Feeling Tired but Blood Tests Are Normal? Here’s What Might Be Missing

Why You Can Have “Normal” Blood Tests and Still Feel Tired

Many patients come to see us with the same concern:

“I’ve had blood tests, and everything is normal… but I still don’t feel right.”

This is more common than you might think—and in many cases, it reflects the difference between identifying disease and optimising health.

What Do “Normal” Blood Tests Actually Mean?

Standard blood tests are designed to detect established disease.

They are very good at identifying clear abnormalities—such as diabetes, anaemia, or significant thyroid dysfunction.

However, they are not always sensitive enough to detect early or subtle changes that can affect how you feel day to day.

In other words: “Normal” doesn’t always mean optimal.

The Role of Early Insulin Resistance

One of the most commonly missed contributors to fatigue and metabolic symptoms is early insulin resistance.

This can develop gradually over many years, often without obvious warning signs.

Importantly, it can be present even if:

• your weight is within a healthy range

• your glucose levels are normal

• your HbA1c is within the standard range

• 
  

At this stage, the body is beginning to struggle with how it processes energy—but it hasn’t yet reached the threshold for a formal diagnosis.

Subtle Symptoms to Be Aware Of

Early metabolic changes can present with symptoms that are easy to dismiss or attribute to a busy lifestyle.

These may include:

• persistent fatigue

• brain fog or difficulty concentrating

• increased hunger, particularly after meals

• gradual weight gain, especially around the abdomen

These symptoms are common and non-specific—but when they occur together, they can suggest an underlying metabolic imbalance.

Why These Changes Are Often Missed

In routine testing, we typically measure:

• glucose

• HbA1c

  
  

While important, these markers often remain normal until later in the process.

Earlier indicators—such as fasting insulin levels or subtle lipid pattern changes—are not always included in standard panels.

This means that early insulin resistance can go undetected for years.

Why Early Detection Matters

The encouraging news is that early metabolic changes are often highly responsive to simple interventions, including:

• improving sleep quality

• adjusting diet and meal timing

• increasing physical activity

• managing stress
  

The earlier these patterns are identified, the easier they are to address.

A More Personalised Approach

At Mews Medical, we take a more detailed and individualised approach to health assessment.

This may include looking beyond standard markers and interpreting results in the context of your symptoms, lifestyle, and long-term health goals.

The aim is not simply to rule out disease—but to help you feel and function at your best.

When Should You Consider Further Assessment?

If you have ongoing symptoms such as fatigue, brain fog, or unexplained changes in weight—despite being told your tests are normal—it may be worth exploring this further.

A more personalised assessment can often provide clarity, reassurance, and a clear plan going forward.

If this resonates, you can learn more about our health screening services or arrange a consultation with one of our GPs.

About the Author

Dr Laura Wood is a UK-trained GP with over 20 years’ experience, with a special interest in women’s health, metabolic health, and preventative medicine. She is co-founder of Mews Medical, a private GP practice in Kensington and Marylebone offering personalised, proactive healthcare.