Prediabetes: what it is, how to recognise it and what you can do

Many people feel generally fine day to day, maybe a little more tired than usual or noticing some gradual weight gain, but would not suspect anything serious. What often goes unnoticed is that blood sugar levels can already be creeping up behind the scenes. Prediabetes is a condition that rarely causes obvious symptoms, which is exactly why so many people do not realise they have it. It sits in the grey area between normal blood sugar and type 2 diabetes, offering a crucial window of opportunity. The good news is that if you catch it early, there is a real chance to turn things around.

Table of Contents

• What is prediabetes?

• What are the symptoms of prediabetes?

• Blood sugar levels: what do the numbers mean?

• Who is at risk of developing prediabetes?

• What happens if prediabetes is left untreated?

• Can prediabetes be reversed?

• How is prediabetes diagnosed?

• Frequently asked questions about prediabetes

What is prediabetes?

Prediabetes is a condition where blood sugar (glucose) levels are higher than normal, but not yet high enough to be diagnosed as type 2 diabetes. It develops when the body becomes less responsive to insulin, the hormone responsible for moving glucose from the bloodstream into cells for energy.

When you have prediabetes, this process no longer works as efficiently. Instead of being used by your cells, glucose begins to build up in the blood. This can happen because the pancreas does not produce enough insulin, or because the body’s cells become resistant to insulin and do not respond to it properly.

Source: Mayo Clinic, 2023

What are the symptoms of prediabetes?

Prediabetes is often described as a “silent” condition because most people experience no clear symptoms at all. This lack of obvious warning signs is one of the main reasons it frequently goes undetected. A possible sign of prediabetes is darkened skin in areas such as the neck, armpits or groin.

Typical signs that prediabetes may have progressed to type 2 diabetes include:

• Increased thirst

• Frequent urination

• Increased hunger

• Fatigue

• Blurred vision

• Tingling or numbness in the hands or feet

• Frequent infections

• Slow healing sores

• Unintentional weight loss

These symptoms are easy to dismiss or attribute to everyday factors like stress, poor sleep, or a busy lifestyle. Because of this, many people don’t connect them to blood sugar levels.

It’s important to understand that symptoms alone are not a reliable way to identify prediabetes. The only way to confirm it is through a blood test.

Source: Mayo Clinic, 2023 

Blood sugar levels: what do the numbers mean?

Understanding your blood sugar results can help you identify where you stand. The table below shows the typical reference ranges:

Source: Cleveland Clinic, 2025; NHS, 2025; Mayo Clinic, 2023

• Fasting Blood Glucose (mmol/L): Measures your blood sugar at a single point in time after fasting (8-12 hours)

• HbA1c (mmol/mol): Shows your average blood sugar over the past 3 months 

• A1C (%): Same as HbA1c, but expressed as a percentage

Source: National Institute of Diabetes and Digestive and Kidney Diseases, 2020

Keep in mind that reference ranges may vary slightly between laboratories, and results should always be interpreted with a healthcare professional.

Who is at risk of developing prediabetes?

Several factors can increase your risk of developing prediabetes. These are largely the same as those associated with type 2 diabetes and are closely linked to insulin resistance.

These include:

• Being overweight, particularly with excess fat around the abdomen

• A larger waist size

• Low levels of physical activity

• A diet high in red and processed meats or sugar-sweetened beverages

• Age (risk increases from around 35 onwards)

• A family history of type 2 diabetes

• Certain ethnic backgrounds, including Black, Hispanic, American Indian and Asian populations

• A history of gestational diabetes

• Polycystic ovary syndrome (PCOS)

• Sleep conditions such as obstructive sleep apnoea

• Smoking

Other health markers linked to increased risk include:

• High blood pressure

• Low levels of HDL (“good”) cholesterol

• High triglyceride levels

Having one or more of these risk factors does not mean you will definitely develop prediabetes, but it does make monitoring your blood sugar levels more important.

Source: Mayo Clinic, 2023

What happens if prediabetes is left untreated?

If prediabetes is not identified and managed, it often progresses to type 2 diabetes over time. Even before this progression, elevated blood sugar levels can cause long term damage to the body, particularly affecting the heart, blood vessels and kidneys.

Prediabetes has also been linked to silent heart attacks, meaning damage can occur without obvious symptoms. As the condition progresses, the risk of serious health complications increases, including high blood pressure, high cholesterol, heart disease, stroke, kidney disease, nerve damage and vision problems.

The key difference lies in timing. When prediabetes is detected early, there is a valuable opportunity to prevent or delay these outcomes, often through relatively simple lifestyle changes.

Source: Mayo Clinic, 2023

Can prediabetes be reversed?

Yes. Prediabetes is often reversible, which makes early detection so valuable. Unlike type 2 diabetes, it can frequently be managed through lifestyle changes alone.

Effective steps include:

• Eating a balanced, nutritious diet

• Staying physically active on a regular basis

• Losing excess weight if needed

• Keeping blood pressure and cholesterol levels under control

• Avoiding smoking

Medication is not usually required at this stage, as lifestyle interventions are the first-line approach. If you think you may be at risk, it’s important to speak to your GP. Regular monitoring can help you track progress and stay on top of your health.

Source: Mayo Clinic, 2023

How is prediabetes diagnosed?

Prediabetes is diagnosed through a blood test rather than symptoms. The two main tests used are fasting blood glucose (fasting plasma glucose test (FPG))) and A1C test.

A fasting blood glucose test (fasting plasma glucose test (FPG))) measures your blood sugar after not eating for 8-12 hours. The A1C test measures the amount of hemoglobin with attached glucose and reflects your average blood glucose levels over the past 3 months (National Institute of Diabetes and Digestive and Kidney Diseases, 2020).

For added convenience, at-home testing is also available. The Homed-IQ blood sugar test allows you to collect a small blood sample via a finger-prick and send it to an accredited laboratory. You’ll receive clear results with an explanation, helping you understand your status without needing an initial GP appointment.

Frequently asked questions about prediabetes

What is the difference between prediabetes and type 2 diabetes?

Prediabetes means your blood sugar is elevated but not high enough for a diabetes diagnosis. Type 2 diabetes involves consistently high blood sugar that requires ongoing management (CDC, 2024; Mayo Clinic, 2023)..

Can prediabetes go away on its own?

It typically does not resolve without changes. However, with lifestyle improvements, it can often be reversed (CDC, 2024; Mayo Clinic, 2023).

Does prediabetes always develop into diabetes?

No. Many people reverse or prevent progression by improving diet, activity levels and overall health (CDC, 2024; Mayo Clinic, 2023). 

Is prediabetes dangerous?

On its own, it’s not immediately harmful, but it increases the risk of serious health issues over time if left unmanaged (Mayo Clinic, 2023).

Can I check my blood sugar at home?

Yes. At-home tests like HbA1c kits provide a convenient way to monitor your levels without visiting a clinic.

How often should I test my A1C if I have prediabetes?

Every 1-2 years is typically recommended, but your healthcare provider can advise based on your individual situation (CDC, 2024).