The symptoms of diabetes include feeling very thirsty, passing more urine than usual and feeling tired all the time.

The symptoms occur because some or all of the glucose stays in your blood and isn’t used as fuel for energy.

Your body will try to get rid of the excess glucose in your urine.

The main symptoms, which are common to both type 1 diabetes and type 2 diabetes, are:

• urinating more often than usual, particularly at night
• feeling very thirsty
• feeling very tired
• unexplained weight loss
• itching around the penis or vagina, or frequent episodes of thrush
• cuts or wounds that heal slowly
• blurred vision (caused by the lens of the eye becoming dry)

The signs and symptoms of type 1 diabetes are usually obvious and develop very quickly, often over a few weeks.

The signs and symptoms of type 2 diabetes aren't always as obvious, and it's often diagnosed during a routine check-up. This is because the symptoms are often mild and develop gradually over a number of years.

This means that you may have type 2 diabetes for many years without realising it.

Early diagnosis and treatment for type 2 diabetes is very important because it may reduce your risk of developing complications later on. Visit your GP as soon as possible if you think you may have diabetes.

Hyperglycaemia

Type 2 diabetes occurs when the pancreas (a large gland behind the stomach) 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.

Due to the lack of insulin or its inability to regulate blood glucose, 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 – or not taking enough – diabetes medication 

Hyperglycaemia causes the main symptoms of diabetes, which include extreme thirst and frequent urination.