Vitamin D. Dose?

Had a blood test to test for thyroid issues. Came back clear, but that I have vitamin D insufficiency.

Was advise to take 20-50mcg(800-2000iu) of vitamin D per day for twelve weeks. Then get retested. When levels reach normal then to reduce this to 10mcg(400iu) per day.

After advice on this forum, I bought doctor's best vitamin D 50ug, softgels. Can't quite work out how 20-50mcg etc is translated into 50ug? How many tablets would that be? The suggestion on the container is one tablet per day?

35 Replies

ug (usually with an extending line down off the front of the u) is just another way of writing mcg. We dont have the special u on our keyboards by default so write mcg instead.

Okay. Thanks for the update..

My dr is prescribing Vit D3 ..I think because of Osteoporosis as she said my Vitamins regarding Hypo were OK but she did not say anything about retesting or reducing..think I read something about a urine test can confirm if there is too much Vit D in the urine..should I be asking her if and when I should have a urine test?


Hather, put up a new post as you are asking a question within a post (question) and you will get more responses with your individual question.

Also, if you have your results of blood tests for vitamins and/or thyroid hormones with the ranges include these too as 'ok' doesn't always mean optimal.

Thank you Shaws, my dr doesn't want to increase my Levo now up,to 50 cgm..TSH now 1.78 and T4

15.9 which is slight I,provement because of my age, nearly 82.?? The reason I asked her if,I,could,increase it was because I am getting an outbreak of,itchy forehead and Sandy dry scalp, which had cleared,up last,October,when Hypo,was,discovered and even the 25 com seem to help clearing it,up..and now in June it's. Breaking ouT again..the only new medicine I have been on in the last few weeks is the D3 and Vit she said it might affect the heart..but I don't have,heart problems and can well up,hills without getting out,of,breath but I do have deep short sleeps in the afternoon/evening and mostly sleep well at,night luckily. So I don't know if I should ask again..I never know if it's the surgery just cutting down cos of the cost.. tho I get on with my surgery fine

This was a private blood test and I know, from previous experience, that the doctors at my GP surgery aren't that interested in my health problems and do distort information to fit in with NHS guidance regarding cutting of resources, so thought I'd get an independent opinion.

But you are right. I will contact the company who did the tests next week and see if they can assist me. Or maybe the pharmacists. It's just that, my experience tells me they might necessarily give me an accurate reflection of these vitamins etc. So sorry to have had to trouble you on this matter..


What was your vitD result?

Think it was 37 in an earlier post - so dose needs to be more methinks 😊

Lydia, the Doctor's Best (and most) D3 supplements come in IU doses not mcg. Presumably you bought the 2000IU dose ones as you're saying you bought 50mcg.

2000IU is more likely to be a winter maintenance dose, it's not really enough to raise your level from 37.07nmol/L to the recommended level of 100-150nmol/L. This was explained in your previous thread.

If you want to see how much to use to raise your level, then check out the tables on the Vit D Council's website. Their unit of measurement is Ng/ml and we have to divide nmol/L by 2.5 to get Ng/ml. Your level in ng/ml is 14.8 so scroll down to the second table where it says

"My level is between 10-20 ng/ml"

You will see that to achieve the recommended level of 40-60ng/ml (100-150nmol/L) :

40 ng/ml you need 3200 IU D3

50 ng/ml you need 4900 IU D3

60 ng/ml you need 7000 IU D3

So the original suggestion in your previous thread of taking 5000IU is just about right. Not sure why you are only taking 2000iu???

I take 5000iu every other day have done for the last year, Drs Best

Apologies for asking a similar question to the last thread, but you informed me that you thought I had thyroid issues, which I don't have, so the information you gave me about tablets etc was directed at those who do have thyroid issues, so I assumed those vitamins etc and dosages are only for those with that condition, and not for someone who isn't? Or are all those supplements you mentioned in the other thread essential for me to take too to bring my levels all up to optimal levels regardless of not having thyroid issues??

Us Hypos need optimal levels of vitamins and minerals, it's part and parcel of doing as much as possible to help ourselves. However, there are recommended levels for general health.

B12 below 500 can cause neurological problems, that is possible for people in general not just Hypos. In Japan, the bottom of their reference range is 500.

Some interesting reading


Vit D is recommended to be 100-150\nmol/L (40-60ng/ml) which you can see on the Vit D Council's website

where if you scroll down to the tables you will see

"My level is between 40-50 ng/ml

According to most standards, including the Vitamin D Council, Endocrine Society and Institute of Medicine, you are getting enough vitamin D!

My level is between 50-60 ng/ml

You’re getting the right amount of vitamin D by the standards set by the Vitamin D Council and Endocrine Society. The Institute of Medicine, however, doesn’t feel there is enough evidence to say that having a level higher than 50 ng/ml is of any benefit."

40-60ng/ml = 100-150nmol/L

Grassroots Health has a Disease Incidence Prevention Chart on their website which is very interesting

So you can see that your 37.07nmol/L falls way below the recommended level according to both the Vit D Council and Grassroots Health. Both Bluebug and I suggested the dose needed to bring your level up in your last thread.


Ferritin needs to be 70 for thyroid hormone to work, that is our own thyroid hormone or replacement. That is the level where conversion of T4 to T3 takes place. As explained in your other post, although your TSH and FT4 are in range and good, your FT3 is in range but your conversion isn't particularly good.

Thanks again for all these relevant details. I shall take a look at those links and heed your words. Do I need magnesium or selenium tablets as was suggested?

If you take D3 you need the important cofactors, I linked to the Vit D Council's article on that in your other thread.

K2-MK7, Magnesium, and check the other cofactors too.

Selenium helps with T4 to T3 conversion and your conversion isn't particularly good, as explained in your other thread.

Is it permissible to crunch some of the larger tablets? Am having difficulties swallowing them and am concerned I might choke on them...

Lydia, I have tried D3 in liquid form. I am trying this one currently


Hi Lydia, over the years here we notice that the NHS is in dire need of updating when it comes to thyroid health. This includes vitamin D. I've posted Dr. Bergman's videos who thoroughly explains the reasoning for his recommendations and the flaws in the current medical system. I think this episode recommends Vitamin D which is a prohormone by the way according to your weight. You may need between 5,000 to 8,000 i.u. per day. Buy a good product which includes K2.

Thanks for this link. Very helpful to me..I bought doctor's best vitamin D3. Is that okay? From Amazon?

Lydia, I think it is essential to have K2 along with the D3. When I first began taking just D3 years ago I developed a small taurus behind a wisdom tooth. D3 will raise calcium and the K2 directs it to the right areas. It is still difficult for me to raise my level so I took therapeutic doses of 15,000 iu twice per week but she prescribed D2 instead. It only raised my level to 37 although in the U.S. the range is 50-100. I use Doctor's Best for many supplements but I have needed to try various D3/k2. You have to find what works for you.

I've listened to doctors over the internet and found them to be profoundly more reasonable basing their comments on research and definitely less on making money. We are the ones who determine how we live so we are the ones who have to find out the healthiest way to do that and it is a fight against our surroundings which have slowly become more and more toxic.

Lydia, Dr. Bergman and many others have much to offer so I would urge you to take in the information and put it to use. He has many videos on You Tube. Keep posting as I think you will find a lot of consensus here at TUK.

That sounds like good advice. About taking supplements for vitamin K2. As I have already bought vitamin D tablets, would you advice that I can buy vitamin K2 tablets on their own, not in combination with vitamin D3? And will I need to take this for life now or only until my vitamin D optimal levels are reached. Do I need a maintenance level once optimal level has been achieved?

I think adding your own K2 is a good idea or you could just buy another D3 with K2 and take them to make the right dose. I'm not sure of the dose of K2 offhand.

I have been wondering why I can't increase my levels when I tan rather deeply and play golf in the sun all summer. I've looked into a condition that seems to store too much glycogen and it has to do with mucin which is a layer in your skin. These seem to be due to an enzyme deficiency. In fact there are many conditions due to enzyme deficiencies so I am attempting to increase those from several difference angles. Digestive enzymes, proteolytic enzymes and unfiltered vinegar all have benefits.

I'll go back to Dr. Bergman who believes the body can heal so I would say if we can stem the autoimmune disease and/or become optimal in treating our thyroid hormones perhaps we can handle the other deficiencies. D3 is one of the few substances found in every single cell of our body so I would strive to get your level as high in the range as you can.

With all the helpful advice on this thread I should soon be able to get my levels optimal. This is such an informative forum. It has given me invaluable information...

I was diagnosed with vit D deficiency a year ago. My level was 17 so severely low :(

I was put on 10,000IU/day for a month Vit D3 (to build it back up) and then 1000IU/day after for maintenance.

I believe this is in line with NHS guidelines. :)

It is yes, Ifound when I was still hypo thought, that it took substantially more than that. The NHS guidance takes no account of thryoid status, Cortisol levels or inflammation all of which make big differences.

I intend to ring the company who did these blood tests, this week, to confirm the results and what they mean with regards to optimal levels, rather than just normal ones, as they suggested for most of the results..

As your D is low you can take 8000 to 10000 IU D3 daily (200 to 250 mcg (micrograms) and test after 6 weeks. You may not be getting sufficient sun which is the real D3.

I would take two daily till you have your bloods checked again the one a day to maintain your levels I have the same problem through malabsorption after stomach & bowel surgery and I buy pure vit 3D from simple supplements .

Was informed that, if a GP prescribes these tablets they have extra strength, as opposed to over the counter ones, to ensure that you don't overdose on those bought tablets. So, once I have spoken to that company, I will my GP and try to get her to prescribe some vitamin D tablets..

A 1000iu D3 tablet will contain 1000iu D3 whether your GP prescribes it or you buy it.

If your GP agrees to prescribe (unlikely unless you are severely deficient ie under 25) then it will be 800iu.

Some of the prescription D3 tablets members have mentioned on here are absolutely awful, cheap, nasty and full​ of unnecessary fillers. Doctor's Best contains two ingredients - D3 and extra virgin olive oil to aid absorption and they are very reasonably priced.

Don't forget that doctors are taught that 'in range' is enough, that there can't be a problem if you are in range. The doctor who put the comments on your private results will have been taught the same. Experienced hypo patients know an awful lot more about their condition and what optimal nutrient levels are and why we need them. The more you read the forum, the more you will understand that most of us are here because we have been let down big time by doctors who don't know enough to help us and keep us ill by sticking to their reference ranges and not taking symptoms into account.

Yes, that's certainly been my experience with doctors and it doesn't cheer me to realise others are having similar problems with theirs when it comes to getting symptoms recognised and medicines prescribed for them..

I did buy doctor's best vitamin D, but it has been suggested that I need vitamin K2 also to aid in this. Is it acceptable to buy that separately from the vitamin D supplements or do they have to be combined to be effective?

I take probiotics too. Will I need to keep taking them still with all these tablets I am taking?

Well, the probiotics do a completely different job to the other vitamins and minerals so yes, continue.

You can take K2-MK7 separately or in a D3/K2 combo supplement. I took mine separately when I was taking the 5000iu dose D3. When I reduced to a maintenance dose I changed to a combo supplement which includes 2000iu D3 and 100mcg K2-MK7.

Not sure if you can answer this one, but just want some clarity, if you can provide some, so as to have the right details when I see my doctor. Due to my having extreme difficulties in regulating my body temperature, would HRT be a good idea to combat this? Or is it best to wait and see how my body copes once the next test results suggest the vitamins are at optimal levels..?

Hi I currently take 5000iu twice a week with k2 and a magnesium spray, as my levels is now at 120

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