Approximately ten percent of Americans have been diagnosed with diabetes, which affects approximately 34.2 million Americans, according to the American Diabetes Association.

The vast majority of these patients - about 31 million - have been diagnosed with Type 2 diabetes.

People with Type 2 diabetes produce insulin, but their bodies do not respond to the hormone. By contrast, Type 1 diabetes is characterized by insufficient insulin production and is not caused or influenced by lifestyle. 


When addressing Type 2 diabetes, doctors often prescribe lifestyle changes, such as eating a healthy diet, losing weight, and getting more exercise, as the first line of treatment. However, some patients find themselves unable to manage their blood sugar levels without medication.


Prescription medications like metformin can help patients with Type 2 diabetes regulate their blood sugar levels, but how long does it take metformin to work?   



What is metformin?


Metformin, a generic drug that is also sold under the brand names Glucophage and Glucophage XR, is used for the treatment of Type 2 diabetes. The medication belongs to a class of drugs called biguanides, which were once used to treat diabetes but are now used primarily for the treatment of malaria.


Metformin has been prescribed to more than 120 million people worldwide and is the most popular Type 2 diabetes medication in the world.  The U.S. Food and Drug Administration (FDA) first approved metformin in 1995, and the medication quickly became extremely popular due to its effectiveness.

Metformin is available in both immediate and extended-release formulas.    



What conditions are treated with metformin?


Metformin is used to treat Type 2 diabetes, which impacts an estimated 31 million Americans. Of the ten percent of Americans who have some form of diabetes, 90 percent of those individuals have been diagnosed with Type 2 diabetes. 


Type 1 diabetes, which is sometimes referred to as juvenile diabetes, is a genetic condition in which the body is unable to produce enough insulin to meet its needs.


The condition is not influenced or caused by lifestyle, and patients with Type 1 diabetes must take insulin daily to regulate their blood sugar. By contrast, people with Type 2 diabetes produce insulin but are unable to use it properly because their bodies do not respond to the hormone.


No matter which type of diabetes a person has, they are unable to properly process the glucose in food and turn it into energy.  Under normal circumstances, the body breaks down food into glucose during digestion and releases it into the bloodstream, causing blood sugar levels to rise.


This triggers the pancreas to release insulin, which directs the body to use the glucose for energy. When the body is resistant to insulin, as is the case in people with Type 2 diabetes, levels of blood sugar in the body are elevated for longer than they should be.


When patients are unable to control their blood sugar levels, they can experience dangerous health effects and complications.


Serious conditions and complications associated with elevated blood glucose levels include:

  • Nerve damage in the feet and hands (neuropathy)
  • Damage to the blood vessels of the eyes (retinopathy)
  • Increased risk of kidney disease
  • Increased risk of heart problems like heart disease



How does metformin work?


Metformin influences the amount of glucose, or sugar, in the blood by working in three different ways: reducing the absorption of glucose by the gastrointestinal tract, decreasing the liver’s production of glucose, and increasing target cell insulin sensitivity.


Because people with Type 2 diabetes already produce enough insulin but are not responsive to it, metformin does not influence the production of insulin in any way. Instead, the drug works by improving the body’s sensitivity and response to insulin. 



How long does it take metformin to work?


Metformin is designed to be a fast-acting medication, but the time it takes for the drug to start working will vary depending on the dose of the medication and the individual patient’s tolerance of side effects associated with metformin.


Most patients will begin to see some effects from metformin within 48 hours of their first dose, with significant improvement being noticed within a week. Small doses of metformin are often prescribed to patients who are new to the medication in order to minimize side effects associated with the drug, and smaller doses will take longer to generate a significant improvement in blood glucose levels.


Many patients are prescribed an initial dose of 500 mg of metformin taken once per day, and this dose is gradually increased until a maintenance dose of 1500 mg is taken each day; patients will notice a significant decline in their blood sugar levels upon reaching 1500 mg per day.


Therefore, it may take several weeks or months before patients notice a significant difference in their blood sugar levels when taking metformin, depending on their starting dose and tolerance of the medication. 



What side effects are associated with metformin?


Metformin is intended for long-term use and is the most commonly prescribed Type 2 diabetes medication in the world, but it also has the ability to cause many side effects.


Studies have shown that metformin has the lowest adherence rate of any Type 2 diabetes medication, and it is believed that the intensity of the side effects associated with the drug are the cause.


Metformin is associated with a long list of side effects, but most of the side effects are common and do not require medical attention.  There are several ways to reduce the number and severity of side effects experienced while taking metformin, as discussed below.


The most common side effects associated with metformin usually do not require medical attention. These include:

  • Diarrhea
  • Bloating not from weight gain
  • Stomach pain
  • Constipation
  • Headache
  • Gas
  • Weight loss
  • Nausea or vomiting
  • Heartburn
  • Unpleasant metallic taste in the mouth


The side effects most commonly experienced while taking metformin include gastrointestinal side effects like diarrhea, nausea, and vomiting. Patients are most likely to experience side effects when they first start using metformin or when their dose of the drug increases. Side effects often disappear or become less intense as the body adjusts to metformin, typically within about two weeks.


Many patients are initially prescribed the immediate release version of the medication because it is less expensive than the extended release version, but the immediate release version of metformin is more likely to cause side effects. Patients who experience side effects while taking the immediate release version of the medication can try switching to the extended release form of the drug or taking their medication with a large meal.  


Although the majority of people who experience side effects while taking metformin will experience common side effects that do not require medical attention, metformin is also associated with serious side effects that require immediate medical attention. Although rare, these side effects have occurred on occasion. Lactic acidosis, low levels of iron in the blood (anemia), and low blood sugar (hypoglycemia) are the most serious side effects caused by metformin; each of these side effects requires immediate medical attention.







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