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Does metformin help with insulin resistance?

Metformin increases insulin sensitivity, aiding in the management of insulin resistance
Rebecca Rovenstine writer headshot
By | Jul. 30, 2024 Medically reviewed by Marissa Walsh, Pharm.D., BCPS-AQ ID
Rx tablets: Metformin-for-insulin-resistance

Key takeaways

  • Metformin treats insulin sensitivity, which can help improve insulin resistance.

  • Metformin is most commonly prescribed to patients with Type 2 diabetes but has many off-label uses.

  • The most common side effects of metformin are conditions related to gastrointestinal distress.

In this article:

Metformin, a popular medication for those with diabetes, helps to regulate blood sugar levels. Insulin resistance, a condition that happens when the body does not respond properly to the hormone insulin, is a common issue for those with prediabetes and Type 2 diabetes. Those who have insulin resistance may benefit from using the prescription drug metformin. Keep reading to learn what the experts had to say.

Does metformin help with insulin resistance?

“Metformin is an oral medication used to regulate blood sugar, particularly in patients with Type 2 diabetes,” explained Dr. Lauren Donnangelo, a specialist in gastroenterology and obesity medicine at True You Weight Loss. 

How does metformin work exactly? Dr. Libu Varughese, an MD, endocrinologist, and medical adviser at Aeroflow Diabetes, told us, “Its exact mechanism of action is unknown. Our understanding is that it works by reducing the sugars that the liver generates overnight, lowering the morning sugar levels.”

Before explaining if the prescription medication metformin can help with insulin resistance, it’s important to understand two terms: insulin sensitivity and insulin resistance.

  • Insulin sensitivity measures how well your body’s cells respond to insulin and how the blood glucose levels change in response.
  • Insulin resistance means that a person has impaired insulin sensitivity and the body does not use insulin as effectively.

“Metformin increases insulin sensitivity, which helps with insulin resistance,” said Dr. Donnangelo.

While patients with Type 2 diabetes are most commonly given metformin, those without diabetes can still take the medication if they have insulin resistance or other related conditions. This includes managing conditions for individuals with pre-diabetes, gestational diabetes, polycystic ovarian syndrome, and obesity.

Historically, metformin is not a go-to treatment for all types of diabetes mellitus, as those with Type 1 diabetes produce very little insulin and must administer it throughout the day. It is not licensed for patients with Type 1 diabetes, but sometimes metformin may be given for off-label use. Current research indicates it may be beneficial for some patients with Type 1 diabetes, but not all. 

Benefits of metformin treatment

Those taking metformin may see a variety of benefits. This includes the following:

  • Lower fasting blood sugar levels
  • Better regulation of blood sugar
  • Treatment of Type 2 diabetes
  • Potential improvements in insulin-resistant diseases, including: 
    • Pre-diabetes
    • Polycystic ovary syndrome
  • Beneficial effects on hemoglobin A1c
  • Cardiovascular benefits such as lower cardiovascular mortality (deaths from heart-related conditions)
  • Improved body weight for obese and overweight individuals (according to the body mass index scale), especially for those on antipsychotic medications
  • Reduced risk of developing dementia or Alzheimer’s disease
  • Previous studies have shown metformin can be an anti-cancer drug and may reduce the risk of some types of cancer
  • Another promising use of metformin is as an anti-aging drug. According to a 2021 critical review, metformin does this “via its ability to reduce early mortality associated with various diseases, including diabetes, cardiovascular disease, cognitive decline, and cancer.”

Metformin medication dosage and management 

Metformin is a generic oral medication typically taken daily as an immediate-release tablet, extended-release tablet, or liquid solution. Name brands may include Fortamet, Glucophage, Glumetza, and Riomet. Several drugs combine metformin with other drugs, such as Janumet, Trijardy, and Xigduo XR.

“The usual starting dose for immediate-release metformin is 850 mg daily, or 500 mg once to twice daily (depending on the formulation), and then increased as tolerated,” said Dr. Donnangelo. “The usual starting dose for extended-release metformin is 500 mg once to twice daily, then increased as tolerated. The maximal daily dose of metformin is 2,000-2,550 mg, depending on the formulation.”

The dosage will change depending on how your body tolerates the drug, so regular follow-up appointments with your doctor are important. Metformin works best over time. Some individuals may notice improvement within 48 hours, while a significant difference can begin four days to a week or two weeks later.

Typically, it is best to take the prescription drug metformin with a meal. No specific foods or drinks will interact with Metformin, but some, such as carb-heavy foods and saturated fats, will make it harder to regulate blood sugar. One of the best treatments for diabetes is weight reduction and a healthy diet, so cutting excessive fatty and sugary foods from your diet is always a good idea.

Some prescription drugs and alcohol can cause lactic acidosis when on metformin, which is life-threatening. Due to this, it is always important to discuss with your medical provider medication interactions before starting any new drugs.

Potential side effects of metformin for insulin resistance

Like any prescription drug, there are side effects that can happen as a result of taking metformin. Common side effects include the following:

More serious side effects may include: 

Lactic acidosis may be more prevalent in patients with kidney and liver disease. However, earlier research found metformin may be beneficial to patients with non-alcoholic fatty liver disease. A 2024 study also stated, “In patients with chronic kidney disease, metformin may provide long-term benefits,” though the researchers stress the importance of frequent Vitamin B12 level testing.

If you have any serious side effects or adverse events while on metformin, it is vital to contact your doctor immediately.