Thyroid UK
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Test results - advice on vitamin supplements please

I just got some blood results back for B12, D and serum folate and would appreciate any advice on how to improve my levels, particularly on folate which I don't really understand. Range is in brackets - it was the Blue Horizon test, in case that helps.

I currently take 4,000iu Vit D per day, but my level is still low so I'll crank that up. I don't supplement B12 and was expecting it to be low, but it seems fine. Folate is something I don't really understand but clearly seems to be an issue. I would appreciate any advice on how to tackle it.

I recently had a prolonged bout of gastritis following fibriod surgery before Xmas. I was prescribed high doses of Nexium and Ranitidine to deal with the stomach acid, which played havoc with my thyroid levels for a while. My T4 shot too high, with resulting palpitations and anxiety. Endo took me off T4 completely for a week and then reintroduced it at a lower level, which seems to be helping. Am currently taking 100mcg levothyroxine and 5 mcg liothyronine p.d. T4 and T3 are now back within normal(ish) tolerances, but my TSH is unusually high for me. It is generally below 0.5 and has been for over a year, so I'm wondering if this is a freak reading due to coming off T4 completely for a week about 3 weeks ago. I also wonder if the gastritis and acid meds may have caused a malabsorbtion issue?

Thanks for any and all suggestions!

Vitamin D - L43 (Deficient <25nmol/L. Insufficient 25 - 50. Consider reducing dose >175)

Vitamin B12 - 429 (Deficient <140pmol/L. Insufficient 140 - 250. Consider reducing dose >725)

Serum Folate - L5.80 (8.83 - 60.8nmol/L)

Ferritin - 41.1 (20 - 150ug/L)

TSH - H 5.59 (0.27 - 4.20mIU/L)

T4 Total 101.6 (64.5 - 142.0nmol/L)

Free T4 18.01 (12 - 22pmol/L)

Free T3 3.83 (3.1 - 6.8pmol/L)

6 Replies


You didn't say what your previous Vit D level was, and when?

4,000 iu is, generally, a maintenance dose. You need to first get to an optimal level and then take a maintenance dose which for many people might be 3,000 - 4,000 iu. But it depends on your height, build, weight, and your individual rate of absorption which is affected by many things.

Vit D is better absorbed when taken with something oily/fatty.

Here's my Vit D post with lots of info that I still add to - 🤓

It's best to have Vit B12 of over 500.

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3,000-4,000IU isn't a maintenance dose it's a dose for people with vitamin D levels in around 70 who want to raise it higher. A maintenance dose is around 1,000-2,000IU per day.

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I respectfully disagree with you.

I had already explained that as individuals we absorb at different rates. The main goal is to get to the optimal level and then to switch to a maintenance dose.


Hi - gastritis may well have affected your gut bacteria, as well as absorption problems caused by antacid.

Vit d - you need to up your dose - do you also take vit k2-mk7 and magnesium?

Folate - one of the b-vits. AT below range levels your GP should prescribe high dose (5g I think) folic acid tablets. If you can't get these, the best form to take is metylfolate.

B12 - whilst not desperately bad, this is less than optimum. It is usually recommended to raise this to around 1000. As this is water soluble any excess gets removed in urine so is not dangerous. Anaesthetics deplete this so it may well be lower than it was.

Ferritin - for thyroid this needs to be at least 70, ideal 100-130. You need iron tablets - ferrous fumerate or sulphate, 2 or 3 per day with 1000 vit c with each one to help absorption - 4 hrs away from levo/lio. Alternatively eat liver regularly.

Thyroid meds - you currently appear to be under-medicated as your TSH is hih and ft3 low, but you may not actually be as it could take another 2/3/4 weeks to show full effects of levo after you stopped it. Almost as if you were starting from scratch I would say. I would hold off and re-test then if you were previously ok on this dose.

Just another thought - after stomach and digestive issues, it mightn't do any harm to have a short course of probiotics to help re-build?

Good luck

Gillian xx

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Thanks for this. I take my vit D as drops in olive oil, combined with K2. I'll look into magnesium too.

I will speak to GP about folate and ferritin, and also look at a B12 supplement. I already take Optibac probiotics every day together with a fybogel sachet to keep IBS symptoms at bay.

My guess is that you're right about the thyroid levels. I don't think they're going to be a fair reflection yet and will re-test in a month.


If your GP is ill-informed like many be prepared to self supplement both folate and iron (ferritin).

If you do have to go down this route every time you finish a packet of iron tablets wait 5-7 days then test your ferritin level. Some people respond to iron supplementation faster than others and iron at too high a level is toxic.


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