Here’s What You Should Do When Metformin Stops Working For You

Diabetes is a medical condition that is progressive and chronic in nature; which means that if the patient does not seek treatment, then it worsens with time.

Metformin is a medication taken orally for treatment of type 2 diabetes along with lifestyle modifications. When your metformin is not working as it used to or does not have the same effect on your sugar levels like before, then change in the treatment plan is often recommended by the doctor. Let’s find out what you should do when your metformin stops working for you.

How Long Does Metformin Take To Be Effective?

Metformin does not give instant results, such as it does not immediately decrease your blood sugar levels.

Metformin usually starts to be effective in about 48 hours or 2 days of taking it and it shows considerable effects after taking it for 4 to 5 days. Point to remember is that the time taken for metformin to work or be effective depends on the dose the patient is taking.

If your metformin is not working for you or is not as effective as before, even with exercise and dietary changes; then your doctor can increase the metformin dose to see if it has any effect on your sugar levels or can prescribe medications to be taken along with metformin.

How Does Metformin Decrease Your Sugar Levels? (2)

How Does Metformin Decrease Your Sugar Levels

Metformin decreases your sugar levels by:

  • Decreasing the sugar absorption throughout intestines.
  • Improving the efficacy of insulin hormone.
  • Decreasing the production of sugar by the liver.

In order for Metformin to be effective, the patient should also diligently follow exercise and proper diet as recommended by their physician.

How to Find Out the Efficacy of Metformin in Diabetics?

Patients should regularly check their blood glucose/sugar levels to know if the metformin is working for them or not. Other than this, your doctor will also check the patient’s vitamin B12 to find out the efficacy of the metformin.

Why Checking Vitamin B12 Levels Is Important In Diabetes? (4)

Metformin can cause deficiency of the vitamin B12 depending on its dose.(3, 4) Other risk factors contributing to vitamin B12 deficiency are:

  • The use of certain medications along with metformin.
  • Consuming only a plant-based diet.(5,9,10)
  • If you have had a bariatric surgery that in turn hinders the absorption of vitamin B12 by the body.(6,7,8)
  • More checkups are needed if there is a concern regarding deficiency of vitamin B12.

What is the Purpose of Glycated Hemoglobin (HbA1c) In Regards to Metformin Efficacy? (11, 12, 13, 14)

Glycated hemoglobin (HbA1c) levels are checked to monitor your sugar levels and to see how well metformin is working for you.

Checking HbA1c levels helps in showing the average of blood sugar levels in the past two to three months. The blood sample for testing HbA1c levels is taken from a vein. The desirable HbA1c for diabetic patients is lesser than 7%. The levels can vary depending on the age of the patient and other things.

If the HbA1c is not within the desired range, then the treatment will be changed by the doctor.

What You Should Do When Your Metformin Is Not Working And Your Blood Sugar Remains High? (15, 16)

If you feel that your metformin is not working for you, then what you should do is inform your doctor immediately.

Just taking metformin is not enough. For treating diabetes, it is very important to follow a healthy diet along with regular exercise.(15) When a patient is suffering from type 2 diabetes, it becomes even more imperative in order to get the desired efficacy from metformin to change your diet and add exercise to your daily routine.(16)

Some diabetics can control their sugar levels just by regular exercise and dietary changes without the use of any medicine. However, if these do not work for you, then you need medication to keep your diabetes in check.

The following rules should be followed to keep the blood sugar levels in control and for metformin to work:

Exercise is a Must if You Want Your Metformin to Work Effectively (17)

  1. Exercise increases insulin sensitivity, which then helps in removal of the sugar from the body more effectively. This sensitivity to insulin can be present for as much as 24 hours, depending on the workout duration and other factors.
  2. When you are exercising, the cells of the muscle utilize sugar as fuel and as the sugar get burned in this manner, the need for insulin by the body to remove the excess sugar decreases.
  3. That is why; just taking metformin is not enough. The patient also needs to follow the recommended exercise regime by their doctor for metformin to have its maximum effect.

Take Medications According To Your Doctor’s Instructions (18, 19, 20, 21)

  1. Metformin is commonly prescribed as a first-line treatment for type 2 diabetes, along with increased activity levels and clean, sugar free diet.(18)
  2. Metformin takes some time to show its effects and it could be a few weeks to a few months for the doctor to know whether the metformin is working for the patient or not.
  3. There are some medicines, such as insulin and a category of drugs known as sulfonylureas, which can rapidly decrease the blood sugar levels.(19, 20) However, according to a research, there are some side effects of sulfonylureas, such as hypoglycemia, commonly known as low blood sugar.(21)
  4. Always follow your doctor’s advice when starting any medication in the manner of taking. Your doctor knows the best how to take medication to get the maximum efficacy out of it and reduce the side effects as much as possible. Not following doctor’s instructions and going about your way can prove very risky.

Cut Down On Your Carbohydrate Consumption (22, 23)

One of the main contributors to increased blood sugar includes carbohydrates; however, all carbohydrates are not bad for diabetics.

One of the main causes of rapid increase in the blood sugar levels are consuming foods high in the glycemic index. Whereas; consumption of foods with low glycemic index produces less immediate and drastic affects on your sugar levels. So, make sure to consume healthy carbs to keep your blood sugar levels in check.

Follow Fiber Rich Diet (24, 25)

Studies have shown that patients suffering from diabetes or those at increased risk for diabetes need to eat foods that are rich in dietary fiber, like legumes and beans.

This fiber type does not get digested in the small intestine; and hence will not lead to rapid increase in blood sugar levels when compared to foods having less fiber.

When Should You Consult Your Doctor?

When you discover that your blood sugar levels are rising rapidly and your metformin is not being as effective as before, or not working at all, then you need to seek medical attention immediately.

Symptoms of Hyperglycemia or High Blood Sugar (26, 27)

Some of the symptoms of high blood sugar are: increased thirst; frequent urination; nausea; fatigue and dizziness. If you or someone you know are experiencing these symptoms, then it’s time to consult your doctor ASAP.

If appropriate action is not taken; and if the levels of blood sugar continue to rise, then it can lead to a condition known as diabetic ketoacidosis, also referred to as diabetic coma.

Symptoms of Diabetic Ketoacidosis (28)

Common symptoms of diabetic ketoacidosis are: breathlessness, nausea, fruity smelling breath; severe mouth dryness and vomiting.

What are the Side Effects of Metformin? (29)

There are some minor and severe side effects of metformin.

Serious Side Effects of Metformin (29, 30)

Serious side effects of metformin, which need immediate medical attention are: lactic acidosis (accumulation of acid in the blood); cold feet; cold hands; slow and irregular heartbeat; dizziness; weakness; difficulty breathing; tiredness; stomach pain; vomiting and sleepiness

Minor Side Effects of Metformin (29, 31)

Some minor side effects of metformin are: nausea; diarrhea and an upset stomach.

Taking your metformin along with a meal is advised, as this can combat some of the side effects. If the side effects continue to persist, then seek medical advice.

What are the Alternatives to Metformin?

Metformin belongs to the category of drugs known as biguanides.(1) However, as of now, there is no alternative medicine for this group.

Other medications for diabetes include insulin and Sulfonylureas and every medicine works in a different manner.(32)

Depending on your needs, your doctor will decide which diabetes medication is most appropriate for you. Some diabetes medicines are injected. Sometimes, patients prefer to take oral medicines only and do not like to take injected medicines. The patient’s preferences will be taken into account and the doctor will decide on what is best for you in controlling your diabetes.


As mentioned before, the first-line of treatment for type 2 diabetes consists of metformin along with exercise and healthy diet.

In some patients, it can take a few weeks or even months before they can see any improvement in their blood sugar levels. Insulin and sulfonylureas have faster results; however, they also have more risks and side effects.

The best person to advise and explain you about the mechanism and efficacy of diabetes medications along with other methods of reducing blood sugar levels is your doctor. So, please follow your doctor’s advice.

Extremely high level of blood sugar is a medical emergency; to avoid such a situation, patients suffering from diabetes should undergo monitoring on a regular basis and understand the need and the correct time to seek medical attention.



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