Diabetes does not always announce itself with obvious symptoms.

For some people, blood sugar can remain elevated for a long time before they realize anything is wrong. Others may notice small changes - such as becoming unusually thirsty, waking up frequently to urinate, feeling exhausted, or experiencing blurry vision but assume these symptoms are caused by stress, aging, lack of sleep, or simply being busy.

That is one reason diabetes can sometimes go undiagnosed.

Recognizing possible warning signs does not mean you can diagnose diabetes from symptoms alone. Many of these symptoms have other possible causes. The only reliable way to determine whether someone has diabetes is through appropriate blood glucose testing and medical evaluation.

Still, knowing what to watch for can help you recognize when it may be time to talk with a healthcare professional.

Here are seven possible warning signs worth knowing.

What Is Diabetes?

Diabetes is a group of conditions in which blood glucose levels become too high.

Glucose is an important source of energy for the body. After eating, carbohydrates are broken down into glucose, which enters the bloodstream.

The hormone insulin, produced by the pancreas, helps glucose move from the bloodstream into cells where it can be used for energy.

In type 2 diabetes, the body may become less responsive to insulin, while the pancreas may eventually be unable to produce enough insulin to keep blood glucose within a healthy range.

Type 1 diabetes is different. It occurs when the immune system destroys the insulin-producing cells in the pancreas, resulting in little or no insulin production.

Gestational diabetes can develop during pregnancy.

Although these forms of diabetes have different causes and characteristics, they can all involve elevated blood glucose.

1. You're Urinating Much More Often Than Usual

One of the classic symptoms associated with high blood sugar is frequent urination, medically known as polyuria.

When glucose levels become sufficiently high, the kidneys may begin passing more glucose into the urine.

Glucose draws water with it, which can increase urine production.

As a result, someone may notice that they are:

• Going to the bathroom much more frequently

• Producing larger amounts of urine

• Waking up several times during the night to urinate

• Suddenly needing to urinate more often than before

Occasionally getting up once during the night is not necessarily a sign of diabetes.

Nighttime urination can have many causes, including drinking fluids late in the evening, certain medications, prostate problems, sleep disorders, pregnancy, and other medical conditions.

But a persistent and unexplained increase in urination, especially when accompanied by increased thirst, deserves attention.

2. You Feel Extremely Thirsty

Frequent urination can contribute to fluid loss.

As the body loses more water, the brain may signal that you need to drink more.

This can result in persistent thirst, sometimes accompanied by a noticeably dry mouth.

You might find yourself drinking far more water than usual without feeling satisfied.

Again, thirst by itself does not mean someone has diabetes.

Hot weather, exercise, dehydration, salty foods, fever, certain medications, and other conditions can also make you thirsty.

The combination is more important.

For example:

Increased thirst + frequent urination + unexplained fatigue

is a pattern worth discussing with a healthcare professional.

3. You're Constantly Hungry or Feel Hungry Soon After Eating

Another possible symptom is unusually strong or persistent hunger, sometimes called polyphagia.

This can occur because glucose may remain in the bloodstream rather than being effectively utilized by cells for energy.

The body may respond by signaling that it needs more fuel.

A person might notice:

• Feeling hungry shortly after meals

• Eating larger portions than usual

• Having frequent cravings for food

• Feeling unsatisfied after eating

But increased appetite has many possible explanations.

Changes in physical activity, sleep, stress, medications, hormonal conditions, and dietary patterns can all influence hunger.

Therefore, persistent increased appetite should be considered alongside other symptoms rather than treated as proof of diabetes.

4. Unexplained Weight Loss

Unexpected weight loss is another symptom that deserves attention.

If the body cannot effectively use glucose for energy because of insufficient insulin or impaired glucose utilization, it may begin using stored fat and muscle as alternative energy sources.

This can contribute to weight loss.

The change may be particularly noticeable when someone is losing weight without intentionally changing their diet or exercise routine.

For example, someone may notice that their clothes are becoming looser even though they haven't been trying to lose weight.

Unexplained weight loss has many potential causes, however, including thyroid disorders, gastrointestinal conditions, infections, cancer, depression, medication effects, and other health problems.

That is why unexplained weight loss should not simply be attributed to diabetes.

It deserves medical evaluation.

5. Persistent Fatigue or Unusual Lack of Energy

Feeling tired after a poor night's sleep is normal.

Feeling exhausted almost every day despite getting adequate rest is different.

Persistent fatigue can occur with diabetes because the body may not be using glucose efficiently for energy.

A person might describe the feeling as:

• Constant tiredness

• Low energy

• Difficulty concentrating

• Feeling physically drained

• Needing frequent naps

• Struggling with ordinary activities

But fatigue is one of the least specific symptoms in medicine.

Poor sleep, anemia, stress, depression, infections, nutritional deficiencies, thyroid disorders, medications, and many other conditions can cause similar symptoms.

If unexplained fatigue persists for weeks, it is worth discussing with a healthcare professional rather than assuming the cause.

6. Blurred Vision

Changes in blood glucose can affect the fluid balance in the eye and temporarily alter the shape of the lens, which can cause blurred vision.

Someone may notice that:

• Reading becomes more difficult

• Objects appear slightly out of focus

• Vision changes from day to day

• Glasses seem to work differently than usual

Blood glucose fluctuations can sometimes cause temporary changes in vision.

However, persistent or sudden vision changes should never automatically be blamed on diabetes.

Eye conditions can have many causes.

And sudden vision loss, a sudden curtain-like shadow, new flashes or numerous floaters, or other acute visual changes require urgent medical assessment.

Diabetes can also cause longer-term damage to the blood vessels of the retina, known as diabetic retinopathy.

That is one reason regular eye examinations are important for people with diabetes.

7. Slow-Healing Cuts or Recurrent Infections

Another possible warning sign is that minor cuts or wounds seem to take unusually long to heal.

Persistently elevated blood glucose can affect circulation and immune function, which may make it more difficult for the body to respond effectively to infections and injuries.

Some people with diabetes also experience recurrent infections, including certain skin infections, urinary tract infections, or genital yeast infections.

You might notice:

• Small cuts taking unusually long to heal

• Repeated skin infections

• Frequent fungal or yeast infections

• Persistent itching or irritation

• Recurrent urinary infections

These symptoms can have many other causes, so they are not diagnostic of diabetes.

However, recurrent or difficult-to-treat infections deserve medical attention.

Other Changes That Can Occur

The seven symptoms above are among the better-known warning signs, but diabetes can also affect other parts of the body.

Some people may experience:

Tingling or numbness