sugar and control appetite). Beinaglutide mimics natural GLP-1’s effects by suppressing appetite, thereby reducing food intake and slowing stomach emptying.
• Semaglutide (Ozempic, Wegovy): Semaglutide is a GLP-1 receptor agonist that helps regulate appetite and calorie intake, often leading to significant weight loss.
• Tirzepatide (Mounjaro): Tirzepatide imitates the hormones glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 to target brain regions that control appetite and food consumption. It has shown promising results in promoting weight loss in clinical trials.
• Orlistat (Xenical): Orlistat works by inhibiting pancreatic lipase, an enzyme necessary for the breakdown of dietary fats in the intestine. Orlistat prevents fat consumed in a meal from being digested, leading to reduced calorie intake and weight loss.

Lifestyle and dietary strategies that support weight loss

• Dietary Changes: Adopting a balanced diet rich in fruits, vegetables, lean proteins, and whole grains can support weight loss. Reducing refined sugars and unhealthy fats is also often beneficial for weight management.
• Regular Exercise: Engaging in regular physical activity, such as aerobic exercises and strength training, can enhance weight loss and improve overall health.
• Behavioral Therapy: Cognitive-behavioral therapy (CBT), a type of therapy that helps people change negative thoughts about themselves and the world to improve unwanted behaviors; and other behavioral interventions can help modify eating habits and address emotional triggers for overeating.
• Intermittent Fasting: A lot of people have employed this method, which involves cycling between periods of eating and fasting, for weight loss and found success with it.

Questions to Ask Your Doctor Before Taking Metformin for Weight Loss

Before starting metformin for weight loss, consider asking your doctor the following questions:

1. Is metformin appropriate for my specific health condition and weight loss goals?
2. What are the potential side effects of metformin, and how can they be managed?
3. How long should I take metformin to see if it is effective for weight loss?
4. Are there any dietary or lifestyle changes I should make while taking metformin?
5. How will my progress be monitored while I am on metformin?
6. What are the signs that I should stop taking metformin and seek medical attention?