From the Guidelines
Metformin is associated with approximately 3% weight loss, and approximately 25% to 50% of participants achieve at least 5% weight loss, making it a viable option for weight management. Metformin (a biguanide oral hypoglycemic medication) typically leads to weight loss of about 2-3 kg (4.4-6.6 pounds) over time, though individual results vary 1. This effect is one reason metformin is sometimes prescribed off-label for weight management, particularly in patients with insulin resistance or prediabetes. The weight loss occurs through several mechanisms: metformin reduces appetite by affecting hunger hormones, decreases intestinal absorption of carbohydrates, improves insulin sensitivity which reduces fat storage, and may increase calorie expenditure 1.
Some key points to consider when using metformin for weight loss include:
- Doses of metformin greater than 1500 mg are associated with the greatest weight loss 1
- Metformin’s pleiotropic effects include decreased inflammation, increased insulin and leptin sensitivity, and decreased hunger and ghrelin levels, especially with twice-daily dosing 1
- Metformin is widely available and inexpensive, making it a cost-effective option for weight management 1
- The weight loss effect is usually gradual and most noticeable during the first 6 months of treatment 1
It's worth noting that while metformin has been shown to be effective in reducing weight, it is not FDA approved for this indication 1. However, based on the available evidence, metformin can be a useful adjunct to lifestyle modifications for weight loss, particularly in patients with insulin resistance or prediabetes 1.
From the FDA Drug Label
Mean change in body weight from baseline to week 29 was 0.9 lbs, -0.7 lbs, and -8.4 lbs in the metformin hydrochloride tablets /glyburide, glyburide, and metformin hydrochloride tablets arms, respectively. Mean change in body weight from baseline to week 16 was -3.3 lbs and -2.0 lbs in the metformin hydrochloride tablets and placebo arms, respectively. Mean change in body weight from baseline to week 24 was 0.9 lbs, 1.1 lbs and 0.9 lbs, respectively.
Metformin can cause weight loss. The studies show that patients taking metformin had a mean change in body weight ranging from -8.4 lbs to -2.0 lbs compared to baseline, while some studies showed minimal weight gain (0.9 lbs and 1.1 lbs) 2.
From the Research
Metformin and Weight Loss
- Metformin, a biguanide oral hypoglycemic, has been found to cause weight loss in several studies 3, 4, 5, 6, 7.
- The mechanisms by which metformin induces weight loss are multifactorial, including decreased appetite, changes in hypothalamic physiology, and alterations in gastrointestinal physiology and circadian rhythm 3, 4.
- Studies have shown that metformin produces durable weight loss, with decreased food intake being the primary weight loss mechanism 3, 7.
- Metformin has been found to induce modest weight loss in overweight and obese individuals at risk for diabetes, with a mean maximum weight loss of 8 kg greater than that of the placebo group in one study 6.
- The weight loss associated with metformin is related to adherence to the medication, with greater weight loss observed in individuals who take the medication as prescribed 7.
Key Findings
- Metformin decreases food consumption and induces weight loss in subjects with obesity with type II non-insulin-dependent diabetes 6.
- Metformin produces weight loss and delayed or prevented diabetes in the Diabetes Prevention Program (DPP) 7.
- The long-term safety and tolerability of metformin, along with its associated weight loss, have been established in several studies 5, 7.
- Metformin's effects on weight loss are not limited to individuals with diabetes, as it has also been found to induce weight loss in obese non-diabetic populations 5.