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Thyroid UK
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Vitamin D loading dose?

Serum vitamin B12 level 397 ng/l [ 197 - 771 ]

Serum folate level 4.8 ng/ml [ 2 - 18.7 ]

Serum ferritin level 81 ng/ml [ 13 - 150 ]

Serum total 25-hydroxy vitamin D level 39 nmol/L [levels should be >75 nmol/L at all times... Levels 25-50 indicate deficiency, supplementation is indicated...

Yesterday, GP prescribed loading dose of 3,200 IU of Fultium-D3, once daily for 12 weeks, then she'll reduce it to a maintenance dose. She said it is a fat-soluble vitamin and so is better taken with the fattiest meal of the day. She didn't know about the co-factors and asked me to repeat why they were important (to send calcium to bones instead of the arteries). She then said they don't usually prescribe anything else with it, and seemed relieved when I told her I've already purchased K2 MK7 and magnesium, she's happy for me to take them, I also informed her I've started supplementing B12, and why.

I also asked whether she prescribes levothyroxine by TSH or symptoms, she said by TSH 😢 I then asked whether she'll please consider prescribing by symptoms, seeing as TSH doesn't tell you how well the thyroid is working, it just tells you how hard the pituitary is kicking the thyroid...

I feel hopeful that she may be listening 😊

Anyway, my question: is the loading dose she prescribed enough, do you think, or should I just take the 5,000 IU vitamin D that I've already bought?

My current worst symptom is really REALLY painful legs, incidentally.

6 Replies


I would take the 5,000iu you've bought. My sister's GP prescribed 2 x 20,000 D3 per week when her vitD was 40. Take vitD 4 hours away from Levothyroxine.

B12 397 is probably okay but if you have symptoms of B12 deficiency in b12deficiency.info/signs-an... go to healthunlocked.com/pasoc for advice.

Folate is low in range so you might want to supplement 400mcg folic acid for a few months or supplement a B Complex vitamin.

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Thank you, Clutter

I do have a fair number of B12 deficiency symptoms.

I've started taking Thorne Basic B Complex , which contains 400 mcg Folate. Oh, flip, just noticed it contains Biotin, which can skew some blood test results 😢



Just stop taking the Biotin a couple of days before any blood test and it will be fine.

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Thank you 😊


To be honest, you were very lucky to get anything on prescription for Vit D. She's actually given you the virtual full loading dose over 12 weeks that you'd get if you were Deficient under 30 or 25.

Some people, including me, need a maintenance dose of 2000iu daily when their levels are optimal.

As your level is 39, and you need to get it up to 100-150, if it was me I would take the 5000iu daily at the moment.

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Thank you, SeasideSusie, I agree that I appear to be lucky so far with my GP 👍🏼😊 I didn't think she'd prescribe owt for Vit D, which is why I bought my own.

I'll use mine and keep hers for in case I need it later😊

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