Taking a week's dose of Vitamins in one go? - Thyroid UK

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Taking a week's dose of Vitamins in one go?

Helena877 profile image

A while ago when I went to see a Naturopath I told her all the vits I was taken (B12, B-complex, D3, K2MK4, Mag, Selenium, Zinc, Ferrous Fumerate + Vit C) and the difficulties in timing. She suggested taking some of these vitamins all in one go i.e. a week's supply of D3.

Could you do this? If you did it with say D3 would you have to take their counterparts of Magnesium and the K2 all in bulk too?

I just cannot make it work now I am on T3-only. Not enough hours in the day and trying to fit in a full-on detox with capsules, clay, probiotics, enemas etc. It's driving me nuts 🤣

12 Replies

I wouldn't suggest doing it for most nutrients. Too much iron in one go is likely to make you very sick and would give you severe stomach and gut pain. Too much vitamin C all in one go would give you diarrhoea from hell. Too much magnesium all in one go will also give you dreadful diarrhoea. (Various high-dose magnesium compounds are used by doctors to clear out patients' guts before colonoscopy.)

I have no idea what would happen if people took lots of zinc, selenium, B vitamins or vitamin K2 all in one go.


I personally would not take this naturopaths 'advice'.

Is this person registered with a Regulatory Body and professional standards department?

She's registered and works out of a professional outfit.

She offered good advice for some things, but I made decisions not to follow other recommendations.

It really was just D3 that she specifically mentioned taking in a week's doseage.

Stourie profile image
Stourie in reply to Helena877

If I remember correctly vitamin d should be taken daily Check with Vitamin D Deficiency UK just to make sure. I take all of my vits together at lunch time. Vit D3, K2, Magnesium and a B complex and pro biotic.

Jo xx

helvella profile image

As I understand, B12 absorption is a complex subject.

If you are on the appropriate dose of oral B12, then taking seven times as much is unlikely to increase your absorption substantially from that single dose. Over a week, it would considerably reduce the total amount absorbed simply because on six days a week there is none to be absorbed.

Further, I think that B12 absorption is maximised by taking the dose away from anything else - so you get a nicely concentrated dose going through your gut.

The only vitamin you can take weekly is vitamin D3 but even then there are arguments whether you should do so. One argument against it is that in nature you would get a daily dose of UVB rays from the sun to make vitamin D so should try and mimic that as much as possible. There have been studies done to back up both views but one problem with vitamin D studies is they tend not to supplement the patients with enough vitamin D or combine vitamin D with calcium. The only agreement I've seen is that monthly mega doses are bad.

The rest of the vitamins and minerals you mentioned are all available from food sources, and no way would anyone be eating a weeks supply of say vitamin B12, iron or zinc in one go.

Apart from issues with diarohea and nausea it should be pointed out water soluble vitamins e.g. B vitamins, vitamin C have short half lives so don't stay in your body a long time this is one reason you can take each of your iron tablets with vitamin C and not overdose on vitamin C. This means if you take a large dose one day a week the next 6 days you would be receiving none.

The only reason a naturopath would be saying take them in one go is because they either don't believe supplementing vitamins and minerals works or they don't think supplementing is needed. As there are dietitians and nutritionists who think that I'm not surprised a naturopath would think that. I personally would find a new one who understands that even with a good diet some people need to supplement.

helvella profile image
helvellaAdministrator in reply to bluebug

Not actually disagreeing at all, but if you consider the vitamin D production in a British summer, all too often you might get your whole dose in one day and none for the next six! :-)

It is because of this considerable variability of exposure to sun that weekly dosing seems possibly sensible - but I'd still agree with daily dosing by preference.

No point with most water soluable vitamins as you'd just lose the benefit. Some studies have suggested that although it's quite usual to dose D3 once a week, it actually works better in smaller doses more often (but I can't remember the name of the study). B12 you could take in big doses less often as long a you can store it. Minerals and vit C, no. I don't really see the advantage un;ess the tablets contain lots of nasty fillers and you'd be taking a single tablet with (overall) fewer fillers, in which case you might be better looking for different brands (It's much easier to stick to a daily routine)

helvella profile image
helvellaAdministrator in reply to Angel_of_the_North

If your body can absorb and store B12 quite well, you might absorb 10 micrograms from a dose (however large that dose is - there is a maximum feasible absorption). Which just about represents three days or so.

(The Pernicious Anaemia Society people are much hotter on the details than I.)

So you'd need it at least twice a week.

That's a good point.

If you take your supplements daily then it's harder to forget to take them.

However if you start doing every few days or weekly then you forget.

God no please don't do that, at the very best you will just absorb a certain amount (far less than you'd want) and excrete (get rid of) the rest, so you'd have wasted vitamins and money. At worst it can be very dangerous. Please please don't do this.

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