How fast does metformin lower blood sugar

Metformin is a medicine used to treat type 2 diabetes and gestational diabetes. It's also used to help prevent type 2 diabetes if you're at high risk of developing it.

Type 2 diabetes is a condition where the body does not make enough insulin, or the insulin that it makes does not work properly. This can cause high blood sugar levels (hyperglycaemia).

Metformin lowers your blood sugar levels by improving the way your body handles insulin.

It's usually prescribed for diabetes when diet and exercise alone have not been enough to control your blood sugar levels.

Metformin is also sometimes used to manage symptoms of polycystic ovary syndrome (PCOS), a condition that affects how the ovaries work. It is not officially approved for PCOS.

Metformin treats PCOS by lowering insulin and blood sugar levels. This can also improve ovulation and encourage regular periods, even if you do not have diabetes.

Metformin is available on prescription as tablets, as a liquid that you swallow and as sachets of powder that you dissolve in a drink.

Key facts

  • Not everyone gets diabetes symptoms, so taking metformin may not make you feel any different. That does not mean it is not working, so keep on taking it.
  • It's best to take metformin with a meal to reduce the side effects.
  • The most common side effects are feeling and being sick, diarrhoea, stomach ache and loss of appetite. Vitamin B12 deficiency is also a common side effect of taking metformin in higher doses or for long periods.
  • Metformin does not cause weight gain, unlike some other diabetes medicines.
  • If you have diabetes, you can get free prescriptions for all of your medicines, not just your diabetes ones. You'll need to have a medical exemption certificate.

Page last reviewed: 24 March 2022
Next review due: 24 March 2025

How fast does metformin lower blood sugar
When to Take Metformin, Before or After Meals?

Article in Spanish/Artículo en español

Is metformin a miracle drug? You would think so because it is one of the most popular medications to treat type 2 diabetes, not those with type 1 diabetes. Metformin is also used to manage prediabetes, obesity, and polycystic ovary disease syndrome (PCOS). It is inexpensive compared to other diabetes medications, and it has been on the U.S. market since 1995. One of the most questions I receive is, “when to take metformin, before or after meals?” I have the answer for you in this article. Whether you are just starting to take metformin or have been taking it for a while, I am sure you will find something you did not know.

How fast does metformin lower blood sugar
How long does it Metformin to Work?

How long does it take Metformin to work?

Metformin signals the liver to stop making blood sugar and releasing it into the circulation. This results in lower blood sugar level. Metformin improves how your muscles use insulin making this process much more efficient. This is called insulin sensitivity. Metformin starts working 2 days after taking it and you will see your blood glucose (sugar) drop 4-5 days later. A 1000mg dose of metformin can decrease an A1C level up to 2% over a 3-month period. A1C or hemoglobin A1C is a 3-month average of blood glucose level. For example, if your A1C was 10%, it may drop to 8% in 3 months.

How fast does metformin lower blood sugar
How Long does Metformin Stay in your System?

How long does Metformin Stay in your System?

Metformin reaches the highest concentration in the blood (peak concentration) 1-3 hours after taking the pill. The half-life of metformin is 2-6 hours. Half-life of a drug is the time it takes for the concentration of a drug to be reduced by 50%. However, the half-life may take up to 14 hours. The time metformin stays in your system varies. For example, a slower metabolism will cause metformin to stay longer in your system; the amount of metformin and how long you have taken it; older individuals may have a longer elimination rate and if you are an individual with higher weight, the medication will stay in your body longer.

How fast does metformin lower blood sugar
Types of Metformin

Types of Metformin

You can find metformin under the following names:

  • Glucophage
  • Glucophage XR
  • Glumetza
  • Fortamet

While metformin is an effective diabetes medication, it may cause digestive problems such as

  • Stomach upset
  • Diarrhea
  • Nausea
  • Bloating

The extended release (ER) version improves stomach discomfort. However, ER is more expensive than immediate release (IR). If you can’t afford your medication, contact the company and ask about prescription savings programs.

In 2020, the Food and Drug Administration announced that nitrosamine impurities were found in certain metformin release products. Several companies voluntarily recalled their extended-release metformin.

Dosages of Metformin

There are many forms and dosages of metformin for adults with diabetes

Immediate-release tablets:

  • 500 mg
  • 850 mg
  • 1000 mg

Extended-release (XR) tablet and liquid form

  • 500 mg
  • 750 mg
  • 1000 mg

Most doctors prescribe 500mg once or twice daily. Two weeks later, your dose may increase (1500mg-2500mg/day) until your blood glucose reaches its target level. You may need other medications besides metformin to get your blood sugar levels to target.  It doesn’t mean your diabetes is getting worse. Metformin targets the liver and other medications target other organs. A combination of one or two medications is common.

How fast does metformin lower blood sugar
When to Take Metformin, Before or After Meals?

Don’t let digestive side effects dissuade you from taking metformin. Not everyone has stomach discomfort, and it may go away after a few weeks of treatment. So, when should you take metformin, before or after meals? You should always take metformin after finishing your meal. Extended-release metformin can also help to reduce an upset stomach. If the symptoms do not disappear after a few weeks, ask your doctor before stopping metformin.

What is Metformin Induced Lactic Acidosis?

This is a rare and profoundly serious condition in individuals who take metformin when they have severe kidney or liver disease, dehydration, or acute/unstable heart failure. The signs of lactic acidosis are

  • Fatigue
  • Weakness
  • Muscle pain
  • Drowsiness
  • Stomach pain
  • Irregular heartbeat.

Ask your doctor if you have kidney disease.

How fast does metformin lower blood sugar
Metformin and vitamin B12

Metformin and Vitamin B12

Metformin may lower your vitamin B12 levels, especially if you are taking it for a long period of time. Vitamin B12 helps prevent megaloblastic anemia, a type of anemia where red blood cells are unusually large and abnormal. Vitamin B12 also

  • Makes DNA (your genetic footprint)
  • Maintains nerve and blood cells healthy

B12 deficiency causes

  • Constipation
  • Weight loss
  • Poor appetite
  • Tiredness
  • Weakness
  • Numbness
  • Tingling
  • Depression
  • Poor balance
  • Confusion
  • Dementia
  • Tongue and mouth soreness.

Vitamin B12 is only found in animal foods and added to some fortified foods, such as some breakfast cereals and nutritional yeast. Take a Vitamin B12 supplement if you are vegan. Your doctor can order a laboratory test of your vitamin B12 levels.

How fast does metformin lower blood sugar
Can Metformin Cause Hair Loss?

Can Metformin Cause Hair Loss?

Hair loss or alopecia is becoming more common in women. Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder causing:

  • Irregular periods
  • High blood sugar (Your cells don’t respond well to insulin.)
  • Excess weight
  • Type 2 diabetes
  • High cholesterol
  • Heart disease

PCOS may cause hair loss. Metformin is prescribed for women with PCOS therefore hair loss results from PCOS, not metformin. Vitamin B12 deficiency prevents hair follicles from receiving oxygenated blood, leading to hair loss. Taking metformin for a long time can cause Vitamin B12 deficiency. If you are losing your hair or your hair is thinning, ask your doctor to test your vitamin B12 and iron levels.

Now that we’ve covered some basics of metformin, let’s bust a few myths and address common questions and concerns.

Metformin Myths

 Metformin prevents a computer tomography (CT) scan with contrast

Current recommendations do not support a need to discontinue metformin before a CT scan using contrast in persons with mild to moderate renal failure. If you have severe kidney impairment, you may need to discontinue metformin for the 48-hours before the test. Your health care team will provide instructions.

 Metformin raises cholesterol levels

Metformin has been shown to improve total cholesterol, lower LDL cholesterol, the lousy or bad cholesterol and lower triglycerides (fats in the blood).

Metformin is dangerous for pregnancy

Using metformin in pregnancy has not shown to affect the newborn’s development.

How fast does metformin lower blood sugar
Metformin and Kidneys

Metformin and kidneys

Your doctor will check your kidney function before prescribing metformin. Your doctor will test your estimated glomerular filtration rate (GFR). GFR measures how effective are your kidneys in removing waste and excess fluids from your body. Metformin is contraindicated in severe reduction in GFR.

How fast does metformin lower blood sugar
Common Questions and Concerns

Common Questions and Concerns

Is my metformin dose (Glucophage 500mg) too high?

Metformin’s minimum daily dose is 500 mg a day and the maximum daily dose is 2500 mg. Your dose depends on your

  • Health status
  • Blood glucose level
  • Age
  • Medical conditions.

Your doctor will prescribe a lower dose and slowly increase the dose until it reaches 1500mg-2500mg daily.

What is the benefit of taking metformin at night?

Take metformin as prescribed by your doctor. If you only take one dose, it is preferable to take it at night after your meal to decrease side effects such as nausea, bloating, or diarrhea. If you are taking 2 doses, take it after meals.

Will I ever come off metformin, or will I become dependent on it?

Metformin is not addictive. Diabetes is a progressive chronic condition and when metformin is no longer effective at lowering blood glucose, another medication may be added, or you may be taken off metformin completely.

Does metformin cause a change in taste?

Metformin is excreted in the saliva causing changes in taste. Some people taking metformin report a metallic taste in their mouths. After some time, this aftertaste will disappear.

Metformin and alcohol: Can I still drink alcohol when taking metformin?

Drinking excessively (binge drinking or frequently) while taking metformin may increase the risk of lactic acidosis. You may be at higher risk of lactic acidosis if you have kidney or liver disease, unstable congestive heart failure or dehydration.

Why does metformin smell like fish?

Some people complain there is a strong fish smell prompting them to think their pills are no good. The medical literature does not report any information about the odor in metformin. If this is of concern, speak with your pharmacist and your doctor. There are no reports that the odor affects the effectiveness of the medication. Do not stop taking it without notifying your healthcare team.

Can metformin increase my chances of becoming pregnant?

Yes. Metformin can help you lose weight and increase insulin sensitivity causing you to ovulate regularly and increase your chances of becoming pregnant.

How much does metformin lower blood sugar? Will I go too low?

Metformin can lower your A1C as much as 1.5%. For example, an A1C of 9% (estimated blood glucose of 210 mg/dl) can decrease to 7.5% (~169 mg/dl). The risk of hypoglycemia is low if you only take metformin because it does not stimulate insulin secretion. Vigorous physical activity and skipping meals may cause hypoglycemia.

Do you need help managing your blood sugar?

If you find yourself with high blood glucose in the morning or your blood sugar is like a roller coaster, I can help you! Schedule a free consultation with me and ask me your most pressing question. Make an appointment today. Click here

Article in Spanish/Artículo en español

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How much does metformin 500mg lower blood sugar?

Metformin is very effective at controlling blood glucose and lowers A1c levels by as much as 1.5% at maximum doses.

How long does 500mg of metformin last?

Official answer. Metformin (brand name: Glucophage) will be in your system for 96.8 hours which is approximately 4 days. Metformin has an elimination half-life of approximately 17.6 hours.

Can metformin alone lower blood sugar?

Using metformin alone, with a type of oral antidiabetic medicine called a sulfonylurea, or with insulin, will help to lower blood sugar when it is too high and help restore the way you use food to make energy. Many people can control type 2 diabetes with diet and exercise.

How will I know if metformin is working?

A medical provider can run a few tests to see how metformin is affecting your health: Blood work can check if your glucose, insulin, and HbA1C levels are in range. If they are, the medication is working.