What Blood Tests Should I Take for Constant Fatigue?
Feeling tired occasionally is normal.
Feeling exhausted most days is not.
Fatigue is one of the most common reasons people seek blood testing — and for good reason.
It’s often linked to nutritional deficiencies that can be identified and corrected.
But the key question is:
Which test should you take?
The Most Common Nutrient Causes of Fatigue
While fatigue can have many causes, several nutritional deficiencies are frequently involved:
1. Iron Deficiency
Low iron can reduce oxygen delivery throughout the body.
Symptoms may include:
- Persistent tiredness
- Shortness of breath
- Dizziness
- Pale skin
- Cold hands and feet
Iron deficiency is particularly common in:
- Women with heavy periods
- Vegetarians and vegans
- Endurance athletes
Consider the Anaemia Profile if iron is suspected.
2. Vitamin B12 Deficiency
B12 plays a key role in energy production and nerve function.
Symptoms can include:
- Brain fog
- Low energy
- Tingling sensations
- Memory difficulties
Vegetarians and vegans are at higher risk.
3. Low Vitamin D
Vitamin D deficiency is extremely common in the UK, especially in winter months.
Low levels have been associated with:
- Fatigue
- Low mood
- Muscle weakness
4. Folate Deficiency
Folate works closely with B12 and iron in supporting energy and blood health.
Which Test Is Right for You?
The right test depends on your symptoms and context.
If You Suspect Iron or Anaemia
If you experience:
- Heavy periods
- Dizziness
- Breathlessness
- Extreme tiredness
The Anaemia Profile provides focused testing of iron stores and related markers.
If You’re Unsure What’s Causing Fatigue
When the cause isn’t obvious, a broader test makes more sense.
The NutriCheck Vitality & Vitamins Test assesses key vitamins and minerals commonly linked to fatigue.
This gives a wider overview rather than focusing on one nutrient alone.
View NutriCheck Vitality & Vitamins
If You Train Regularly
Fatigue in athletes and gym users can be linked to:
- Recovery stress
- Nutritional depletion
- Inflammation
- Micronutrient imbalance
The Competitive Athlete Blood Test provides a more comprehensive performance-focused assessment.
Explore the Competitive Athlete Blood Test
What If My Blood Tests Come Back Normal?
That’s valuable information too.
It rules out common nutritional causes and allows you to explore other explanations with your GP or healthcare provider.
Testing is about clarity — not assumptions.
How Often Should You Test for Fatigue?
If you’re:
- Starting supplementation → retest in 8–12 weeks
- Managing a known deficiency → follow professional guidance
- Training intensely → periodic monitoring can be helpful
Don’t Accept Constant Fatigue as “Normal”
Many people normalise feeling exhausted.
But fatigue is often a signal.
The right blood test can identify:
- Deficiencies
- Imbalances
- Areas needing attention
And once identified, these can often be addressed effectively.
Next Steps
If you’re unsure which test is right for you:
Take the Youth Revisited Quiz
Explore Vitamin & Nutrition Testing
Clarity leads to better decisions.
And better decisions lead to better outcomes.