If you’ve been taking metformin for some time and haven’t seen results, or if you’re experiencing harmful side effects, you may wonder when and how to stop taking it. 

However, stopping a prescription medication once you’ve been on it for a while can be more complicated than you might think. 

This article will explain everything you need to know about when and how to stop taking metformin if it’s no longer working or if you are experiencing side effects. 

Close-up of metformin pill

Key Points:

  • Metformin is often discontinued due to lack of effectiveness, severe side effects, lifestyle incompatibility, or insurance changes.
  • Stopping metformin suddenly can lead to adverse health effects like higher blood sugars and potential diabetes complications.
  • Consult a doctor before stopping metformin. Gradual weaning off is usually recommended to avoid negative health impacts.
  • Alternatives to metformin include other diabetes medications, combination drugs, or lifestyle changes.

Why would you want to stop taking metformin? 

Metformin is extremely popular, generally safe, affordable, and widely accessible in the United States. People who take metformin for improved blood sugar levels (and modest weight management) generally find it effective, with short-term and minimal side effects.

See more in: Metformin Side Effects (Common and Serious).

Metformin is most commonly used by people with type 2 diabetes and prediabetes (a condition in which blood glucose levels are high, but not in the range for a diabetes diagnosis), and it is sometimes prescribed “off-label” for those experiencing insulin resistance (a condition in which the body does not use insulin efficiently) or for weight management. 

However, there are some reasons why people who are on metformin may wish to stop taking it. 

Metformin isn’t working 

Not everyone who takes metformin gets to enjoy improved blood sugar and HbA1c (A1c) levels (a measure of glucose levels over the previous 2 to 3 months), let alone the weight loss that is often promised with the drug. 

If you’ve been taking metformin for several months, but are not seeing improvements in your health and quality of life, you may be reassessing why you’re spending money on the drug to begin with.

This is a common reason why people stop taking metformin and is completely reasonable. 

Metformin does not and will not work for everyone who takes it. 

You’re experiencing harmful side effects 

Side effects of metformin include the following:

  • Nausea
  • Diarrhea
  • Bloating
  • Gas
  • Decreased appetite
  • Vomiting 
  • Stomachache 
  • Weight loss 
  • Metallic taste in your mouth
  • Heartburn
  • Constipation 
  • Low blood sugar (if you take insulin

These side effects are normally minimal and go away within a few weeks of starting metformin. 

Learn more in: Metformin Side Effects: What You Need to Know.

However, for some people, the side effects are so severe and last so long (or become permanent) that it completely disrupts their lives, rendering them unable to work or maintain a social life or close relationships.

If you’re experiencing side effects such as chronic diarrhea, debilitating low blood sugars, or severe bloating, gas, vomiting, or nausea for more than a few weeks after starting the medication, it may be time to talk to your doctor about weaning yourself off metformin and finding an alternative drug. 

Read more in: The Best Alternatives to Metformin for Type 2 Diabetes Management.

“I think it’s helpful to educate yourself about the side effects before you begin taking metformin, as some doctors tend to gloss over them, but also keep in mind that your body should adjust with time. If it doesn’t, you may want to consider other options with your doctor’s guidance.”

Kat Schroeder, metformin user (read about Kat’s experience with metformin)

Metformin isn’t fitting into your lifestyle 

If you’ve been struggling to remember to take your metformin pill daily or sometimes twice daily, are inconsistent with your dose, or find it a hassle, it may be time to find an alternative medication that doesn’t need to be taken so often. 

Talk with your doctor about finding an alternative, such as a GLP-1 agonist like Trulicity (dulaglutide) or Ozempic (semaglutide). Both are injections that need to be taken only once weekly. 

Your health insurance no longer covers it 

While metformin is reasonably priced with health insurance and is widely covered, if your health insurance changes or you become uninsured, you may not want to pay the price of it over the counter, which can become expensive in the United States. 

Make sure that all your medications are covered on any new health insurance plan you sign up for, and if they’re not and the over-the-counter price is prohibitive, talk with your doctor about finding more affordable alternatives. 

Your health and blood sugar management has improved and you no longer need it 

Taking metformin, in addition to eating a balanced diet and exercising regularly, can be a great jump-start to a healthier lifestyle, better blood sugar levels, and lower weight. 

So can you stop taking metformin when your blood sugar is back to normal? 

After a while, some people may find that they won’t require medication any longer to manage their diabetes (a state known as diabetes remission), and doctors may wean them off metformin. 

Achieving diabetes remission is excellent progress. But always talk with your doctor before weaning yourself off metformin to confirm that you are indeed in remission. It’s possible that taking the medication is the reason your blood sugar levels are staying in range, and stopping will cause them to rise again.

When can you stop taking metformin? 

Metformin takes a few weeks to become fully effective, so if you’ve just started taking the medication, you’ll need to give it some time to work. 

Many people see lower blood sugars within a few weeks of starting metformin therapy, but for weight loss and lower A1c levels, it can take a few months for results to be noticeable. 

Unless you are experiencing debilitating side effects, it is usually best to give the medication some time to take effect. 

Risks of stopping metformin

If you stop taking metformin suddenly, your health may suffer. You may experience side effects such as higher blood sugars, an increased A1c, and even weight gain. 

Over time, higher blood sugar levels can lead to diabetes complications, including: 

Before stopping metformin, make sure you talk with your doctor about your treatment options and maintain a healthy diet and exercise regularly to keep blood sugars within your target range. 

How can you stop taking metformin? 

Never stop taking any prescribed medication without first talking to your doctor. It is crucial that you are able to effectively manage your blood sugar levels through sustainable approaches first. A doctor will use certain benchmarks to see if it’s appropriate for you to stop taking metformin. 

These include:

  • Having a random blood sugar test of 180 mg/dL or lower
  • Maintaining an A1c of 7 percent or lower
  • Having a fasting or pre-meal blood sugar level of 80 to 130 mg/dL 

Additionally, it is unlikely that your doctor will have you stop taking metformin abruptly, especially if you’ve been on the medication for a long time. 

They will most likely have you wean your dose over time, so your body has time to get used to a lower dose without experiencing negative side effects like high blood sugar or weight gain. 

Your doctor can advise you on tapering techniques and how much you should reduce your dose each week until you are taking none at all. Once you stop taking metformin, it will take about 4 days for the medicine to completely clear from your system.

Read more: How Long Does Metformin Stay in Your System?

What are the alternatives to metformin?

There are a variety of alternatives to metformin. These include injections, oral medications, and lifestyle changes. 

In addition to metformin, the following medicines are currently available in the United States as treatments for type 2 diabetes:


  • Glipizide (brand names Glucotrol, Glucotrol XL)
  • Glimepiride (Amaryl)
  • Glyburide (Glynase)


  • Repaglinide (Prandin)
  • Nateglinide (Starlix)


  • Pioglitazone (Actos)
  • Rosiglitazone (Avandia)

DPP-4 Inhibitors

  • Sitagliptin (Januvia)
  • Saxagliptin (Onglyza)
  • Linagliptin (Tradjenta)
  • Alogliptin (Nesina)

GLP-1 Receptor Agonists

GIP/GLP-1 receptor agonist

SGLT2 Inhibitors

Alpha-Glucosidase Inhibitors

  • Acarbose (generic only)
  • Miglitol (Glyset)

Bile Acid Binding Resins 

  • Colesevelam (Welchol) 

Dopamine Agonist 

  • Bromocriptine (Cycloset) 

Amylin Analog 

  • Pramlintide (Symlin)

Insulin (both basal, or background, insulin therapy and a combination of basal and bolus, or mealtime, therapy)

Increasing your physical activity and following a healthy diet can also be excellent strategies, either alone or in addition to treatment with medicine, especially if these lifestyle changes help you maintain your blood sugar levels within the desired range. 

Eating fewer carbohydrates, quitting smoking, and drinking little to no alcohol can also help you manage your blood sugar levels.

Final thoughts

Stopping metformin requires careful consideration and consultation with your doctor. While this medication is not effective or tolerable for everyone, discontinuing it improperly could lead to elevated blood sugar, weight gain, and an increased risk of diabetes complications. 

Discuss the best approach to safely taper off the medicine with your healthcare provider, considering your individual health needs and any insurance constraints, and explore alternative treatments that better suit your lifestyle and health objectives.

Suggested next article: Everything You Need to Know About Metformin.