Although the medication metformin is often prescribed to people with type 2 diabetes, those living with type 1 diabetes might also benefit from the drug.

Let’s dive into what metformin is, why it might be used, and what you should be aware of if you’re considering it as a part of your diabetes management plan.

What Is Metformin?

Metformin belongs to a class of drugs called biguanides. It works by lowering blood glucose (sugar) production in the liver and increasing insulin sensitivity, which helps the body use insulin more effectively. It’s typically taken in pill form, and it’s one of the most commonly prescribed medications for managing blood sugar levels.

What Is Metformin Usually Used For?

Metformin is usually prescribed to people with type 2 diabetes to help control their blood sugar levels. It can also be used in combination with other diabetes medications or insulin. Besides its primary use for diabetes, metformin is sometimes prescribed for conditions like polycystic ovarian syndrome (PCOS) and for managing weight in certain situations.

When Might a Person With Type 1 Diabetes Use Metformin?

While metformin is not a primary treatment for type 1 diabetes, there are specific circumstances where it might be considered. Research has shown that metformin can be particularly beneficial for people with type 1 diabetes who are insulin-resistant.

Insulin resistance occurs when the body does not respond properly to insulin, making it harder to control blood sugar levels. According to a review in the journal Metabolism, people with type 1 diabetes who are overweight or have difficulty controlling their blood sugar levels — despite using insulin — might benefit from metformin. It can help reduce the amount of insulin needed and improve blood sugar control by enhancing insulin sensitivity.

Can You Use Insulin With Metformin?

Metformin is not a replacement for insulin therapy but can be taken alongside insulin. For people with type 1 diabetes, taking metformin and insulin together can help them better control their weight and reduce the need for higher insulin doses. The use of metformin alongside insulin can, in some cases, be particularly beneficial for individuals who have difficulty managing their diabetes with insulin alone.

It’s important to note that, if you start taking metformin for type 1 diabetes, you should be monitored by a health care provider. Adjustments to insulin dosage might be necessary to avoid hypoglycemia (low blood sugar), which can occur if insulin and metformin lower blood sugar levels too much.

What Are Potential Risk Factors and Benefits of Metformin?

Below are some potential benefits of using metformin as part of your diabetes care plan:

• Improved blood sugar control — Metformin can help lower blood sugar levels, making it easier to manage diabetes.
• Weight management — Some studies have shown that metformin can help with weight loss or prevent weight gain, which can be beneficial for people with type 1 diabetes who are overweight.
• Heart health — Metformin has been shown to have cardiovascular benefits, potentially reducing the risk of heart disease, which is a common complication of diabetes.

Notably, a major study called the Removal trial did not find a significant reduction in hemoglobin A1c (HbA1c) levels in people with type 1 diabetes taking metformin. (HbA1c levels reflect a person’s average blood glucose levels over the previous two to three months.) The study did show, however, that metformin may play a role in managing cardiovascular risk. This study highlighted that while metformin may aid in weight management and reducing insulin doses, its impact on long-term health outcomes in type 1 diabetes remains uncertain.

Below are some potential risks of using metformin:

• Hypoglycemia — People who metformin along with insulin risk having their blood sugar levels drop too low. Talk to your doctor about this risk and how to best treat low blood sugar.
• Lactic acidosis — Although rare, metformin can cause a serious condition called lactic acidosis, where lactic acid builds up in the blood, leading to symptoms like muscle pain, breathing difficulties, and stomach pain.
• Gastrointestinal issues — Common side effects include nausea, diarrhea, and stomach discomfort.
• Low vitamin B12 levels — Having low levels of vitamin B12 can sometimes cause pain, tingling, and dizziness. Talk with your health care provider about ways to ensure you’re getting enough B12 in your diet.

What Are Possible Side Effects of Metformin?

Like all medications, metformin treatment may lead to side effects. Many of the side effects go away as your body gets used to the drug. Your doctor can discuss some ways to avoid or lessen some of these side effects. Consult with your doctor if any side effects persist or become troublesome or if you have any questions about them.

Some possible side effects include:

• Belching or excess gas
• Heartburn or indigestion
• Metallic taste in mouth
• Nausea and/or vomiting
• Weight loss
• Loss of appetite
• Stomach upset or pain

People experiencing gastrointestinal side effects may consider trying the extended-release (ER) formulation of metformin. The ER formulation releases the medication more slowly into the bloodstream, which can help reduce the severity of side effects such as nausea and diarrhea. However, when used together with insulin therapy, this formulation may carry a higher risk for hypoglycemia.

Talk to Your Doctor About Type 1 Diabetes Treatment

While metformin is not traditionally used for type 1 diabetes, it may offer benefits for certain individuals. It’s also worth mentioning that lifestyle changes, such as diet and exercise, play a crucial role in managing diabetes, even type 1. Metformin can be an effective addition to a comprehensive type 1 diabetes treatment plan that includes these lifestyle modifications. Always consult with your doctor to determine if metformin is a suitable option for you and discuss any potential risks.

Connect With Others Who Understand

On myT1Dteam, the social network for people with type 1 diabetes and their loved ones, more than 3,000 members come together to ask questions, give advice, and share their stories with others who understand life with type 1 diabetes.

Are you living with type 1 diabetes? Share your experience in the comments below, or start a conversation by posting on your Activities page.