Thyroid UK

How big a dose of Vitamin D is too big?

As I have mentioned in another post, I am currently in France for 3 months and recently had a blood test as I felt so rubbish. Turns out my Vitamin D is 14 (30 - 100) so well below what it should be. The Doctor I saw here said to take supplements and go to see my doctor on my return to the UK in September. I have just been to the chemist and she said that I should have been given a prescription. I explained that I am just visiting and will see my own doctor in a few weeks and she gave me an over the counter dose of ... 100,000 UI. It is a one off dose in an Ampoule and is taken orally. One thing it does say is not to take it if you are allergic to Vit D but how would I know?? Has anyone else had a dose this size??

5 Replies

My level is 12nmol and my Endo would normally prescribe a 300,000iu injection BUT I can't tolerate Vit D supplements even at a low 800iu dose. There are quite a few people on the forums that have a problem taking Vit D so to jump in with a high dose might not be the wisest thing to do if you don't know how you will react to it.

Plus if your Vit D is very low you should be having further tests such as calcium before supplementing as it's important to find out why you are deficient. If your calcium level is high then you would need a parathyroid test done.

Personally I would start on a low dose and see your GP when you get back. It can take up to 3 months for Vit D to improve especially for those of us that are very low.


Thanks for that - I think that, although it is apparently not uncommon to start treating at 300,000 UI (injection) I will look at taking a smaller dose to start with. Did you notice much difference once your level improved?


As the supps don't agree with me I don't take any on a regular basis, I maybe manage a few days a week, so I doubt my levels have improved at all, will find out next month.


Some info I posted the other day, worth reading it right through:


Hi - I had forgotten I had saved that information you told me about last time - thank you. It looks as though they give higher doses (300,000 injection) to treat but I am just concerned that I may react badly. I might break open the phial of liquid and just take a bit (the liquid is apparently 2.5mg of Cholecalciferol and meant to be taken in water).


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