What Happens When You Stop Taking Metformin for Diabetes?

Metformin is one of the most commonly prescribed medications to treat type 2 diabetes. 

Over 120 million people worldwide have been prescribed metformin. 

Some people stay on metformin most of their lives, while others stop taking metformin at some point. 

If you’re considering stopping metformin, you might be wondering what could happen after you stop taking it. Keep reading to find out.

What is metformin?

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

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).

Metformin doesn’t cause low blood sugar (hypoglycemia), which is one of its benefits. Because it doesn’t cause low blood sugar, people with type 2 diabetes can take metformin along with other medications like sulfonylureas and injectable insulin.

The usual dosage for metformin ranges from 500 milligrams to a maximum of 2,550 milligrams per day. Healthcare providers usually recommend you split the dose among meals, typically three times per day. 

Metformin is most commonly used for type 2 diabetes. It’s also used to help treat polycystic ovarian syndrome (PCOS), a hormonal disorder in women that can stem from insulin resistance

One of the benefits of metformin is that it may support weight loss and doesn’t promote weight gain like some diabetes medications. If you’re overweight, weight loss of 5-10% of your body weight can improve your blood glucose levels and improve insulin sensitivity.

RELATED: Metformin Recall: Is Your Medication Affected?

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Side effects of metformin

The most common metformin side effects are gastrointestinal-related. If you take metformin, you might experience some of these side effects:

Metformin might also reduce your stomach’s ability to absorb vitamin B12. Approximately 6-30% of people taking metformin experience vitamin B12 deficiency. According to studies, the higher the metformin dose, the greater the risk of vitamin B12 deficiency. 

Vitamin B12 is important for creating DNA and red blood cells. Vitamin B12 deficiency can lead to anemia, which is when you have lower levels of red blood cells than is healthy. 

Anemia from vitamin B12 deficiency is pernicious anemia and comes with symptoms such as:

  • Weakness, tiredness, or lightheadedness
  • Heart palpitations and shortness of breath
  • Pale skin
  • A smooth tongue
  • Constipation, diarrhea, loss of appetite, or gas 
  • Nerve problems like numbness or tingling, muscle weakness, and problems walking
  • Vision loss
  • Mental problems like depression, memory loss, or behavioral changes

Most people who take metformin experience minor side effects. However, there is a risk of more severe side effects from taking metformin. 

Lactic acidosis is a rare but serious condition where your body creates more lactic acid than your body can clear. 

The symptoms of lactic acidosis usually set in quickly and include:

  • Abdominal or stomach discomfort
  • Decreased appetite
  • Diarrhea
  • Fast, shallow breathing
  • Discomfort
  • Muscle pain or cramping
  • Unusual sleepiness, tiredness, or weakness

Reasons people might stop taking metformin

Side effects

People who experience adverse side effects from metformin might wish to discontinue its use and try another diabetes medication. 

Severe negative side effects that disrupt your life can negate the potential benefit of taking the medication and warrant stopping metformin.

Controlled blood sugar

If your hemoglobin A1c (a measure of long-term blood glucose control) is below the American Diabetes Association’s recommendation of below 7%, that means your blood glucose is well-controlled. 

If you consistently meet your blood sugar goals, your healthcare provider might suggest stopping metformin.

Fasting blood sugar below 100 mg/dL is in the range of a person without diabetes. If your fasting blood sugar is consistently in that range, it’s a possible indicator that you might be able to control your diabetes through lifestyle alone.

If you take metformin to control gestational diabetes (diabetes during pregnancy), you’ll likely be able to stop taking metformin after delivering your baby.

Not meeting blood sugar goals

Some people eventually need more than metformin to control their diabetes. This is especially true if you’ve had diabetes for a long time.

If your healthcare provider recommends a change in medications, they might advise you to stop taking metformin.

RELATED: Signs Metformin Is Not Working and What to Do.

Impaired kidney function

Your kidneys clear medication from your system so it doesn’t build up to unhealthy levels. If you have chronic kidney disease or other renal impairment, healthcare providers don’t recommend taking metformin. 

If your glomerular filtration rate (how effectively your kidneys filter blood) is below 45, metformin use is not recommended. 

What are the side effects of stopping metformin?

The biggest potential side effect of stopping metformin is higher blood sugar levels. If you stop taking metformin, you may become less sensitive to insulin, which raises blood glucose levels.

Stopping metformin can also make your liver release more sugar than it did while taking metformin, also raising blood glucose.

If you take metformin for PCOS, you might experience more symptoms from PCOS like irregular menstrual cycles and increased testosterone levels after stopping metformin.

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Risks of stopping metformin

Stopping metformin may increase your risk of diabetes complications if your blood sugar isn’t well-controlled. 

Some of the potential risks of long-term high blood sugar include:

  • Heart (cardiovascular) disease: people with diabetes are twice as likely to have heart disease compared to someone without diabetes.
  • Stroke: Diabetes increases your risk of stroke.
  • Kidney disease and failure: High blood sugar from diabetes can damage your kidneys and can lead to kidney disease. About one in four people with diabetes have kidney disease.
  • Poor wound healing leading to amputations: High blood sugar inhibits proper wound healing. Diabetes is believed to be the leading cause of leg amputations worldwide.
  • Neuropathy is when high blood glucose damages your nerves. This can cause symptoms like numb and tingling legs and feet and delayed stomach emptying (gastroparesis).
  • Damage to the nerves in your eyes is retinopathy, which can lead to blindness if not treated.

Stopping metformin safely

It’s important that you understand the potential risks of stopping any medication, including metformin. 

There aren’t any official guidelines on how to stop metformin. You should consult with your healthcare provider and avoid stopping metformin on your own. 

Have a conversation with your healthcare provider about your alternatives for controlling your diabetes without metformin. 

How long does metformin stay in your system after stopping?

Metformin will remain in your system for around 100 hours after your last dose. The rate at which your body clears metformin from your system depends on many factors like how long you took metformin, your dosage, other health conditions, and your body mass.

Metformin withdrawal 

Metformin withdrawal isn’t a common phenomenon, which is good news if you’re planning on stopping metformin. 

The only mention of “metformin withdrawal” was in a study related to the use of metformin for managing polycystic ovary syndrome. 

Metformin alternatives for diabetes: natural and pharmaceutical

Pharmaceutical Alternatives

There are several pharmaceutical alternatives to metformin for managing diabetes.


If the reason for stopping metformin was due to poor kidney function or poor blood sugar control, your doctor might suggest insulin as a good alternative. Insulin effectively improves glycemic control since it mimics your body’s ability to control blood sugar levels. 

One of the potential risks of blood sugar-lowering medications like insulin is the risk of low blood sugar. Your risk of low blood sugar is greater if you have kidney disease since your kidneys don’t clear the insulin from your body as quickly as someone with healthy kidneys. If insulin levels build up, you might experience low blood sugar.


Sulfonylureas are another common medication to treat type 2 diabetes. Popular sulfonylureas include glipizide and glyburide, which help stimulate your pancreas to make more insulin. Unlike metformin, these medications carry a risk of low blood sugar.

Repaglinide (Prandin)

Repaglinide is a diabetes medication that people with severe kidney disease (stage 4-5) can use. Patients with declining renal function can use it because it’s primarily absorbed in the stomach and metabolized in your liver, not your kidneys.

Repaglinide works to lower blood glucose by stimulating the beta cells of your pancreas to produce more insulin. Like sulfonylureas, repaglinide comes with a risk of low blood sugar.

SGLT2 inhibitors

Canagliflozin (Invokana), Dapagliflozin (Farxiga), and Empagliflozin (Jardiance) help lower blood sugar by increasing the amount of sugar excreted in your urine. 

Some of the potential benefits of this type of medication are possible improvements in cardiovascular outcomes and weight loss. SGLT2 inhibitors don’t typically cause low blood sugar.

glyco optimizer

Natural alternatives

If you prefer not to take diabetes medications, there are several natural metformin alternatives you could consider. 

Myo-inositol and D-chiro inositol

These vitamin-like substances have insulin-mimetic properties, which means they mimic insulin’s action. Myo- and D-chiro inositol have been studied for their ability to improve insulin sensitivity.

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

Inositol has been studied in direct comparison with metformin in insulin-resistant women. Both metformin and myo-inositol had similar positive effects on insulin levels, fasting blood sugar, and hormone levels associated with PCOS. 


Berberine is a compound in plants that we can use as a natural treatment for diabetes. Studies found that berberine improved insulin sensitivity while also helping to reduce blood triglyceride levels and waist circumference. Berberine may also promote weight loss.

A pilot study compared berberine to metformin directly for its potential to help treat type 2 diabetes. 

The researchers reported that berberine produced identical results as metformin in terms of improving blood glucose metabolism. A1c, fasting blood sugar, postprandial blood sugar, and insulin levels all improved after taking berberine.

Bitter melon

Bitter melon is a vegetable people use in Asia, South America, India, the Caribbean, and East Africa. It has shown anti-diabetic properties in studies, as it can increase insulin secretion while decreasing insulin resistance.


Taking cinnamon can significantly reduce blood sugar levels while promoting healthy cholesterol levels. Cinnamon is a safe and generally well-tolerated natural metformin alternative. 

Despite its potential efficacy, you shouldn’t stop taking metformin to pursue a natural alternative without consulting your healthcare provider.


Metformin is a medication primarily used to treat type 2 diabetes. Despite its efficacy, there are reasons for stopping metformin. 

Fortunately, there aren’t adverse side effects from stopping metformin. However, long-term consequences of high blood sugar can arise if you don’t meet your blood sugar goals after stopping metformin.

Explore More

natural metformin

Find out 5 Natural Alternatives to Metformin for Diabetes & Insulin Resistance.


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  7. 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. https://pubmed.ncbi.nlm.nih.gov/28724173/
  8. Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism. 2008;57(5):712-717. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2410097/
  9. Liu Z, Gong J, Huang W, Lu F, Dong H. The Effect of Momordica charantia in the Treatment of Diabetes Mellitus: A Review. Evid Based Complement Alternat Med. 2021. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826218/

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