Vitamin D side effects

I have been taking vitamin d since April I am on Fultium D2 800IU capsules just one a day. The last few days I feel really nauseous and got this horrible dizzy feeling more when I'm in bed and turn over and everything starts spinning, very weird. I am also on Levo 75mcg and had a blood test two weeks ago which have come back 'normal' no action required but at that time hadn't got the dizziness or nausea. Read the leaflet with the vit d and it does say it can cause nausea. anyone got any ideas?

24 Replies

If you think it is the vitamin D that is the problem did you have your vit D levels checked out before you started taking it? If not it might be an idea to have that done.

Yes Vit d was checked and found to be low so Doc prescribed it for me.

800IU's is a very LOW dose so doubt it's the D. Also I believe D3 is better for us. I think you would have had the dizziness earlier.

Could it be B12 ? If you are low then it can cause vertigo/dizziness like symptoms..... Do you know your level ?

Thank you Marz I don't know b12 levels I haven't been to the docs with the dizziness as yet trying to see if it all goes away. I'm living in hope!

Have just checked on-line and I see Fultium is D3 and not D2 - so that's good. I would request a test for B12 - Ferritin - Folate - Iron. Your Doc could possibly offer you a pill for the dizziness - treating the symptom without looking for the cause....

Scroll down for all the signs and symptoms of B12 Deficiency - it is very serious when it is LOW :-)

Thank you for your help its nice to know there are people out there that care xxx

Hi Marz !

I'm sure you'll recall supplementing with D3, or even sun exposure would not be recommended in those who exhibit a specific "vitamin D dysfunction" according to one body of opinion:

We simply don't know whether Silverlady5 has this ( - or not) . . . . . . but she does feel there to be an association btwn her stated symptoms and her "vit D" intake.

I know even 800IU ( = 20mcg) per day of "Vit D3" can contribute to feeling UNWELL IN those who have this dysfunction ( - or hypersensitivity) - this CAN be after several or many months of supplementation, b4 the blood calcidiol reaches a relative low figure ( - 'low' that is, for those NOT affected by this dysfunction).

Hope your climate remains warmer and sunnier (than ours) . . . . the UK has started feeling the cold and darker evenings now !

If you read another post of mine - you will see I do refer to the TH1 and TH2 issue. Do not have time to do it ALL every time. Always hope that if people are interested in what I have to say they will click onto my name and check my posts and replies. That is what I do and learn lots :-)

After your posts I did reduce my VitD from 10,000IU's and soon felt awful. I have returned to the aforementioned amount and now feel FINE :-)

Albeit I do have Hashimotos and Crohns but do need VitD too :-) Have always been an enigma !!

If you're an enigma, Marz . . . . I get the feeling you're one of those very nice ones ! < ;~)x

How interesting an experience you report - reducing from 10,000IUs (=250mcg) per day made you feel worse . . . . which improved once more on recommencing.

[In contrast, I couldn't manage a daily dose of 25mcg, have come off D3 all together and altho' the amounts from diet is v. low, am nonetheless reducing D containing foods . . . . . . . but interestingly, my calcidiol blood levels aren't falling as fast as the data ( - for the 'healthy'?) suggests they should: half life of 8-16 weeks or so ! Yeah, right ! Not for me, it seems ! ! !

[I wonder what your blood levels were at your lowest point and now, say ?]

The observation in your case would seem to suggest you don't have a Th1 inflammatory response ? Or at least not this darn "D dysfunction" ( - you may have elaborated on this already elsewhere !).

Let's not ( - any of us !) try to do it ALL ( - too wearing!) - I'm aware you do a great deal already, Marz . . . . . . and have appreciated those of your contributions I've read ( - as previously mentioned ?) !

My first test was here in Crete around 6 years ago - and I was DEFICIENT - latterly I was OPTIMAL after treatment ! So much for sunshine ! I swim loads so am exposed to the midday sun for 30 minutes daily for six months of the year ! Had been living here for 5 years before being tested.

I remain an enigma !!

Maybe you will come up with more information - so do let us all know :-)

One huge enigma here is the significant range of responses to "vit D" being found in people. All vital empirical observations, which will ( - in the end) be v. valuable to a host of researchers/academics in making sense of what's happening. Nobody REALLY understands this D field fully yet !

Your reply brings another significant point to light: that ample sunshine in some cases does not raise calcidiol blood levels to a particular desired value ( above 50nmol/L or 75 ?), . . . . but that value CAN be reached with copious daily doses ! V. noteworthy !

This CONTRASTS with blood levels not rising AT ALL with high supplementation over many months, which has also been observed ( - albeit in a limited number).

If I come across any info shedding light on your scenario, I'll be sure to bring that to your attention. However, if you are curious enough in the meantime, I'd suspect the best place to field this out to, would be a forum specifically for the "vit D" dysfunction ( - I've not spent time on any of those so far, but believe there is at least one such forum . . . . and there may be two ?).

Glad on this issue, at least Marz you've found what seems to work for you, in reducing symptoms. As larger dose D supplements have only come about since ~ 2010, 10 years ago getting 250mcg/day would have been much trickier !

The era of mass high dose supplement availability is really in its infancy, and is likely to see new insights and developments over the coming decades, clarifying the presently incomplete picture further. We watching and waiting !

Kind regards from an autumnal W Mids.

Sat 24/10/15

I'm not as knowledgeable about this as some people on the forum but I take Vit D3 after a private test came back "severely deficient" so I got my own (looked for a decent brand), mega dosed to start with for two or three weeks then lowered dose, re-tested and found to be optimally replete so now take a maintenance dose.

Firstly, I assume it is D3 you are taking and not D2?

Secondly, are you taking Vit K2 as well. This is needed as Vit D3 aids with calcium and Vit K2 directs the calcium to the bones rather than to the arteries and soft tissue -

Both are fat soluble, are you taking your Vit D with the fattiest meal of the day?

Do you think your nausea and dizzy feeling could possibly be a bug/virus you may have picked up or is it just when in bed? Or maybe vertigo - positional vertigo can happen in bed.

Thank you Seaside Suzy I was also wondering if the problem was vertigo. Had that years ago when I first went through the menopause. I also get the dizzy feeling when bending down. i usually take Vit d in the morning so that wouldn't be with the fattiest meal. I think it's d2 I'm taking and no I don't take Vit K.

Hi Make sure calcium is in range as D can put it up dangerously .


Taking 800iu once a day won't improve your Vitamin D levels, it's just a maintenance dose. People take 5 to 10 times that much to address a deficiency, then when their levels are healthy they take 800iu to keep them there.

I had this for a while and the key thing is that it happens when you turn over in bed, and the whole world tilts. I blamed the Hashi as we tend to do, but it turned out to be something about flakes in the inner ear, which just happens. There is a manoevre that a doc can do that clears it, and I found a video on what they do, and did it to myself and have not been dizzy since, which is nice as when I first got up I could not walk in a straight line.

When I get a mo, I will see if I can find a link (or remember what it is called), but worth a look. I think I did a search on "dizzy when lying down". Hope it works for you.

Yes, this is called BPPV (Benign Paroxysmal Positional Vertigo). I've had it too for some time and the Epley maneuver was the best thing to treat it. Silverlady5, since it happens when you turn in bed or bend down it may very well be your ear and you need to see an ENT.

Thank you this is very interesting I would be willing to try anything that would get rid of this fuzzy headed feeling and dizziness when I turn over in bed. I also have a sick feeling too did you have this too?

I had positional vertigo too and got the Eply treatment. It worked for me. I do know there was only one doctor in my surgery who performed it :)

I have never heard of the Eply treatment . What exactly is it?

Its nothing scary. You lay on the doctors bed and he places your head I'm different positions. It takes about 5/10 mins. You have to sleep sitting up for two nights and not lay on the affected side for a week.

It can come back so far so good for me. I have been clear of symptoms for a month


I could not take Fultium, like you felt very nauseous and all my skin tingled. I thought it might be dye allergy, as the Fultium is bright blue. Reported it to my Dr, who did not know what else to prescribe, so went to pharmacy and now take vitabiotics D3 with no side effects, although my calcium level is highish, endo says still to take 2000 iu daily, as my vitamin d level is still not high.

Hi it may be you have an inner ear infection or Labrynthitis. If the nausea and dizziness go if you sit still and keep your head still but return on movement then it could be your ears. Best check with a doctor.

Hi SL5,

I've read through the chain of posts on this thread - it may be your symptoms are not at all related to the "Vit D3" intake . . . . . in which case you have other avenues to pursue.

However, IF there is a connection ( - as you felt, in your case, at least initially!) it COULD be explained by a known and recognised "vitamin D dysfunction" ( - or "hypersensitivity") which to date REMAINS quite unfamiliar to Drs (and others !) for the present - in spite of having been well documented over the years.

For further info, see:

This dysfunction is NOT uncommon . . . . . . but I fear OFTEN REMAINS unidentified in many people. It features include a delayed effect of symptoms, typically months after the on-set of supplementation DEPENDING on factors such as the calcidiol level when supplementation was started and the doses taken.

Hope this helps !

Take care.

You may also like...