Why is my ferritin 'normal' but I still feel exhausted?
Photo by Abbie Bernet on Unsplash
I'm working with a client at the moment (we're only a few weeks in, so this is very much a work in progress) whose ferritin came back at 11 µg/L. Her GP looked at that number, told her it was within range, and sent her on her way. No iron tablets or a follow-up plan. Just "It's fine".
Except she isn't fine. She'd been feeling tired for around three months. She gets headaches, feels short of breath sometimes, and experiences heart palpitations. She's been struggling to lose weight too but not getting very far.
Does this sound at all familiar?
If you've been told your ferritin is normal, but you still feel like a shadow of yourself, you are not imagining it, and you are not alone. So, let's talk about what's actually going on, because 'normal' on an NHS blood test and 'optimal' for how you actually feel are two very different things.
What does 'normal' actually mean on a GP blood test?
The NHS reference range for serum ferritin is roughly 24 to 340 µg/L for men and 11 to 310 µg/L for women. That range is built to catch disease, not to define what feels good in your body. It's basically the line between 'not currently ill' and 'everything else'.
So, if your ferritin result comes back at 12, or 15, or even 20, that's inside the normal range. Technically, not a problem. But technically, inside the range and optimal for you to feel well are not the same thing.
As a nutritional therapist, I tend to work towards a ferritin level of around 70 to 90 µg/L for both men and women. That's the level where most people actually start to feel like themselves energy-wise. Which means someone can be told their result is 'normal' while sitting at a fraction of what their body genuinely needs to function well. That gap is enormous, and it's exactly why a lot of ongoing fatigue goes unexplained.
Why ferritin drops in the first place
Ferritin is basically your iron storage tank. It's not the iron doing the active work in your blood; it's the reserve tucked away for when you need it. And there are quite a few reasons that tank can run low:
Not getting enough iron through your diet
Poor absorption of the iron you do eat
Increased need for iron, such as during pregnancy or growth spurts
Blood loss, through heavy periods, or through the gut (ulcers, certain medications, parasites)
Your body simply using iron up faster than usual
For my client, her picture is like a ball of wool that needs untangling. She's had heavy periods for the past year, which alone could explain a lot of iron loss. Her diet is genuinely low in iron-rich foods. She also has some ongoing digestive issues, which could be affecting how well she absorbs what she does eat, although her inflammation marker (CRP) came back low, so that's not a straightforward answer either. It rarely is.
It's never just about ferritin
This is the bit that gets missed constantly, and it's the bit I want to bang the drum about. Ferritin on its own tells you almost nothing. You need the full blood picture around it.
For someone with unexplained fatigue, I want to see as much of the jigsaw as possible, including:
A full blood count (haemoglobin, red blood cells, and the various markers that describe them)
A complete iron panel, not just ferritin on its own
B12 and folate
Thyroid function, properly checked (not just TSH)
Liver function
Vitamin D
Blood sugar markers
Inflammation markers
Why does this matter so much? Because low iron rarely travels alone. Take vitamin A, for example. Most people have never heard of the connection, but vitamin A is what helps move iron out of storage and into your developing red blood cells. If you're short on vitamin A, you could be eating iron-rich foods until the cows come home and your body still wouldn't be able to put that iron to proper use. It's a bit like having a warehouse full of stock with nobody to drive the delivery van.
The same goes for B12, folate, B6 and copper. Symptoms overlap. Deficiencies overlap. And your thyroid can produce almost identical fatigue, brain fog and weight struggles all on its own. Look at just one marker and you risk chasing the wrong thing entirely, or missing half the story.
So what should you actually do if your ferritin level is 'normal'?
If you've had a 'normal' result, but you still don't feel like yourself, here's where I'd start:
Ask for the full panel, not just ferritin. A single number rarely tells the whole story. If your GP is only testing ferritin, it's worth asking what else could be checked, particularly thyroid function, B12, folate and blood sugar.
Look at your diet honestly. Are you actually getting iron-rich foods in regularly? Red meat, dark leafy greens, pulses. And are you pairing the plant-based sources with vitamin C, which helps your body absorb iron properly? A glass of orange juice alongside your lentil soup will help.
Don't just crack on and hope it settles. If it's been going on for weeks or months, that's your body telling you something, not being dramatic.
Get someone to actually join the dots for you. Having more numbers on a page is only useful if someone looks at them alongside your diet, your digestion, your lifestyle, all of it together. That's the difference between a list of results and an explanation. This is genuinely the bit that makes the difference between guessing and actually knowing what's going on.
You don't have to just put up with feeling tired
If you've been told your results are normal and you still feel exhausted, that gap between what the test says and what you feel is real, and it deserves proper investigation.
I help people investigate this kind of picture by looking at the whole picture - what they eat, how they're digesting their food, the missing nutrients, their sleep, their stress levels - the bits that don't show up if you only look at one number.
If you've felt dismissed with a 'normal' result and you're still waiting to feel like yourself again, I'd love to have a proper look with you.