Metformin, one of the most commonly prescribed diabetes drugs in the world, is most often prescribed for people who live with type 2 diabetes, are overweight or obese, or who have type 1 diabetes but are experiencing severe insulin resistance.
But more and more, people are taking Metformin off-label for the treatment of prediabetes.
Prediabetes is essentially the condition of insulin resistance and resulting high blood sugar levels (HbA1c levels of between 5.7-6.4%), but blood sugar levels that aren’t quite high enough to merit a diabetes diagnosis.
Without intervention, many people with prediabetes will go on to develop type 2 diabetes within 5 years, but early intervention with diet, exercise, and some believe Metformin, may prevent that from happening.
But is Metformin safe? Is it effective? This article will explore the pros and cons of taking Metformin if you have prediabetes.
What is Metformin?
Metformin, often sold under the brand names Glucophage, Glumetza, Glucophage XR, Riomet, or Fortamet, has been studied extensively and was first discovered in 1922.
It was approved by the Food and Drug Administration (FDA) and introduced to the market in the United States in 1995, and is on the World Health Organization’s List of Essential Medicines.
It is a prescription drug used to treat and manage diabetes by lowering blood sugar levels. It is taken orally as a pill and is in a class of drugs called biguanides.
It is usually taken once or twice per day, most often with dinner. It is an extremely safe drug that is usually well-tolerated.
When someone takes Metformin, it lowers blood sugar levels by stopping the production of glucose from the liver, and also prohibits the body from absorbing all of the sugar in the food you eat, thus increasing insulin sensitivity.
While Metformin is no magical drug, taking the medicine with an increase in exercise and an improvement in diet can lead to moderate weight loss, lower blood sugar levels, and improved HbA1c levels.
Metformin is cheap and widely accessible in the United States. Most insurance plans, including Medicare, cover the drug.
What are the side effects of Metformin?
The common side effects of Metformin are (usually) mild, and include the following:
- Stomach pain
- Loss of appetite
- Weight loss
- Some patients do gain weight, but this is rare
- If taken in with insulin therapy, low blood sugar may occur
You can learn more about the potential side effects of Metformin in our guide: Metformin Side Effects: What You Need to Know
Is taking Metformin for prediabetes safe?
Metformin is seen as a safe and relatively well-tolerated medicine that is inexpensive as a longer-term option for people with prediabetes with other risk factors for diabetes, such as obesity, family history, or sedentary lifestyle.
In 2007, the American Diabetes Association started recommending Metformin as a treatment option for people with prediabetes to help prevent the onset of type 2 diabetes (T2D).
Per the American Diabetes Association, Metformin “should be considered” for prediabetes patients with a BMI > 35 and patients under 60.
However, it is not approved by the Food and Drug Administration for people with prediabetes.
Instead, many physicians prescribe the drug “off-label” to their prediabetic patients in the hope that it will help delay or even prevent the onset of T2D.
“Off-label” means that a medicine is prescribed for a purpose other than its intended use, which in this case is to treat type 2 diabetes.
However, even with this loophole in the system, less than 4% of adults with prediabetes currently use Metformin.
What are some of the pros of taking Metformin for prediabetes?
Taking Metformin is a pretty low-risk intervention. If you have a physician who is willing to write you a prescription off-label, then taking the medicine may be worth a shot.
It is generally well-tolerated, and people only usually have minor side effects (and usually just within the first few weeks of taking it, until their bodies adapt).
It can certainly help lower blood sugar and HbA1c levels, both of which, when high, are risk factors for developing type 2 diabetes.
According to the Mayo Clinic, “You may notice an improvement in your blood glucose control in 1 to 2 weeks, but the full effect of blood glucose control may take up to 2 to 3 months.”
A positive side effect of taking Metformin, researchers are finding, is that it also may help in the fight against cancer, heart disease, obesity, neurodegenerative conditions, vision issues, and may even act as an anti-aging supplement.
In addition to improved diet and increased exercise, Metformin can lead to weight loss, which can also help prevent type 2 diabetes, although taking Metformin alone as a weight loss pill is not an effective strategy.
Most importantly, taking Metformin is effective in preventing or delaying type 2 diabetes in adults who are at high risk for the disease (prediabetes being a risk factor). Taking the medicine daily has a comparable effect to lifestyle interventions like diet and exercise.
What are the cons of taking Metformin for prediabetes?
Taking Metformin if you have prediabetes isn’t for everyone.
Taking Metformin can cause uncomfortable side effects, such as gastrointestinal issues like nausea and vomiting and chronic diarrhea, which can be hard to manage, especially with rigid work schedules and social commitments.
Additionally, if you are overweight or obese, Metformin isn’t a guarantee for weight loss. In one study, 29% of people lost 5% or more of their body weight, and just 8% lost around 10%.
Some people should also avoid Metformin if they have kidney issues or kidney disease.
Metformin can cause lactic acidosis, which is a serious and potentially deadly condition in which too much lactic acid builds up in the blood.
The FDA has even released a “black box” warning about this dangerous side effect. Always talk with your doctor first to see if taking Metformin is appropriate for you and your health goals.
Metformin is an extremely popular prescription medicine for people with type 2 diabetes.
However, it is becoming more commonly used as an “off label” medicine for people who are overweight, obese, have type 1 diabetes with severe insulin resistance, and for people with prediabetes.
It can potentially delay the onset or even prevent the development of type 2 diabetes entirely in this population. When taken in conjunction with an improved diet and increased exercise, it can also aid in weight loss.
It is cheap and easily accessible in the United States, and is covered by nearly all health insurance plans, including Medicare.
However, it may cause disturbing gastrointestinal issues, including nausea, vomiting, and chronic diarrhea. Metformin alone won’t result in significant weight loss, and for people who have kidney issues, it can cause a potentially deadly complication called lactic acidosis.
Kidney issues are more common in people with diabetes, so make sure to talk with your doctor before dabbling with Metformin to see if taking the medication is appropriate for you and your health goals.
For more information about prediabetes, we suggest reading: