Can You Take Metformin for Prediabetes?

Prediabetes is a condition impacting millions of people, but many people might not even know they have it. 

Prediabetes typically doesn’t have any symptoms, but it can lead to type 2 diabetes if you don’t manage it.

Metformin is the typical first drug of choice to treat type 2 diabetes, but what about prediabetes?

What is prediabetes?

Prediabetes, otherwise known as borderline diabetes or impaired glucose tolerance, is a condition where your blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes. It is a major risk factor for developing type 2 diabetes later in life.

Prediabetes occurs from insulin resistance. Insulin is a hormone your pancreas produces to help lower blood glucose levels.

Insulin resistance occurs when your pancreas doesn’t produce enough insulin to control your blood sugar levels, or your body stops responding to insulin effectively. When this happens, blood sugar levels rise, and prediabetes and type 2 diabetes can develop. 

Prediabetes can be reversible with lifestyle modifications. However, if it’s left untreated, it often progresses to type 2 diabetes, sometimes in just a few years.

There are several risk factors for developing prediabetes, including:

  • Being overweight or obese (body mass index of 25 or greater)
  • Carrying excess weight around your midsection
  • Being 45 years or older
  • Having an immediate family member with type 2 diabetes
  • Being physically active less than 3 times per week
  • Having had gestational diabetes (diabetes during pregnancy) or birthed a baby who weighed more than 9 pounds
  • Having polycystic ovary syndrome (PCOS)
  • Having high blood pressure 
  • Being a smoker

What is metformin?

Metformin is one of the most commonly prescribed medications for type 2 diabetes. Metformin is the generic name most commonly prescribed, and the brand name for metformin is Glucophage. 

This medication doesn’t cause low blood sugar (hypoglycemia), which is one of metformin’s major benefits.

Metformin is in a drug class called biguanides. Biguanides help reduce the amount of sugar your liver makes while improving insulin sensitivity, which helps reduce high blood sugar. There are two types of metformin – regular and extended-release (XR).

The common dosage for metformin ranges from 500 milligrams to a maximum of 2,550 milligrams per day. 

It’s recommended to split the dose of regular metformin (not extended-release) among meals, typically two to three times per day. 

metformin side effects

Can metformin treat prediabetes?

Metformin can help improve insulin sensitivity and reduce high blood sugar levels. While it’s not a cure for prediabetes (taking it doesn’t mean you won’t get type 2 diabetes later on), it can help improve your blood sugar control. 

Metformin might be especially beneficial for prediabetes if you couple it with sustainable lifestyle changes like healthy eating and physical activity.

The FDA hasn’t approved metformin for the treatment of prediabetes. 

However, your healthcare provider might recommend trying metformin if you have prediabetes, especially if you have:

  • A longer history of having prediabetes
  • Other risk factors for developing type 2 diabetes
  • If your blood sugar levels haven’t improved despite making lifestyle changes.

The American Diabetes Association says that metformin “should be considered” in some patients with prediabetes, especially those considered obese. 

In addition, metformin use in people with prediabetes might help reduce the risk of cardiovascular disease (CVD), including heart attack and stroke (1).

According to a meta-analysis of three studies, researchers concluded that using metformin decreased how often prediabetes turned into diabetes (2). 

Metformin helped reduce the conversion to type 2 diabetes in both high doses (850 milligrams twice daily) and lower doses (250 milligrams 2-3 times daily).

glyco optimizer

How does metformin work for prediabetes?

Many things can impact your blood sugar. Your diet plays a big role in your blood sugar levels. 

Eating foods rich in carbohydrates (foods like grains, fruit, starchy vegetables, as well as refined sugar in sweetened foods and drinks) raises your blood sugar. However, your body can also make your blood sugar levels rise, despite your diet. This can happen during times of stress and illness.

Metformin helps with prediabetes in the same way it helps treat type 2 diabetes: your liver releases stored sugar (glycogen) during fasting or between meals, raising your blood glucose levels. 

Metformin helps your liver release less stored sugar, a process called gluconeogenesis. 

It also helps address the root of prediabetes, which is insulin resistance. 

Metformin improves your sensitivity to insulin, which helps lower your blood sugar levels (3). The more sensitive your body is to insulin, the less you’re likely to develop high blood sugar and diabetes.

Do doctors prescribe metformin for prediabetes?

Some healthcare providers might prescribe metformin for prediabetes even though it isn’t FDA-approved for that reason.

Can metformin prevent type 2 diabetes?

Metformin can help lower blood sugar levels and might help you come out of the prediabetes range. However, metformin is not a permanent fix for prediabetes and won’t necessarily reverse it. 

Metformin might help prevent type 2 diabetes in some people, but it’s not guaranteed to prevent it long-term. Some people might take metformin and see an improvement in their blood sugars, only to still develop type 2 diabetes later in life.

how to reverse type 2 diabetes

When do you start metformin for prediabetes?

Your healthcare provider might recommend starting metformin for prediabetes if your hemoglobin A1c is still increasing despite making lifestyle changes. 

The A1c range for prediabetes is 5.7-6.4, so being on the high end of that range might warrant trying metformin. Prediabetes can also be diagnosed using a glucose tolerance test or fasting blood sugar.

How much metformin should a prediabetic take?

Your healthcare provider will recommend a dose of metformin for your prediabetes. Common doses range from 500 milligrams to a maximum of 2,550 milligrams daily. 

Your healthcare provider might recommend gradually increasing your dose as tolerated. Or they  might recommend increasing it if your A1c isn’t showing improvement after 3-6 months.

What are the side effects of metformin?

You might experience some side effects when you start taking metformin. Side effects are usually the most noticeable when you first start taking a new medication and tend to decrease over time as you gain tolerance to it.

The common side effects of taking metformin include:

  • Heartburn
  • Stomach pain
  • Nausea or vomiting
  • Bloating
  • Gas
  • Diarrhea
  • Constipation
  • Weight loss
  • Headache
  • Metallic taste in your mouth

Metformin might also reduce your body’s ability to absorb vitamin B12 in your stomach. It’s estimated that 6-30% of people taking metformin experience vitamin B12 deficiency (4). According to studies, the higher the metformin dose, the greater the risk of vitamin B12 deficiency. 

Your healthcare provider might recommend B12 injections if you become deficient in vitamin B12 while taking metformin for prediabetes.

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What happens if you stop taking metformin for prediabetes?

If you stop taking metformin for prediabetes, your blood sugar levels might rise again. It’s possible to get diabetes after stopping metformin for prediabetes, especially if you didn’t also make lifestyle changes like eating healthier and being more active.

Remember that it’s possible to get type 2 diabetes even if you make healthy lifestyle changes and/or take metformin for prediabetes.

If your pancreas has been producing more insulin to counteract your high blood sugar, it can then lead to dysfunction in its ability to make β-cells, the ones responsible for making insulin. This is called insulin deficiency, and it can’t be reversed.

Natural metformin alternatives for prediabetes

If you want to try a natural metformin alternative for prediabetes, there are several supplements that you can try. 

Bear in mind that everyone responds differently to natural treatments, so you should have blood work done 3-6 months after starting a natural alternative to determine if it’s helping you.

Here are some natural supplements that have been proven to improve insulin sensitivity and might help with prediabetes:

1) Inositol

Inositol is a vitamin-like substance that mimics the action of insulin. Myo- and D-chiro inositol have been studied for their ability to improve insulin sensitivity and are often recommended for women with insulin resistance.

Inositol might improve blood sugar levels in people with prediabetes, and it’s even been studied for the potential to reduce the incidence of type 2 diabetes in children (5).

The benefits of inositol have been studied in direct comparison with metformin in insulin-resistant women. Both metformin and myo-inositol were found to have similar positive effects on insulin levels and fasting blood sugar (6).

Inositol can be used in different blends (blends of myo- and D-chiro-inositol are popular), dosages, and forms, including powders and capsules for use as a natural metformin alternative for prediabetes.

2) Berberine

Berberine is a compound found in plants that are often used as a natural metformin alternative

Berberine has been found to improve insulin sensitivity while also helping reduce blood triglyceride levels and waist circumference, some of the signs of insulin resistance (7). 

It might also assist with weight loss, which can help prevent prediabetes from turning into diabetes in some cases (8).

A pilot study compared berberine vs metformin directly for their potential to help treat type 2 diabetes (9). 

The researchers found that berberine produced identical results as metformin in improving blood glucose metabolism. A1c, fasting blood sugar, post-prandial blood sugar, and insulin levels.

berberine benefits

3) Aloe vera

According to a 2015 review of studies, aloe vera gel complex may help lower blood sugar, promote healthy cholesterol levels, reduce body fat and weight, and reduce insulin resistance in obese subjects with prediabetes (10).

According to another meta-analysis of studies, aloe vera significantly reduced fasting blood sugar levels in people with prediabetes (11).

Lifestyle changes to help prediabetes


Getting more exercise is one of the best ways to improve insulin resistance and help reverse prediabetes. Muscle tissue takes up glucose during exercise, even if you have insulin resistance. 

Blood sugar levels tend to be lower after being active and can even remain lower for up to 24 hours after physical activity.

Aim to get at least 30 minutes of moderate to vigorous physical activity on most days of the week, with a goal of at least 150 minutes per week. 

does exercise boost energy

Cut back on sugars

Added sugars are prevalent in most processed foods, even those that might seem healthy. Cereals, yogurts, granola bars, and even savory foods like soups and meat can have added sugar, which spikes blood sugar and insulin levels.

Check the nutrition label and aim to get no more than 50 grams of added sugar per day – the lower, the better.


Metformin can help improve insulin sensitivity and lower blood sugar levels, making it a possible choice for both prediabetes and type 2 diabetes.

However, metformin won’t necessarily reverse prediabetes or prevent type 2 diabetes forever. Metformin is best used with sustainable, healthy lifestyle changes to promote healthy blood sugar levels.

Explore More

metformin benefits for non diabetics

Can You Take Metformin If You Aren’t Diabetic?


  1. Murillo, Jaime E, Chace McNeil, Kathryn Van Nest, Jamie Schaeffer, Lynn Polingo, Solomon Adjei, Victoria Shapiro, Ben Wiegand and Vojta Deneen. Off-Label Metformin in Patients with Prediabetes is Associated with Improved Cardiovascular Outcomes. (2021)
  2. Lily M, Godwin M. Treating prediabetes with metformin: systematic review and meta-analysis. Can Fam Physician. 2009 Apr;55(4):363-9. Erratum in: Can Fam Physician. 2010.
  3. Wiernsperger NF, Bailey CJ. The antihyperglycaemic effect of metformin: therapeutic and cellular mechanisms. Drugs. 1999.
  4. Kim J, Ahn CW, Fang S, Lee HS, Park JS. Association between metformin dose and vitamin B12 deficiency in patients with type 2 diabetes. Medicine (Baltimore). 2019. ​​
  5. Mancini M, Andreassi A, Salvioni M, Pelliccione F, Mantellassi G, Banderali G. Myoinositol and D-Chiro Inositol in Improving Insulin Resistance in Obese Male Children: Preliminary Data. Int J Endocrinol. 2016.
  6. Nas K, Tűű L. A comparative study between myo-inositol and metformin in the treatment of insulin-resistant women. Eur Rev Med Pharmacol Sci. 2017.
  7. Pérez-Rubio KG, González-Ortiz M, Martínez-Abundis E, Robles-Cervantes JA, Espinel-Bermúdez MC. Effect of berberine administration on metabolic syndrome, insulin sensitivity, and insulin secretion. Metab Syndr Relat Disord. 2013.
  8. Asbaghi O, Ghanbari N, Shekari M, Reiner Ž, Amirani E, Hallajzadeh J, Mirsafaei L, Asemi Z. The effect of berberine supplementation on obesity parameters, inflammation and liver function enzymes: A systematic review and meta-analysis of randomized controlled trials. Clin Nutr ESPEN. 2020.
  9. Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism. 2008.
  10. Radha MH, Laxmipriya NP. Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review. J Tradit Complement Med. 2015.
  11. Suksomboon N, Poolsup N, Punthanitisarn S. Effect of Aloe vera on glycaemic control in prediabetes and type 2 diabetes: a systematic review and meta-analysis. J Clin Pharm Ther. 2016.

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