How Long Does It Take For Metformin To Work? (Side Effects & How Metformin Works)

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Metformin works by reducing the glucose formed in the body. Therefore, intake should begin low and increase gradually to optimum levels. It takes up to 48 hours for Metformin to work. However, you will receive more effective results within four to five days after taking this blood sugar regulating medicine.

People who have type 2 diabetes or diabetes mellitus may be advised by their doctor to start taking Metformin, especially when diet regulation and physical exercise fail to yield beneficial results.

When suffering from type 2 diabetes, your body cannot produce the hormone insulin or finds it hard to use the insulin that gets made. The hormone insulin’s main function is to move sugar produced by the food we eat into the cells to be stored or directly into the blood to be used as energy.

The failure in insulin functionality thereby results in excessive sugar in the blood; a condition medically referred to as hyperglycemia which eventually leads to diabetes.

Diabetes can affect you for a lifetime and cause strokes, liver failure, heart failure, and even blindness.

Metformin comes from a group of drugs known as biguanides and works by regulating the amount of glucose or sugar in the blood, unlike some other medications used to increase and regulate the hormone insulin.

How Metformin works

Metformin works in three major ways. First, it inhibits enzymes in the liver, which break down carbohydrates into glucose, which means less sugar will be stored or passed into the body.

As nutrients flow in the small intestines, they are absorbed into the bloodstream. Glucose is also absorbed in this stage. Metformin also prevents this absorption, ensuring only a minimal amount of sugar is absorbed in the bloodstream while the rest is passed as waste.

And thirdly, Metformin helps the body’s cells be responsive to insulin, thus making it possible to move blood sugar from the blood into the cells where it is used as needed to produce energy.

All these changes take up to five days to get effective. However, a patient may experience symptomatic relief within 48 hours of taking Metformin.

How to use metformin

Unlike many drugs, you must not jump right into a maximum metformin dosage.

Those who try may experience quite strong side effects like severe gastric disturbances. Therefore doctors have devised a proper method to allow the body to acclimatize to the drug gradually.

You may be requested to use a minimum dosage of, say, 500 grams per day, and the amount would then be increased gradually to reach the optimum amount of 1500 grams a day.

But that method does not guarantee that you will not experience any side effects, only that they will be less severe and easy to handle.

It may also mean by the time you are ready to take a full dosage, you may have learned how to balance your medicines and diet in a way that assures of no side effects whatsoever.

Some side effects of metformin

Here are some side effects of Metformin, you need to know first.

1. Lactic acidosis

Lactic acidosis may be one of the rarest side effects of metformin usage. However, you may elicit this emergency level side effect when you use excessive metformin or engage in excessive alcohol intake.

The condition causes a buildup of lactic acid in the body. The lactic acid lowers the pH of the blood and makes it more acidic.

Before long, you may begin to experience confusion, jaundice, and difficulty breathing, among many other symptoms. Lactic acidosis requires emergency response since it can be fatal.

2. Hypoglycemia

Too much intake of metformin can cause hypoglycemia or low blood sugar. Low blood sugar begins when it goes below 70 mm/dl.

Consequently, you may feel hungry and experience a fast heartbeat, sweating, headache, fatigue, and confusion.

An older man is sitting down after feeling irregular and fast heartbeats and is now calling his doctor

Those who combine metformin usage with insulin intake or excessive alcohol usage may also happen to those who combine it with insulin intake.

Therefore, such people must always have a blood glucose monitor and check their levels regularly, especially when they begin to feel low.

The best way to reverse hypoglycemia is to intake sugary snacks and usage of glucose tabs.

3. Vitamin B12 deficiency

Vitamin B12 cuts across as an essential vitamin used to produce red blood cells, nerves, and DNA, not to forget many other functions in the body. Metformin inhibits the absorption of vitamin B12 into the body leading to its deficiency.

Vitamin B12 deficiency means fewer red blood cells and thus anemia, a very dangerous condition. You may also suffer from nerve problems like the pins and needles sensation on your hands and legs.

Therefore your doctor may advise you to use some vitamin B12 substitute when using metformin.

4. Faux low

People taking metformin for the first time may experience a faux low. When your blood sugar has consistently been high for some time, it goes down to the normal range after taking metformin.

Given that your body has become accustomed to high blood sugar, you may feel like you are experiencing hypoglycemia when it drops to normal.

However, every diabetic person has a unique blood sugar threshold and different symptoms of faux low when it comes to that. The most common may be irritability, shaking, tiredness and dizziness.

You should confirm this feeling with your blood sugar monitor when you experience this type of feeling.

Once you confirm that the low is false, you should continue taking your metformin as directed and avoid taking anything that may spike your blood sugar level.


How much does metformin lower blood sugar?

Metformin gets prescribed and taken in dosages designed to bring blood sugar to normal levels, since going below 70 mm/dl may cause hypoglycemia.


First, I always advise everyone to avoid over-the-counter medication when it comes to medicine. If you want to begin with metformin, get a prescription from a doctor.

Second, increase the dosage slowly and avoid using metformin with other drugs without medical advisement from a doctor.

Finally, avoid excessive alcohol consumption since it can cause fatal side effects like lactic acidosis and observe all necessary dosage instructions.

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Nudrat Naheed
Hi, I am Nudrat, The Heart And Brain author, IR student, and painter. Writing about health fascinates me because it helps me to explore a new healthy routine and share it with others. I write primarily about general health, pregnancy, postpartum, and allergies here. If you don't find me writing, I'm busy painting or reading on global politics.

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