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Thyroid UK
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Falling B12 and Ferritin

Hi all,

Quick question:

I've been ill for over 9 years now without a diagnosis. Doctors are lost and can't figure out what is wrong with me. I've always believed it to be a thyroid or adrenal problem based on my symptoms but sadly my blood tests won't back that up. Recently however there's been a change in some of these tests, and I was hoping to get some thoughts from people more in the know than me on here about what these changes could possibly indicate, if anything.

Back in 2009 my B12 was 756 ng/L (range 180-900) and my Ferritin was 279.3 microg/L (range 20-300). These both seemed like good figures so I didn't worry about them. But in 2012 my B12 was tested again and it had dropped to 513 ng/L. Still nicely in the range but also a fairly substantial fall. Then about 6 months ago I had them both tested again and the B12 was 252 ng/L and the Ferritin 34.9! That's over 500 fall for the B12 and about 250 fall for the Ferritin. They're both now getting pretty close to the bottom of the range. These seem like very significant drops, even more so if what I've read about hypothyroidism causing low B12 and Ferritin is true. (Oh, and my haemoglobin is 15.4 (range 13 - 18))

I do have some symptoms that point to hypothyroidism:

Low temperature all the time (35.8 - 36.5)

Hair loss from head, under arm, pubic and legs

Low blood pressure

Digestive problems - bloating/gas/wind/constipation etc.

Increasing allergies

Fatigue and weakness

But then other symptoms that seem contrary to hypo that I have are - weight loss, no brain fog whatsoever, no pain at all, brisk reflexes, very greasy hair and a very healthy libido.

So it's all a bit of a muddle.

Also my most recent thyroid blood tests were fine (I think!):

TSH - 1.13 mU/L (0.3 - 5.5)

FT4 - 17 pmol/L (10.5 - 20)

FT3 - 4.8 pmol/L (3.5 - 6.5)

Parathyroid - 2.8 pmol/L (1.6-6.9)

Thyroid Peroxidase Abs - 2 IU/ml (0-50)

TSH Receptor Abs - less than 0.4 (0-0.4)

So I'm wondering if this drop in the B12 and Ferritin could be a sign of a developing or progressing thyroid issue? What I don't understand though is if this is a sign of thyroid problems why would it have taken 5 or so years before​ showing up? And why would those first years of being ill the B12 and Ferritin be perfectly fine? If anything I felt worse back then with the levels higher.

Also, should I be making an effort to get them back up? Like I said, I don't feel any worse for them falling, but obviously don't want them to get any lower.

Any thoughts on all of this highly appreciated!


9 Replies

People who have hypothyroidism will usually? often? develop low stomach acid as well. As a result they don't absorb nutrients from their food very well and over time they can become very low or deficient.

Another cause of this problem is being put on acid-suppressing medication. Indigestion is usually caused by low stomach acid, not high. By taking meds to suppress acid the problem is made worse and will rarely improve.

(If indigestion pain is caused by a stomach ulcer then there is a place for acid-suppressing meds while the ulcer heals, but they should never be prescribed long-term.)

The best solution to low stomach acid is to ADD acid to the gut, not suppress it. For more info on this, do a search for

Chris Kresser and GERD


scdlifestyle and (GERD or betaine or pepsin or apple cider vinegar or bitters)

GERD = Gastro-esophogeal reflux disease.

In the UK it is GORD = Gastro-oesophageal reflux disease. Most articles use GERD.


Having said all the above...

Yes, you need to supplement to get your nutrients to optimal levels and to keep them there. You should also concentrate on getting your gut health as good as you can get it.

And yes, you look like you are well on the way to developing hypothyroidism. Your Free T3 is in the lower half of the range, and this could be causing your symptoms. You might need it to be in the top third or quarter of the range to feel well, and it might have been too low for you for years. Your symptoms could have been made worse if you are suffering from autoimmune hypothyroidism. You don't have a test result for TgAb which is another type of thyroid antibody which also causes autoimmune hypothyroidism :



That's great, thanks! I'll do a search for the GERD stuff.

Would low stomach acid reduce appetite? As I feel like I've got a reduced sense of hunger, or I don't get the normal messages for hunger. Also my mum has GERD and I always thought that was too much acid? She has some pretty strong symptoms when she eats certain foods (chocolate, tomato, tea, coffee etc) but I don't have anything like her. I could definitely believe I had low acid though.

Oh, and I was told by docs that the TgAb was only necessary if you had cancer. I'm guessing that's not the case then?

Thanks again, really appreciate you taking the time to reply!


Lots of people on this forum have positive TgAb, and I'm sure they don't all have thyroid cancer.

Whether they have an increased risk for thyroid cancer I don't know, I am not knowledgeable on thyroid cancer.

But as far as I'm aware (don't trust me on this, do some checking of your own), the first conclusion you should reach with positive TgAb is that you probably have autoimmune thyroid disease. Coming to the conclusion that it means you have thyroid cancer is not justified without other signs and symptoms or testing.






with low stomach acid common as you age and you don't digest your food properly thus not getting your vitamins from food thus constipation.....you can take digestive enzymes be4 meals, or take braggs apple cidar vinegar 2 tbsp. with a little water and drink with a straw 30 min b4 meals, to help the digestive process, take a probiotic pill b4 bed every night and take supplements . Taking magnesium at night b4 bed helps with constipation and eating more fiber.....

this can also lead to hair loss and I don't know your age but if you are above 40 you could be going through hormone changes that also cause hair loss and adrenal fatigue causes hair loss from high cortisol.....make sure you are getting 8 hrs sleep a night, and stay calm not sweating the small stuff I life and taking things one day at a time...stress terrible on the hair, and low iron is also.


I'm actually a 29 year old man so unlikely to be hormonal changes!

I'll look to get some magnesium supplements and try the vinegar as well, thanks!


Two tablespoons of vinegar will almost certainly be way too much to start with. Instead you should try 1/2 a teaspoon in a small glass of water and drink it through a straw before meals or sip it throughout a meal. Increase by 1/2 teaspoon once you've adjusted to your current dose.

Anyone who swallows vinegar for any reason should be aware that it is not good for teeth. Use a straw, and after you've finished you should rinse, gargle and spit a few times with plain water to get rid of the vinegar. Cleaning the teeth is not a good idea because vinegar plus tooth brushing might strip the enamel off your teeth.

1 like

I had your problem and dr told me to either take digestive enzyme pills available from many places u take before every meal or to do the braggs apple cidar vinegar but it had to be braggs hence you can google that to see what kind that is and the properties it has....and I actually mix with a little water and lemon juice and drink with a straw bec it goes down easier ( and you may be shocked the first time you do it....i was...I chased it with some ice tea )but not convenient on the go so that is where digestive enzyme capsules comes in handy....


I would look up the symptoms of Coeliac on the Coeliac Uk website. Unexplained Low iron/ferritin and low vitamins are classic symptoms. Not every Coeliac has bowel problems. Bloating is a sign. Low ferritin will make you tired and could explain the hair loss. Did they test D3? I suspect that is possibly low too


I've had the Coeliac blood test which came back negative. Should I have much faith in that? When I'd looked at the symptoms before it didn't sound much like me but I'll take another look.

And yes, the D3 was low too. I'm currently taking supplements to sort it out.


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