Type 2 diabetes

Diabetes is a lifelong condition that causes a person's blood sugar (glucose) level to become too high. It's important for diabetes to be diagnosed as soon as possible. This is because it will get worse if left untreated.

Types of diabetes 

The hormone insulin, produced by the pancreas, controls the amount of glucose (blood sugar) in the blood. Glucose is an important source of energy for the body.

There are two main types of diabetes:

  • type 1 – where the pancreas doesn't produce any insulin
  • type 2 – where the pancreas doesn't produce enough insulin or the body's cells don't react to insulin

Type 2 diabetes is often associated with obesity and tends to be diagnosed in older people. It's more common than type 1 diabetes.

Another type of diabetes, known as gestational diabetes, occurs in some pregnant women and tends to disappear after birth.

Symptoms of type 2 diabetes 

The symptoms of diabetes occur because the lack of insulin means glucose stays in the blood and isn't used as fuel for energy.

Your body tries to reduce blood glucose levels by getting rid of the excess glucose in your urine.

Typical symptoms include:

  • feeling very thirsty
  • passing urine more often than usual, particularly at night
  • feeling very tired
  • weight loss and loss of muscle bulk

These signs and symptoms aren't always obvious, however, and it's often diagnosed during a routine check-up.

This is because they are often mild and develop gradually over a number of years. This means you may have type 2 diabetes for many years without realising it.

See your GP if you think you may have diabetes.

Diagnosing type 2 diabetes

It's important for diabetes to be diagnosed early. This is so treatment can begin as soon as possible.

If you experience the symptoms of diabetes (see above), see your GP as soon as possible. They'll ask about your symptoms and may ask for blood and urine tests.

Your urine sample will be tested for glucose. Urine doesn't normally contain glucose. However, glucose can overflow through the kidneys and into your urine if you have diabetes.

If your urine contains glucose, a specialised blood test known as glycated haemoglobin (HbA1c) can be used to find out whether you have diabetes.


The pancreas is a large gland behind the stomach. Type 2 diabetes occurs when the pancreas can’t produce enough insulin to control your blood glucose level, or when the cells in your body don't respond properly to the insulin that is produced.

This means your blood glucose levels may become very high. This is known as hyperglycaemia.

Hyperglycaemia can occur for several reasons, including:

  • eating too much
  • being unwell
  • ineffective diabetes medication, or not taking enough

Hyperglycaemia causes the main symptoms of diabetes (see above). These include extreme thirst and frequent urination.

Causes of type 2 diabetes 

Type 2 diabetes occurs when the body doesn't produce enough insulin to function properly, or the body's cells don't react to insulin. This means glucose stays in the blood and isn't used as fuel for energy.

Risk factors for type 2 diabetes 

Three of the main risk factors for developing type 2 diabetes are:

  • age – being over the age of 40 (over 25 for people of south Asian, Chinese, African-Caribbean or black African origin, even if you were born in the UK)  
  • genetics – having a close relative with the condition, such as a parent, brother or sister
  • weight – being overweight or obese

People of south Asian and African-Caribbean origin also have an increased risk of developing complications of diabetes, such as heart disease, at a younger age than the rest of the population.

Treating type 2 diabetes 

Treatment for diabetes aims to keep your blood glucose levels as normal as possible and to control your symptoms. This is to prevent health problems developing later in life.

If you've been diagnosed with type 2 diabetes, your GP will be able to explain your condition in detail to help you understand your treatment. You will be given advice on diet and exercise in order to improve control of your blood glucose.

For some people this will be enough to control the blood glucose; others may need to start on medication (tablets).

They'll also closely monitor your condition to identify any health problems that may occur. If there are any problems, you may be referred to a hospital-based diabetes care team.

As type 2 diabetes controlled by diet and exercise usually gets worse; you may eventually need medication. This is usually tablets to keep your blood glucose at normal levels. Some patients with more severe type 2 diabetes may require insulin injections.

Complications of type 2 diabetes 

Short term problems can occur if your blood sugar is too low, causing hypoglycaemia, or ‘hypos’. If your blood sugar is too high, you can develop a condition called ketoacidosis. Both conditions are serious, and can lead to hospital admission. It is less likely in type 2 diabetes, than it is in type 1 diabetes, that ‘hypos’ or ketoacidosis will occur.

Diabetes can cause serious long-term health problems. It's the most common cause of vision loss and blindness in people of working age.

Everyone with diabetes aged 12 or over should be invited to have their eyes screened once a year for diabetic retinopathy (eye disease that could affect their vision).

Diabetes is also responsible for most cases of kidney failure and lower limb amputation, other than accidents.

People with diabetes are up to five times more likely to have circulatory disease, such as a stroke or heart problems, than those without diabetes.

Other effects of poorly controlled diabetes include loss of sensation, skin ulceration, and increased risk of infection. Good control of blood glucose is essential in order to avoid complications, and promote a normal life expectancy.

Preventing type 2 diabetes 

If you're at risk of type 2 diabetes, you may be able to prevent it developing by making lifestyle changes.

These include:

Living with type 2 diabetes 

If you already have type 2 diabetes, it may be possible to control your symptoms by making the above changes. This also minimises your risk of developing complications.

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was reviewed January 2019

This page is due for review December 2020

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