Metformin Dosage For Weight Loss Without Diabetes: Understanding The Approach 2024

The United States is facing a growing problem. Over the last 60 years, the rates of obesity have tripled,^[1] and an estimated two-thirds of adults^[2] are considered overweight. This has also led to considerable interest in weight loss strategies ranging from a healthy diet to detox water and over-the-counter supplements. 

More recently, diabetes medications have been linked to body weight management. For example, semaglutide,^[3] the active ingredient in Ozempic and Wegovy, has been associated with significant weight loss. These results have also been observed in non-diabetic individuals.

Metformin is also a medication used for diabetes that has been associated with weight loss^[4] beyond people with diabetes. So, is metformin effective for weight loss and safe to use for individuals who do not have diabetes? If so, what is the ideal metformin dosage for weight loss without diabetes? 

Metformin Dosage For Weight Loss Without Diabetes

The doses of metformin treatment vary, but higher doses have been associated with a somewhat higher likelihood of weight loss. In a recent review article that compiled data from multiple studies, the results related to weight loss were mixed.^[5] The doses used were broken down in the following way: 

• Less than 1,500 mg per day: Lower doses were used more commonly by study participants who were under the age of 18. A dose of 1,000 mg was associated with an average weight loss of about 0.88 units of BMI, or body mass index.
• More than 1,500 mg per day: Higher doses were targeted more frequently among adults who were identified as obese patients and in people managing polycystic ovary syndrome, or PCOS. Doses reaching 1,700 mg to 2,500 mg resulted in a slightly higher weight loss of about 1.01 units of BMI.

Lower doses of metformin are sometimes used by people who have difficulty tolerating gastrointestinal side effects like upset stomach, nausea, or diarrhea. 

Studies Evaluating Metformin And Weight Loss

Metformin^[6] is believed to help with weight loss by decreasing carbohydrate absorption, reducing glucose production in the liver, and helping suppress appetite. It does appear weight loss may be partly dependent on insulin sensitivity. 

Diabetes Risk

A study has compared weight loss with metformin in an obese population who were either insulin-sensitive or insulin-resistant. The weight loss effect^[7] appeared to be higher among participants with insulin resistance, suggesting more benefits among individuals at risk for diabetes. In this study, when an average dose of 2,230 mg of metformin was given, an average weight loss of 5.8 kg or 12.8 pounds was observed. 

When metformin has been evaluated for individuals at risk for developing diabetes,^[8] its outcomes have been positive. Metformin reduced diabetes development by 31% and was associated with an average weight loss of 2.5 kg or 5.5 pounds over time. 

Medication-Induced Weight Gain

There has also been some research related to weight gain associated with medications used to support mental health. Metformin has been evaluated^[9] for the prevention of antipsychotic-induced weight gain and has demonstrated promising results. More data is needed to confirm the results, but on average, metformin was associated with a weight loss of about 4 kg or 8.8 pounds. 

Polycystic Ovarian Syndrome

In a review of twelve clinical trials^[10] of metformin in women managing PCOS, an average reduction in BMI of about 1.25 units was observed. While the effects on weight loss were somewhat modest, there were also improvements in testosterone levels, menstrual cycle regularity, and other symptoms. Metformin has been commonly recommended^[11] for PCOS management for decades because of these potential benefits. 

Further studies related to specific populations can help determine who may be more likely to benefit from metformin therapy. A primary concern is whether metformin reliably produces clinically significant weight loss,^[12] which is more predictive for beneficial effects like lowering the risk of cardiovascular disease. 

Metformin And Clinically Significant Weight Loss

When medications are evaluated for their potential weight loss benefits, a standard goal of therapy is a weight reduction of 5% from baseline levels prior to therapy. This is because moderate weight loss of 5% to 10%^[12] of initial body weight is associated with benefits that may outweigh any potential risks of therapy. 

Because of the variability observed among trials, understanding whether metformin will reliably provide significant weight loss is important. While some individuals have achieved more weight loss, people had an average reduction of about one unit^[5] of BMI. This is not enough information to determine if people lost more than 5% of their baseline weight. 

Benefits Of Clinically Significant Weight Loss

When weight loss of 5% to 10% of baseline body weight is achieved, it has been associated with:^[12] 

• Improved self-image.
• Lower blood glucose levels and lower rates of diabetes.
• Lower risk of cardiovascular disease.
• Lower risk of developing sleep apnea.
• Less knee pain and improved mobility.

When considering metformin or lifestyle intervention, it is important to note that diet and lifestyle changes will likely improve weight loss efforts with or without medication. Tracking overall calorie and carbohydrate intake, staying hydrated, and staying physically active will help build habits that support sustainable weight loss over time. Losing weight without exercise is certainly possible, but it can be more difficult. 

Risks Of Metformin Therapy

Whether you decide to start medication ultimately relies on evaluating whether the benefits of therapy are likely to outweigh the potential risks. Because both the benefits and risks of therapy can vary between individuals, consult with your doctor and ensure that they have a complete and accurate medical history.

Side Effects

Metformin^[13] is generally well-tolerated. The most common side effects are gastrointestinal: 

• Upset stomach.
• Nausea and vomiting.
• Diarrhea.

Using extended-release metformin tablets can lessen the impact of these side effects. It is also helpful to slowly increase the metformin dose over time and take the medication with food. 

Metformin’s effect^[13] on blood sugar is primarily related to helping your body’s existing insulin work more efficiently. It’s unlikely for your blood sugars to drop to dangerous levels. Hypoglycemia is more of a concern if you also use other glucose-modifying medications like insulin or sulfonylureas such as glipizide or glimepiride. 

Precautions

Metformin has been associated with an increased risk of lactic acidosis.^[13] This is a metabolic imbalance that can become severe enough to require hospitalization and has been fatal in some cases. The risk of developing lactic acidosis is higher for individuals with:

• Reduced liver function.
• Reduced kidney function.
• A history of alcohol abuse.
• An age of 65 or older.

When metformin is started, kidney and liver function should be measured and monitored periodically during therapy. 

Individuals with a history of B12 deficiency should exercise caution when considering therapy with metformin. Metformin has been associated with decreases in vitamin B12 levels.^[14] If B12 levels drop too low, it can cause anemia, which can leave you feeling exhausted or make it difficult to catch your breath. 

How To Take Metformin For Weight Loss Without Diabetes

Metformin is not approved for weight loss or people without diabetes. Using metformin for weight loss is considered an off-label use, which your doctor may deem appropriate depending on your individual needs. Consulting your doctor will help determine whether metformin is an appropriate option. 

The standard approach to taking metformin does not change specifically for weight management. Especially early in therapy, a primary goal is to avoid or limit gastrointestinal side effects. This can be accomplished by:

• Increasing the dose of metformin slowly over time.
• Taking metformin with meals.
• Using metformin extended-release tablets.

The dose is often split into two doses over the course of the day, so most individuals will take a dose with breakfast and another with supper. 

Can Metformin Help You Lose Weight Quickly?

While many individuals set out to lose weight quickly, it is important to ensure you are maintaining a healthy balance. Paying close attention to total calories and net carbohydrates can be beneficial, but it is equally important to ensure you are getting enough nutrients. 

Work with your doctor or a licensed dietitian to help you maintain your intake of essential nutrients and monitor for any signs of deficits. A healthy rate of weight loss of about one to two pounds each week is less likely to produce nutritional imbalances and is more sustainable over time. Weight loss benefits have been evaluated after a period of six months.^[7] 

Conclusion

With the recent surge of interest in using diabetes medications for weight loss, metformin has emerged as a treatment option. Metformin is generally well-tolerated and has been a cornerstone in diabetes management over time. 

Metformin is not approved for weight loss or for individuals who do not have diabetes. However, some studies have evaluated weight loss benefits for individuals who do not have diabetes. 

The results of the studies have been somewhat mixed. Because of this, more studies with specific patient groups are needed to determine the benefit of using metformin for weight loss. The strongest evidence in favor of choosing metformin for weight loss is for individuals who are at risk for developing diabetes or who are managing PCOS. 

Treatment decisions need to be individualized, and your doctor can help you determine whether metformin is likely to be safe and effective for your unique needs.