Energy, Fatigue and Tiredness Health Checks and Blood Tests

Low energy and persistent fatigue are among the most common reasons people seek medical advice. While tiredness is often related to lifestyle, it can also be associated with underlying health conditions, nutritional deficiencies, hormone imbalances, or metabolic disorders. Blood testing can help identify potential causes and guide the next steps.

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Vitamin D (25 OH) Blood Test

Do you often feel tired, rundown, or struggle with muscle aches and pains? You may have vitamin D deficiency, especially if you spend little time outdoors, have darker skin, or are over 65 — all factors that can affect your ability to produce vitamin D

  • Results estimated in 2 working days
  • 1 biomarkers
£39.00
Iron Blood Test

Feeling constantly tired or struggling with low energy? Your iron levels could be the reason

  • Results estimated in 3 working days
  • 5 biomarkers
£49.00
Vitamin B12 (Active) Blood Test

Are you experiencing symptoms of low vitamin B12, such as extreme tiredness, low energy, muscle weakness, or poor memory?

If your diet lacks B12-rich foods like meat, fish, or dairy, or you have a health condition that affects absorption—such as Crohn’s or coeliac disease, or pernicious...

  • Results estimated in 2 working days
  • 1 biomarkers
£39.00
Full Blood Count (FBC) Blood Test

A Full Blood Count (FBC) is a vital test for assessing overall health and detecting a range of conditions, including anaemia, infections, and immune disorders

  • Results estimated in 2 working days
  • 15 biomarkers
£59.00
Ferritin Blood Test

Are you at high risk of iron-deficiency anaemia, like increased blood loss or dietary deficiency, or do you have symptoms of iron overload, such as diabetes and liver disease? Our simple blood test measures your ferritin levels (a protein that stores iron in your body) to tell you whether your...

  • Results estimated in 2 working days
  • 1 biomarkers
£39.00
Lyme Disease (Borrelia burgdorferi) Antibodies (ELISA) Blood Test

Have you developed symptoms of Lyme disease after a tick bite or after spending time in a grassy or wooded area? If so, you should visit your GP as soon as possible and take photos of any rashes before they disappear

  • Results estimated in 4 working days
  • 2 biomarkers
£99.00
Advanced Tiredness and Fatigue Blood Test

Are you’re feeling constantly tired and fatigued without an obvious explanation? Perhaps you’ve been experiencing low energy levels for some time with no sign of improvement

  • Results estimated in 3 working days
  • 26 biomarkers
£119.00
Tiredness and Fatigue Blood Test

Feeling constantly drained, struggling with low energy, or experiencing brain fog? This test checks for common causes of fatigue, including iron deficiency, vitamin D deficiency, and thyroid conditions

  • Results estimated in 3 working days
  • 8 biomarkers
£79.00
Young woman with long dark hair is smiling and looking at the camera.
“There's a wide variety of causes for low energy and persistent tiredness. Our range of tests helps uncover potential contributors such as anaemia, nutrient deficiencies, hormone imbalances, and, less commonly, Lyme disease.”

Dr Tina Ghela, Head of Clinical, Medichecks

Which energy blood test should I choose?

The best test depends on your symptoms and how comprehensive you want your assessment to be.

What can cause low energy?

Feeling tired all the time doesn't always have a single cause. Fatigue can develop for many reasons, and several factors often contribute simultaneously.


Common causes include:

  • Iron deficiency or anaemia
  • Low vitamin B12, folate, or vitamin D
  • An underactive thyroid
  • Diabetes or poor blood glucose control
  • Liver or kidney disease
  • Hormone imbalances
  • Poor sleep, stress, or overtraining
  • Some medications


If you've been feeling persistently tired for several weeks or your symptoms are affecting your daily life, blood testing can help identify whether an underlying medical condition should be investigated.

FAQs

Can blood tests diagnose chronic fatigue syndrome?

Chronic fatigue syndrome (CFS/ME) is a clinical diagnosis based on your symptoms, medical history, and the exclusion of other conditions.


There isn't a single blood test that can diagnose CFS/ME. However, blood tests play an important role in ruling out other causes of persistent fatigue, many of which can produce similar symptoms.

Why am I always tired?

Persistent tiredness can have many causes, including poor sleep, stress, nutritional deficiencies, thyroid disorders, diabetes, hormone imbalances, anaemia, infections, and chronic medical conditions. Blood tests can help identify or rule out many of these possibilities.

What's the best blood test for fatigue?

Our Energy Essentials Blood Test focuses on some of the most common contributors to tiredness, while individual vitamin and thyroid tests can help if you're following up on a particular concern or monitoring an existing condition.

If you're looking for a broad assessment, the Optimal Health Blood Test is one of our most comprehensive tests, measuring a wide range of biomarkers associated with fatigue, including iron status, vitamin levels, thyroid function, inflammation, liver and kidney health, and blood glucose.

Can a vitamin deficiency make you tired?

Low levels of iron, vitamin B12, folate, and vitamin D are common causes of fatigue and reduced energy. Blood testing can confirm whether a deficiency is present.

Can thyroid problems cause tiredness?

Yes. An underactive thyroid (hypothyroidism) commonly causes fatigue, low energy, weight gain, dry skin, and feeling cold. A thyroid blood test can assess whether your thyroid may be contributing to your symptoms.

When should I have a blood test for fatigue?

If you've been feeling unusually tired for several weeks, your symptoms are persistent or worsening, or they're affecting your work or daily life, it's worth discussing your symptoms with a healthcare professional. Blood testing can often help identify common medical causes.

What if my blood test is normal, but I'm still tired?

Normal blood test results don't necessarily explain every cause of fatigue. Sleep disorders, mental health, chronic fatigue syndrome, medications, lifestyle factors, and other medical conditions may also contribute, so further assessment may sometimes be needed.