From the Guidelines
Metformin should be prescribed at a dose of 500-2000 mg per day for weight loss, starting with a low dose of 500 mg once or twice daily with meals and gradually increasing to minimize gastrointestinal side effects. According to the most recent and highest quality study 1, metformin is effective and safe for glucose lowering, and its use for weight loss should be under strict medical supervision. The medication works by reducing glucose production in the liver and improving insulin sensitivity, which can lead to modest weight loss of 2-3% body weight over time.
Key Considerations
- The dose of metformin can be titrated up to 1000-2000 mg per day divided into two doses to achieve optimal weight loss while minimizing side effects 1.
- Common side effects of metformin include nausea, diarrhea, and abdominal discomfort, which often improve with time 1.
- Patients should combine metformin use with a balanced diet and regular exercise for optimal results.
- Regular monitoring by a healthcare provider is essential to assess effectiveness and adjust dosage as needed.
Important Safety Information
- Metformin may cause lactic acidosis, a rare but serious complication, especially in patients with kidney disease or acute kidney injury 1.
- The risk of lactic acidosis can be mitigated by using the extended-release formulation and gradual dose titration.
- Patients with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m² should not use metformin due to the increased risk of lactic acidosis 1.
Clinical Decision Making
- The use of metformin for weight loss should be individualized and based on a thorough assessment of the patient's medical history, current medications, and potential risks and benefits.
- Healthcare providers should closely monitor patients for signs of lactic acidosis, vitamin B12 deficiency, and worsening neuropathy symptoms, and adjust the metformin dose or discontinue use as needed 1.
From the FDA Drug Label
2 DOSAGE AND ADMINISTRATION
- 1 Adult Dosage Metformin Hydrochloride Tablets The recommended starting dose of metformin hydrochloride tablets are 500 mg orally twice a day or 850 mg once a day, given with meals. Increase the dose in increments of 500 mg weekly or 850 mg every 2 weeks on the basis of glycemic control and tolerability, up to a maximum dose of 2550 mg per day, given in divided doses.
The FDA drug label does not answer the question.
From the Research
Metformin Dose for Weight Loss
- The dose of metformin for weight loss is not explicitly stated in the provided studies, but the following doses were used in the studies:
- It is worth noting that metformin is typically used to treat type 2 diabetes, and the dose for weight loss may be different from the dose used to treat diabetes.
Efficacy of Metformin for Weight Loss
- Metformin has been shown to be effective for weight loss in non-diabetic individuals with obesity, with a mean weight loss of 5.8 ± 7.0 kg (5.6 ± 6.5%) over 6 months 2
- Patients with severe insulin resistance lost significantly more weight than insulin-sensitive patients 2
- Metformin XR (extended-release metformin) has been shown to be effective for weight loss, with a significant reduction in body weight compared to placebo 6