Buy Metformin tablets online for type 2 diabetes

Metformin is a biguanide that can treat or prevent type 2 diabetes. Metformin helps lower your blood sugar levels and improves your body’s response to insulin.

Our prices

Medicine Strength Quantity Price Stock
Metformin500mg56 tablets£14.99In Stock
Metformin SR500mg56 tablets£19.99In Stock
Metformin500mg84 tablets£19.99In Stock
Metformin500mg112 tablets£24.99In Stock
Metformin SR500mg112 tablets£29.99In Stock
Metformin850mg56 tablets£15.99In Stock
Prices exclude a prescription fee. This treatment requires a quick online consultation,
which a doctor will review to determine if a prescription is appropriate.

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Virginia Chachati

Reviewed by Virginia Chachati MPharm
(2013, University College London)
GPhC Registration number: 2087654

Information last reviewed 08/06/2021


What is Metformin?

Metformin is a biguanide which is an antidiabetic medicine. It is used to prevent or treat type 2 diabetes by regulating your blood sugar levels. Metformin is sometimes used to treat polycystic ovary syndrome (PCOS).

What does Metformin do?

Metformin lowers your blood sugar levels and helps improve your body’s response to insulin. Insulin, normally produced by your pancreas, is a hormone that helps your body take glucose (sugars) from the bloodstream and into its cells to use as a source of energy. In type 2 diabetes, the insulin produced by the body cannot work effectively, leading to constant high blood sugar levels. Metformin helps to regulate this process.

How does Metformin work?

Metformin acts by increasing the sensitivity of muscle cells to insulin, helping your body to absorb and use sugar as an energy source. Metformin also slows down the production of sugar in the liver and slows down the rate sugar is absorbed into the bloodstream from your small intestine. Therefore, metformin helps regulate and control the level of sugar in your blood.

How long does Metformin take to work?

Metformin will start to work within 48 hours after first taking it. In some cases, it can take four to five days to start working. Metformin slow release tablets have a gradual effect and are slowly absorbed into the bloodstream.

Metformin for PCOS

Polycystic ovary syndrome (PCOS) is thought to affect one in five women. It causes irregular ovulation, overproduction of male hormones and enlarged ovaries. PCOS can make it difficult to get pregnant and may also produce excess body hair, cause hair thinning, acne and oily skin. It's very common for women with PCOS to have high insulin levels, with a risk of developing type 2 diabetes later in life. Metformin helps to regulate the level of insulin in the blood but it can also work to regulate ovulation and regulate the menstrual cycle. Metformin is an off-label treatment for PCOS and is not usually given in the first instance unless you already have, or are showing signs of, diabetes. 

Please note: Dr Felix only provides a repeat supply of Metformin for patients with type 2 diabetes. If you need Metformin for PCOS, please speak to your doctor.

Metformin for diabetes

Metformin is a treatment for type 2 diabetes and helps control blood sugar levels. A doctor can prescribe metformin for people with type 2 diabetes if it’s not possible to manage their diabetes through diet and exercise alone.

How effective is Metformin?

Metformin is the most commonly prescribed medicine for type 2 diabetes and has proven to be very effective in managing the condition. Studies have shown that patients who are prescribed metformin, when diagnosed early, are unlikely to need additional treatments to control their blood sugar levels.


Active ingredients

The active ingredient in metformin tablets is metformin hydrochloride.

Inactive ingredients

The inactive ingredients in metformin tablets are candelilla wax, cellulose acetate, hypromellose, magnesium stearate, polyethylene glycols (PEG 400, PEG 8000), polysorbate 80, povidone, sodium lauryl sulfate, synthetic black iron oxides, titanium dioxide and triacetin. 

Please Note: Different generic brands of metformin tablets may contain different inactive ingredients. Please check the patient information leaflet for full details

Which ingredients can cause an allergic reaction?

Although it is uncommon, metformin may cause allergic reactions in some people taking the medication. It is always important to know what the signs of an allergic reaction are and look out for them. These include struggling to breathe, swelling of the face or lips, severe dizziness and a skin rash/hives. You should seek immediate medical attention if you're experiencing an allergic reaction.


How to take Metformin?

Always follow your doctor's instructions on how to take metformin as the dose will vary depending on your diagnosis. You should take metformin with or after food. Swallow the tablet whole with a full glass of water. It's common to start taking one or more tablets of metformin each day and gradually increase the number of tablets you need to take each day over the course of a few days or weeks.

Why should I take Metformin after a meal?

You should take metformin with or after a meal as this helps to reduce the chance of side effects. Taking metformin on an empty stomach may result in you feeling nauseous or having stomach problems.

Side Effects

Metformin side effects

Common side effects of metformin include: 

  • Nausea 
  • Vomiting 
  • Diarrhoea 
  • Abdominal pain
  • Lack of appetite
  • A metallic taste in your mouth

Rare side effects of metformin may include: 

  • Lactic acidosis 
  • Vitamin B12 deficiency
  • Skin rash 
  • Itching or flushing of the skin 
  • Inflamed liver


Metformin is not suitable for everyone. Speak to your doctor if any of the following apply to you: 

  • You are allergic to metformin 
  • You've had an allergic reaction to other medicines in the past
  • You have problems with your liver or kidneys 
  • You have a severe infection 
  • You have recently had a heart attack
  • You are being treated for heart failure 
  • You have severe circulation problems 
  • You have difficulty breathing 
  • You drink large amounts of alcohol  
  • You are scheduled to have surgery
  • You are having an x-ray or scan where iodine is injected into the blood

Drug interactions

Certain medicines may interact with metformin. If you are taking any of the following then your blood sugar levels may need to be monitored more regularly: 

  • Water tablets (diuretics)
  • Steroids 
  • Treatments for high blood pressure
  • Treatments for heart problems 
  • Hormone treatments 
  • Additional treatments for diabetes 

If you are taking any other medicines, including herbal remedies or supplements, then always tell your doctor about them before you start taking metformin.

How to cope with Metformin side effects?

After you take metformin, you may experience nausea as a side effect. In this case, your doctor may recommend a smaller dose to begin with, which you will gradually increase over a couple of weeks. This gives your body time to get used to taking metformin and should reduce the likelihood of side effects. Take metformin with food and drink frequent sips of water, especially if you have vomiting or diarrhoea. Sugar free gum can help to reduce a metallic taste in your mouth.

Will Metformin cause hypoglycaemia?

Hypoglycaemia, or a low blood sugar level, is a possible side effect of taking metformin. This is not common and more likely to happen when metformin is combined with other medicines to treat diabetes. Feeling dizzy, tired and hungry are signs that your blood sugar level is low, although the symptoms may vary from person to person.

Will Metformin affect my contraception?

Metformin will not affect how your contraceptive pill works. However, if you are starting the pill, while taking metformin, then let your doctor know as your dose may need to be adjusted.

Metformin and alcohol

You can drink alcohol while taking metformin, but you should check your blood glucose levels regularly as alcohol can cause them to drop dangerously low. Avoid drinking alcohol on an empty stomach. Ideally, you should discuss your alcohol intake with your doctor.

Metformin and pregnancy

Metformin is safe to use during pregnancy and for women who are breastfeeding.

Does Metformin affect your blood pressure?

Metformin is unlikely to affect your blood pressure directly. As metformin targets your blood sugar levels, regular use can lead to weight loss and a lower blood pressure over time.

Treatment Options

Metformin vs. Metformin SR

Metformin SR is a slow release version of metformin. It is normally recommended by your doctor if you experience side effects with standard (immediate release) metformin tablets. With metformin SR, metformin is released gradually into the bloodstream, therefore you take it less often than standard metformin tablets.

Metformin vs. Diaformin

Diaformin is a brand of metformin and contains the active ingredient metformin hydrochloride. However, Diaformin is not available in the UK, only in Australia.

Metformin vs. other diabetes treatments

Metformin is one of the most effective treatments for type 2 diabetes and is usually prescribed by a doctor when a balanced diet and exercise are not enough to control your blood sugar levels. You may be prescribed additional medicines to further control your blood sugar levels if needed. These include: sulfonylureas, meglitinides, thiazolidinediones, DPP-4 inhibitors, GLP-1 receptor agonists, SGLT2 inhibitors and insulin therapy. Some medicines may be more suitable for people with other conditions such as heart, liver or kidney problems. Insulin therapy is usually given as a last resort when other treatments are unable to control your blood sugar levels.

Lifestyle changes to help diabetes

Lifestyle changes can help manage your blood sugar levels as a type 2 diabetic. This includes eating a healthy diet and exercising regularly. Maintaining a healthy weight, quitting smoking and cutting down on alcohol are all positive changes that can help control your blood sugar levels.

Lifestyle changes to make when taking Metformin

Metformin will help manage your type 2 diabetes alongside a healthy diet and regular exercise. Keep in mind that the foods you eat can affect your blood sugar levels. For example, switching to whole grain pasta and bread instead of white carbohydrates can reduce the likelihood of your blood sugar levels spiking or getting too high. Smoking and drinking large amounts of alcohol can also have an adverse affect on your insulin levels. Try to drink less than 14 units of alcohol per week and have alcohol free days in between the days you drink.


Why is Metformin only used to treat type 2 diabetes?

Metformin can help treat type 2 diabetes to effectively regulate constant high blood sugar levels due to a lack of response to the insulin your body produces, also known as insulin resistance. In contrast, type 1 diabetics do not produce enough insulin and therefore require regular insulin injections to control their blood sugar levels.

Is Metformin a cure?

Metformin is not a cure for type 2 diabetes. Taking metformin helps manage type 2 diabetes and improve your quality of life.

How safe is Metformin?

Your doctor will decide if metformin is safe for you to use by looking at your medical history and symptoms. If you have liver, kidney or heart problems, metformin may not be suitable for you.

Is Metformin safe for long term use?

Metformin is safe for long term use, under the guidance of your doctor.

Can I take Metformin before surgery?

Your doctor will advise you on the steps you need to take to prepare for surgery. Generally, you may need to stop taking metformin a few days before surgery.

Can I buy Metformin over the counter in the UK?

Metformin is currently only available via prescription, and is not available over the counter in the United Kingdom.

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