What is metformin?
Metformin is a drug designed for treatment for people with type 2 diabetes (T2D). It can also be used to prevent diabetes in people who are pre-diabetic (1). Metformin is a popular medication basically because it works, there are few side effects and the cost is relatively low.
Besides diabetes, metformin has also been shown to possibly have benefit for polycystic ovary syndrome (PCOS). The exact cause for PCOS is not known, and it is a hormonal imbalance in women that may include menstrual irregularity, cysts on ovaries and excess androgen hormones.
A common side effect from taking metformin is weight loss. Weight loss is usually desired for lowering risk for T2D which is a reason metformin works for lowering risk and managing T2D.
Because weight loss can be a result for taking metformin, can anyone take metformin for weight loss?
Is metformin safe for weight loss? Some, but not all, studies have shown metformin to be a safe treatment for weight loss for people who are obese. However, taking metformin may not be best for everyone, especially those that do not have a significant amount of weight to lose.
Consulting your healthcare provider before taking any medication is recommended.
How does metformin work?
Metformin emerged as an anti-diabetic drug in the 1950’s and continues to be a common prescription for managing or preventing T2D.
One of the main ways metformin works is by reducing insulin resistance (2). Insulin resistance is the main contributor for T2D and can also be a contributor for PCOS.
While the exact mechanisms metformin helps with weight loss are still being clarified, it is thought metformin contributes to weight loss at least in part because it increases insulin sensitivity (3).
Metformin lowers the amount of glucose produced by the liver, lowers the absorption of glucose from the intestine and helps to increase muscle uptake of glucose (4).
Metformin is used as an insulin sensitizing drug not as a primary weight loss medication. Weight loss is a side effect based on how metformin works in the body.
Does metformin help with weight loss?
A 2012 study (5) examined metformin’s safety and tolerability for weight loss in participants of the Diabetes Prevention Program (DPP). No safety issues were noted, although some gastrointestinal side effects were noted in the group receiving metformin compared to the placebo group.
Metformin participants had lower body weight and waist circumference compared to the placebo group.
Participants went through a two year double blind period either on metformin or a placebo. After 2 years, it was an unblinded study, and metformin group continued to lose more weight than people in the placebo group.
Researchers concluded metformin is a safe treatment for diabetes prevention and durable for up to 10 years according to this study.
Other studies (6) found metformin alone decreased calorie intake but not percent body fat, and metformin plus exercise was also shone to decrease body weight more than exercise alone.
However, not all studies have found a significant weight loss with metformin. Some studies also suggest weight loss with metformin is not a quick process; it may take a year or two to notice significant weight loss from metformin and can vary.
Should you take metformin if you don’t have diabetes?
Metformin was designed to help regulate blood sugar levels in those with T2D or pre-diabetes.
Should you take metformin for weight loss if you don’t have blood sugar issues? A 2013 study (7) analyzed weight loss in obese participants with and without insulin resistance.
Metformin increased weight loss in both insulin sensitive and insulin resistant individuals.
However, people who had more insulin resistance lost significantly more weight than those who were insulin sensitive.
Researchers concluded metformin can be effective for weight loss in both insulin sensitive and resistant individuals.
However, other studies have not shown a significant benefit of metformin for weight loss in non-diabetic participants. Therefore, more research is needed on metformin’s effect on weight loss.
One thing is for sure no matter what approach you use for weight loss when taking a drug or supplement. No matter what a supplement/drug may claim, you can’t eat whatever you want and still expect weight loss.
Metformin and other drugs for weight loss need to be in conjunction with a healthy diet and active lifestyle.
If you have further questions about if metformin can help with your weight loss, speak with your healthcare team before taking. Individual results may vary for weight loss while on metformin, and weight gain may happen after you stop taking it.
Conclusion: Is metformin safe for weight loss?
Studies to date do not suggest meformin is unsafe. It is likely safe for most people, possibly up to 10 years. Even though it is considered safe, some may experience temporary gastrointestinal or other side effects when on metformin.
Metformin is a drug for diabetes prevention and management first and foremost; it is not currently considered only a weight loss drug. Weight loss is a side effect from metformin, and more research is needed for using metformin for a weight loss drug.
Some studies suggest metformin can have a side effect of weight loss when it is taken along with a healthy diet.
It may help encourage weight loss when other lifestyle habits are in place that also promotes weight loss.
Taking metformin alone, without any other lifestyle changes, may not lead to weight loss or other health benefits. The bottom line is Metformin is not a magic bullet pill for weight loss.