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Disease

Type 2 Diabetes

Learn about type 2 diabetes, including its symptoms, diagnosis, laboratory tests, treatment and prevention.

Last Reviewed 26 Jul 2026
Reading Time 9 min read

Overview

A routine blood test at a check-up, rather than any dramatic symptom, is how many people first learn they have type 2 diabetes. The condition can develop quietly over years, sometimes with barely noticeable signs, which is exactly why so many people are living with it without knowing.

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Key Fact

More than half of people living with diabetes worldwide were not taking any medication for it in 2022, most often because the condition had not yet been diagnosed, or was diagnosed too late. Type 2 diabetes is often preventable, and even once present, is one of the most manageable chronic conditions when caught early.

Warning

Sudden confusion, difficulty breathing, or unusually fast breathing are signs of a serious diabetes-related emergency and need immediate medical care. If you have risk factors for type 2 diabetes, such as excess weight or a family history, ask your doctor about screening even without symptoms.

AT A GLANCE

Disease Summary

Category Non-Communicable Disease
Cause A combination of insulin resistance and reduced insulin production by the pancreas, causing blood sugar levels to rise over time
Transmission Not applicable; type 2 diabetes is a non-communicable condition and cannot be spread between people
Body System Endocrine System
Preventable Yes
Curable No

Symptoms

Common Symptoms

Type 2 diabetes symptoms are often mild and can take years to be noticed.

Increased Thirst

Feeling unusually thirsty, even after drinking fluids, is a common early sign.

Frequent Urination

Needing to urinate more often than usual, including at night, often accompanies increased thirst.

Fatigue

Persistent tiredness, even after adequate rest, can occur as the body struggles to use blood sugar for energy.

Blurred Vision

High blood sugar can temporarily change the shape of the eye’s lens, affecting vision.

Unintentional Weight Loss

Losing weight without trying, despite normal or increased appetite, can be a sign of poorly controlled blood sugar.

Danger Signs

Seek emergency medical attention immediately if any of the following develop.

Confusion or Extreme Drowsiness

Can indicate dangerously high or low blood sugar and needs emergency care.

Rapid, Deep Breathing

Can occur during severe illness alongside very high blood sugar and needs urgent attention.

Signs of Severe Dehydration

Extreme thirst, dry mouth, and little or no urination can develop with very high blood sugar.

A Foot Wound That Is Not Healing or Looks Infected

Redness, swelling, or a wound that will not heal needs prompt medical attention to prevent serious complications.

Diagnosis

HbA1c Blood Test

Measures average blood sugar over the past two to three months and is the most commonly used test to diagnose diabetes.

Fasting Blood Glucose Test

Measures blood sugar after not eating or drinking anything except water for at least eight hours.

Oral Glucose Tolerance Test

Measures blood sugar before and two hours after drinking a sugary solution, sometimes used when other results are unclear.
Important
Because type 2 diabetes often causes mild or no symptoms for years, many people are only diagnosed through routine screening rather than because they felt unwell. Regular check-ups matter, particularly for people with known risk factors.

Laboratory Tests

HbA1c (Glycated Haemoglobin)

A result of 6.5 percent or higher on two separate tests generally confirms diabetes.

Sample Venous blood
Time 24–48 hours

Fasting Plasma Glucose

A result of 126 mg/dL (7.0 mmol/L) or higher generally confirms diabetes.

Sample Venous blood, after 8+ hours fasting
Time Same day

Oral Glucose Tolerance Test (OGTT)

A 2-hour result of 200 mg/dL (11.1 mmol/L) or higher generally confirms diabetes.

Sample Venous blood, before and 2 hours after a glucose drink
Time A few hours

Random Blood Glucose

A result of 200 mg/dL (11.1 mmol/L) or higher, together with symptoms, can support a diagnosis.

Sample Venous blood
Time Immediate

Laboratory Note

A diagnosis of diabetes is usually confirmed with two abnormal test results, either from the same sample or repeated on a different day, rather than from a single reading alone.

Treatment

Lifestyle Changes

Regular physical activity, a balanced diet, and maintaining a healthy weight are the foundation of managing type 2 diabetes, and can sometimes bring blood sugar into a normal range without medication.

Route Diet, physical activity, and weight management
Duration Ongoing, lifelong

Blood Sugar-Lowering Medication

Medications such as metformin are commonly used first, with other options or insulin added if needed to reach blood sugar targets.

Route Oral or Injectable
Duration Often long-term, adjusted over time

Treatment Note

With significant weight loss and lifestyle change, some people with type 2 diabetes achieve remission, meaning blood sugar stays in a normal range without medication. This is not the same as being cured, and regular monitoring still matters, since the underlying tendency toward high blood sugar can return.

Prevention

Maintain a healthy weight

Reaching and maintaining a healthy body weight significantly reduces the risk of developing type 2 diabetes.

Stay physically active

At least 150 minutes of moderate physical activity each week helps the body use insulin more effectively.

Eat a balanced diet

Limiting added sugar and saturated fat, and eating more whole foods, supports healthy blood sugar levels.

Avoid tobacco use

Smoking increases the risk of developing type 2 diabetes and its complications.

Prevention Note

Type 2 diabetes is often preventable, or can be significantly delayed, through these everyday lifestyle choices, even in people with a family history of the condition.

Risk Factors

Higher Risk

These factors increase the likelihood of developing type 2 diabetes.

  • Being overweight or living with obesity
  • A family history of diabetes
  • Age over 45, though it is increasingly diagnosed in younger people and children

Related Health Conditions

These conditions are linked to a higher risk of type 2 diabetes.

  • Prediabetes, where blood sugar is higher than normal but not yet in the diabetes range
  • A previous diagnosis of gestational diabetes
  • Polycystic ovary syndrome (PCOS)
  • High blood pressure or abnormal cholesterol levels

Lifestyle Factors

Everyday factors that increase risk over time.

  • Limited physical activity
  • A diet high in refined sugar and saturated fat
  • Tobacco use

Risk Note

Having one or more risk factors does not mean type 2 diabetes is inevitable. Many of these factors, particularly weight, activity levels, and diet, can be meaningfully changed.

Complications

Heart Attack and Stroke

Diabetes significantly increases the risk of cardiovascular disease, which remains one of its most serious long-term risks.

Kidney Damage

Long-term high blood sugar can damage the kidneys’ filtering system, sometimes leading to kidney failure.

Nerve and Eye Damage

Can cause numbness or pain in the feet and hands, and damage the blood vessels in the eyes, which can lead to vision loss.

Complication Note

Most of these complications develop gradually over years of high blood sugar, which is why consistent management and regular screening for early signs matter as much as the initial diagnosis.

When to Seek Medical Care

Confusion or Extreme Drowsiness

Needs emergency medical attention, since it can indicate dangerously high or low blood sugar.

A Foot Wound, Sore, or Infection

Should be assessed promptly, since diabetes can slow healing and increase infection risk.

Sudden Vision Changes

New or worsening vision problems should be evaluated by an eye care provider.

Blood Sugar Readings Persistently Outside Target Range

Should be discussed with a healthcare provider, even without obvious symptoms, so treatment can be adjusted.

Emergency Advice

Because type 2 diabetes is a long-term condition, regular check-ups and open communication with a healthcare provider matter as much as responding to acute symptoms.

Prognosis

Highly Manageable With Early Diagnosis

Blood sugar can often be well controlled through lifestyle changes and, when needed, medication, significantly reducing the risk of complications.

Remission Is Possible for Some

Significant weight loss and lifestyle change can bring blood sugar into a normal range without medication for some people, though ongoing monitoring still matters.

Complications Are Largely Preventable With Good Control

Consistent management substantially lowers the risk of heart, kidney, nerve, and eye complications over time.

Prognosis Note

More than half of people living with diabetes worldwide are not currently taking medication for it, often due to late or missed diagnosis. Regular screening, especially for people with known risk factors, is one of the most effective ways to improve long-term outcomes.

Differential Diagnosis

Type 1 Diabetes

Usually develops more suddenly, often in children or younger adults, and always requires insulin from diagnosis, unlike type 2 diabetes.

Gestational Diabetes

Develops during pregnancy and is diagnosed through routine prenatal screening rather than typical diabetes symptoms.

Stress-Related High Blood Sugar

Can occur temporarily during serious illness or injury and usually resolves once the underlying issue is treated, unlike the persistent pattern seen in diabetes.

Clinical Note

Blood tests, along with the pattern and timing of symptoms, help distinguish type 2 diabetes from these other causes of high blood sugar.

References

World Health Organization (WHO)

World Health Organization fact sheet on diabetes causes, symptoms, diagnosis, treatment, and global prevention efforts.

American Diabetes Association (ADA)

Clinical guidance on diabetes diagnostic tests and thresholds.

Centers for Disease Control and Prevention (CDC)

Guidance on the A1C test, its use in diagnosis, and diabetes management targets.

Frequently Asked Questions

Can type 2 diabetes be cured?
Type 2 diabetes is generally a lifelong condition, though some people achieve remission, meaning normal blood sugar without medication, through significant weight loss and lifestyle change. This requires ongoing monitoring rather than being considered a cure.
Is type 2 diabetes the same as type 1 diabetes?
No. Type 1 diabetes occurs when the pancreas produces little or no insulin and always requires insulin treatment. Type 2 diabetes, which makes up more than 95 percent of diabetes cases, involves the body not using insulin effectively, and can often be managed with lifestyle changes and, when needed, other medications.
Can type 2 diabetes be prevented?
Yes, in many cases. Maintaining a healthy weight, staying physically active, and eating a balanced diet significantly reduce the risk, even for people with a family history of diabetes.
How is type 2 diabetes diagnosed if I have no symptoms?
Through routine blood tests such as HbA1c or fasting blood glucose, which is why regular check-ups matter, particularly for people with risk factors like excess weight or a family history.