Why You Are Always Tired and What Your Blood Test Results Actually Mean
We have all been there. You feel exhausted, you drag yourself out of bed, and you rely on caffeine to function. You finally see a doctor, get a blood test, and the text message comes back saying "Normal."
But you do not feel normal. You feel drained.
This disconnect between "statistically normal" and "optimally healthy" is one of the biggest frustrations in modern healthcare. In the UK, reference ranges for blood tests are often based on averages of the general population—which includes a lot of unhealthy people. Being at the very bottom of the "normal" range might mean you aren't technically dying, but it doesn't mean you are thriving.
Here is what might actually be going on with your fatigue and what specific markers you need to look at more closely.
The "Normal" Trap
Ferritin (Iron Storage)
The standard NHS range for Ferritin can be quite broad (often 15–300 ug/L). However, many people, especially women, experience hair shedding, brain fog, and fatigue when their levels drop below 50, even if the lab report says "normal" at 20.
The Optimisation View: We often aim for levels above 70-80 for optimal energy and hair growth.
Vitamin D
In the UK, almost everyone is deficient during winter. A result of 50 nmol/L is often considered "adequate" to prevent rickets (soft bones). But to support a robust immune system and high energy levels, many functional medicine experts suggest levels closer to 100-125 nmol/L.
The Optimisation View: If you are sitting at 55 and feeling tired, you might need a high-dose prescription supplement, not just a supermarket multivitamin.
Thyroid Function (TSH)
This is the master control for your metabolism. The reference range for TSH (Thyroid Stimulating Hormone) is typically 0.5 to 4.5 mU/L. If you are at 4.2, you are "normal." But many patients start feeling sluggish, cold, and foggy once they creep above 2.5.
The Optimisation View: A comprehensive check shouldn't just look at TSH. It should look at T4 and T3 (the active hormones) to see if your body is actually using the hormone effectively.
Vitamin B12 and Folate
B12 is crucial for nerve function and energy production. The "grey zone" here is huge. You can test within the normal range but still have functional deficiency symptoms like tingling hands or memory lapses.
If you are vegan, vegetarian, or have gut issues, you might not be absorbing B12 from food. Tablets might not be enough.
Discuss your symptoms with a doctor who listens
Viral Hangovers
Sometimes fatigue isn't a deficiency. It is a legacy. Post-viral fatigue (common after Glandular Fever, Flu, or Covid) can linger for months. Standard blood tests won't show this inflammation, leaving patients feeling like it is "all in their head." It isn't. It requires a managed recovery plan, not just "rest."
Moving from Normal to Optimal
If you are tired of being told you are fine when you know you aren't, it might be time for a different approach.
You need a doctor who looks at you, not just the numbers. A 20-minute consultation allows us to go through your lifestyle, your diet, and your specific symptoms to interpret those results in context.
Maybe you need an iron infusion. Maybe you need B12 injections. Or maybe you need a lifestyle adjustment plan. But you definitely need more than a text message saying "Normal."
