Best Time to take Vitamin D3?

Hi, I am currently on a maintenance dose of 10,000 D3 a week, taking one 10,000 pill on Mondays. I've read that it doesn't matter if I take it in the morning with breakfast, which is around an hour after taking my thyroid medication. I've also read that it should be taken 4 hours apart from the thyroid medication. Thought I'd ask you kind people about this. Thanks in advance!

32 Replies

  • You should take vitamin D 4 hours away from thyroid medication.

    Most people don't eat food with sufficient fat in for breakfast so it is better to take vitamin D at lunch time as it is better absorbed with fat. In nature food sources of vitamin D3 tend to be fatty e.g. oily fish for that reason.

  • Hi.....if you purchase vit D3 in oil capsules the uptake is maximised....but you can do this via eating some oily food too...when taking tablets.

    Ive never heard of any need to take it seperately from thyroid meds. The four hour rule is applied to iron & calcium supplements.

    As far as timing is concerned. Am not aware of any specific best times. Vitamin D is stored in the body and therefore the body has ready access to vitamin D to use as needed. I was under a Consultant metabolic bone specialist in the NHS and no mention of timings or supplements to avoid or specific times to take very high doses of vit D or maintenance doses after that. Infact some NHS vitamin D tablets contain both calcium and vitamin D and These were the ones prescribed for me when I moved onto a maintenance dose.

    Hope this helps....

  • Many doctors even specialists don't tell you timing for medication let alone supplements.

    However all over this forum the advice is not to take vitamin D with thyroid meds.

    Also some GPs will prescribe vitamin D and calcium tablets even though the NHS advice in most areas and NICE guidelines say this isn't advised unless the patient has an issue with their calcium levels.

  • Blue bug I dont have an issue with my calcium levels but I do have an issue with the density of my bones due to an effect of a prescribed medication I cant avoid as advised by a bone specialist I take calcium and vitamin D together. I dont understand why this works better then just having plenty of calcium in my diet & taking vistamin D but the results are that the combined treatment has strengthened my bones far more then taking vitamin D3 on its own.

    Whilst I agree GPs have limited knowledge I do heed a Consultant whose specialsim is in bones. I agree that with Endocrinologists there is great debate over aspects of treatment for hypothyroidism which has casued a considerable number of patients to be forced to go elsewhere to get optimal treatment but this it isnt the case in all specialisms.

  • Wavylines,

    The 4 hour gap applies to vitamin D too. I'm sorry I don't have the link to the article in which I read it.

  • I don't believe it has. Vit D can be taken with food, or without food, it is both fat and water soluble (Dr. Holick - The Vitamin D Solution). You do not need to wait 4 hrs, away form thyroid hormones.

  • Mariolewna,

    VitD is fat soluble and is a pro-hormone which is why it should be taken 4 hours away from Levothyroxine.

  • Mariolewna,

    The article states that vitD is fat soluble and twice mentions that Synthroid should be taken 4 hours away from supplements.

  • Well Ive just read it and it says 30mins which is the standard for all food where levo is concerned, I do not get the 4 hour rule? Sorry to query but am concerned.

    It also looks at vit D level being commonly low in hypothyroidism -this is diffferent to blocking uptake of a thyroid med. its also reads as if higher levels of vit D increase uptake though this is not proven thereby recommending thyroid levels being monitored if you are on vit D. It also says far more research is need to look into all of this.

    I really do not think it is clear cut.

  • mariolewna There is a water soluble form of Vit D - Micellized Vitamin D3 Liquid, which is different from the fat soluble D3 frequently mentioned here in the form of softgels (or capsules). There has been a study to compare the absorption rates of the micellized D3 and the fat soluble D3

    And although this link talks about 'water soluble Vit E', it does refer to normally fat soluble vitamins in general and concludes that "once it is absorbed into the body it would appear to behave as a fat soluble vitamin does"

    And apparently water soluble Vit D is present in human breast milk, not that any of us will be supplementing with that.

    So it depends which form you take, a D3 softgel is not water soluble but a water soluble form would still appear to behave as a fat soluble one ie excess will get stored in the body rather than pee'd out

    Fat soluble vitamins that get stored: A, K, E, D

    Water soluble vitamins where excess is pee'd out: B, C

    I agree with Clutter that Vit D should be taken 4 hours away from thyroid meds, along with iron, calcium and magnesium.

  • One article suggesting a four hour gap between Levo and D3:


    Can we take levothyroxine and vitamin D side by side

    In my opinion, each and every supplement should be separated by 4 hours with the thyroid medication to avoid decrease in absorption of levothyroxine systematically . If their is changes in absorption of levothyroxine in patients then dose adjustment is needed to maintain the same therapeutic effect required to provide the biological effect to avoid any side effects in the body system and lead the body functioning smoothly.


    And this article about interactions with Levo mentions multivitamins and minerals rather than specific supplements:


    Using multivitamin with minerals together with levothyroxine may decrease the effects of levothyroxine. You should separate the administration of levothyroxine and multivitamin with minerals by at least 4 hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.


  • Fro completeness see link below :-

    As far as Im aware there is no actual reported interaction between the two.......unlike calcium and iron where there is an interaction

  • Ditto to Waveylines. Also vitamin D is best taken later on in the day, or later on in the evening - preferably with an evening snack that contains some fat (a normal amount in a normal meal is sufficient) since Vit D is fat-soluble and this aids absorption. This is because vit D aids sleep and to get the best effect, you should take it later in the day.

  • Actually some people report vitamin D taken in the evening disrupts their sleep which is why people are told to take it earlier.

  • I read the most recent research says to take vit d3 with your evening meal, making sure they is some good fat within the meal, e.g. Butter or coconut oil, if not eat some anyway. Best to take vit k2 at the same time. Research from 2013 said to take a probiotic with it too. Lots of people also recommend magnesium to be taken with it too.

    I always forget, brain fog, so I just take when I remember, but it's usually the evening.

    I hope it helps

  • Vitamin D is a hormone, so take it >4 hours away from your THs to prevent it interfering with absorption. I take my daily dose late afternoon with full fat kefir, for vitamin K2, & seeds & nuts for fat, which helps absorption.

  • I like to keep things as easy as possible so the levo is taken around 8am. Other tablets and supplements I start after my lunch with the vitamin B complex (only take this every other day now) and methylcobalamin sublingual. Selenium with teatime snack and finally the Vitamin D3 and K2 after evening meal with a fish oil caplet and rounding off with magnesium citrate about an hour before bed. Not forgetting a Macushield caplet which is meant to help slow down the first signs of age-related macular degeneration that was spotted late last year. There are occasionally others but I will only supp them for say 3 months on and 3 months off. They are always taken well away from the levo.

    I certainly don't take a lot compared to other poor souls but hubby has suggested that the Bournemouth Symphony Orchestra might use me as a set of maracas next time the perform Bernstein's West Side Story. :D

  • Wow this has generated some interesting discussion. I would be interested to see the research that shows a proven link between up take of vitamin D and other supplements.

    Its generally advised to take levothyroxine on its own. I take a dessicate thyroid. I do take half of my dose first thing in the morning therefore at fasting and wait for an hour before eating. Im afraid the other two doses are not lIke that due to plain practical issues of needing to eat! However I do keep my calcium supplement 4 hrs away from my NDT as thats proven to interfere.

    Must admit Ive not been great with my k2 but I do eat lots of greens containing k2 so hopefully I haven't caused myself a

  • As others have mentioned you need K2 with D3 to make it go to your bones not your arteries or heart valves. Did the Specialist tell you this?

  • Is there any scientific evidence for this? Also can I simply have a glass of kefir with the one 10,000 D3 a week I take or I need daily K2 supplementation? Thanks.


    Lots of info on Dr. Mercola site and he's a doctor and more.

  • I've got a headache!😀

  • Just to add to the various permutations of taking meds and supplements 😊

    I take D3, K2, selenium, B complex, B1, B12 (probably something else too but it's late) with breakfast which usually is strained Kefir so it's like thick yoghurt, with fresh chopped fruit which I 'cook' for 2 mins in some coconut oil. Washed down with the Kefir 'whey'.

    Mid afternoon I take Magnesium and C. I eat liver twice a week.

    I take levo (cut into pieces) at bedtime about 3-4 hours after evening meal.

    Not wanting to tempt fate but all going in the right direction 😊 thanks to the wonderful help from you guys.

  • Thanks everyone for the advise! Just wanted to also quickly ask, if I take a B12 sublingual does that need to be 4 hours apart from the Synthroid as well? Thanks.

  • No, it's iron, calcium, magnesium and Vit D that should be 4 hours away from Levo. Other supplements and medication is two hours.

  • Thanks. Last but not least, you guys have been very helpful. I'd like to buy K2 supplements online today. What is the recommended dose? I'd be taking one Vitamin D3 10,000 a week.

  • From

    " For every 5,000–10,000 units of D3 being recommended and tested for, we are recommending 100 mcg of K2 mk7 to be sure and prevent the inappropriate calcification that higher doses of D3 alone could cause. "

    Vit D Council recommends 120mcf for males

    And a couple of combo D3/K2 supplements I've checked led vary between 90 and 220mcg

    By the way, is there a reason you are taking 10,000iu weekly rather than a lower dose daily or alternate days?

  • I like to keep things as simple as possible, and it's far soluble. The doctor gave me a prescription to get the 10,000 unit supply from the pharmacy.

  • I was also told and read that because vitamin D is stored in the body you can take it either daily or a higher dose once per week.

  • I have looked and looked and cannot find any scientific research to show an interaction between vit D and levothyroxine. Can someone please post the research behind these claims?

    Its bad enough doing what has been proven scientifically then adding to the mix.

    Please also be aware that there is K2 in leafy green it does depend how up you on your greens.

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