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Too Much Vitamin D? -- bottle of vitamin D and vitamin D tablets in the shape of the letter D


Raising low levels of vitamin D has many benefits. Among them is that levels of C-reactive protein (CRP), a marker of inflammation, decrease as vitamin D levels increase. However, increasing vitamin D levels beyond sufficient levels has a slight inflammatory action, as shown in a recent study. And even higher levels of vitamin D can result in hypercalcemia (too much calcium in the blood) with symptoms including constipation, confusion, weakness, loss of appetite and painful calcium deposits. For details about this and extensive information about vitamin D uses and dosage, see the Vitamin D Supplements Review, which includes our latest product tests.

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November 30, 2020

Test Comment

December 8, 2019

wondering why you recommend products that exceed, in some cases significantly, the recommended daily dosage?
December 8, 2019

The recommended daily amount is what is required to maintain an adequate level for most people. But if you are already deficient or have a condition that causes you to require higher ongoing intake of vitamin D (such as a malabsorption disorder), products with levels above the RDA would be appropriate.

August 20, 2019

I've been taking Alive Calcium Bone Formula for years. They recently changed their formula, increasing the Vitamin D to 100 mcg (4000 IU) in a 4 tablet serving. I also take a multiple with 1000 IU in it. I take 3 Alive tablets a day, which will now make my D intake 4000 IU a day instead of 2500 IU. I don't know what to do now. I need to take this plant based calcium because it along with Biosil has reduced and even reversed my osteoporosis, but I am concerned about taking this much Vitamin D on a daily basis.
August 20, 2019

Hi Diane - Good question as this would put you over the upper tolerable intake level for vitamin D at 5,000 IU daily from Alive plus your multi, and that's generally not a good idea. First, do you really need all that calcium from a supplement? Alive has 1,300 mg per day (from 4 pills) which is even more than the current RDA for adults (see Unless you are getting absolutely no calcium from your diet (which is doubtful), perhaps you can take a lower dose of Alive, e.g., 2 pills/day rather than the suggested 4. That would also reduce the vitamin D intake -- although it would still be on the high side. Hope that helps.

August 20, 2019

Thank you. I was so focused on the increased vitamin D content, I forgot they also increased the calcium. I’m still taking the old formula of 1000 mg but only 3 tablets giving me 750 mg of calcium daily. If I take 2 of the new 1300 mg formula, that would give me 650 mg, of calcium, not much less that I’m currently taking. And I used to take 600 mg daily of hydroxyapatite calcium, so that should be OK. And then the vitamin D I would be getting is 3000 mg daily as opposed to the 2500 mg I take now including my multivitamin, a 500 IU daily increase. Would that amount be safe for me to take? My last blood test showed just over 40 for my D level. I’m afraid the 500 IU daily increase would raise that. The NIH states that 4000 IU of vitamin D a day is the upper daily limit for safety.
August 20, 2019

As mentioned, the vitamin D intake would still be high. No need for that, as you are already at 40 ng/mL and going higher would not seem to be a good idea.

July 24, 2016

After reading Consumer Labs original report on the recommended levels, I backed off taking Vitamin D supplements/fish oil other than in a multi, since my last tested levels were quite high. I now eat a small can of locally sourced sockeye salmon, with skin and bones, no salt, about three times a week. Will check my labs when I see my doc next month. I live in Washington state where strong sun shines only a few months a year.

July 17, 2015

Your report states that one can get adequate vitamin D from 15 minutes of sun exposure twice a week.In the summer most people likely get considerably more than that-does one need to be concerned that more than 30 minutes /week in the sun will cause vitamin D blood levels to be too high to be healthy?

May 14, 2017

Skin cancer is a bigger worry from too much sun. Vitamin D overdose is impossible from UV exposure; the skin reaches an equilibrium where the vitamin degrades as fast as it is created.

June 10, 2015

It is not terribly helpful to the average person to read a correct dose expressed as ng/ml. How is one supposed to translate that into a form that a non-scientist can use? As with other supplements, Vitamin D in the bottle is described in terms of "IU" or in milligrams. It would be helpful if ConsumerLab would provide its recommendations for all supplements in terms familiar to the consumer not as ng/ml.
June 11, 2015

Hi Robert - The ng/mL numbers you refer to have to do with levels of vitamin D in the blood, not dosage. We express all dosage information in IU, as that is what you will see on supplements.

June 10, 2015

Check with Vitamin D - optimal levels of vit d3 have been shown in multiple studies to be over 40 ng/ml. I have been prescribing 2-5k IU vitamin d3 gel caps/day for over 10 years now to 100's of patients. I have only had 1 patient have side effects (high calcium and general malaise) in all this time.

A C Sands MD
June 10, 2015

Dear Dr. Sands - Studies do not show optimal levels to be over 40 ng/mL, as you suggest. We recommend that you review the information in the section of our Vitamin D Review entitled "Deficiency vs. Insufficiency and How Much Is Too Much?" (

You may not see immediate adverse effects with high levels, but several studies now show higher mortality rates (i.e., more deaths) among people with levels above 40 ng/mL. The range we suggest of 25 to 35 ng/mL should provide the benefits of vitamin D without risk. We also suggest that you check the unbiased and authoritative opinion of the Institute of Medicine of the National Academies, which considers 20 ng/mL adequate for bone and overall health in healthy individuals.

June 14, 2015

The lab my MD uses says the normal blood level for D, 25- Hydroxy, is 30-100 ng/ml.

I also understand that some neurologists are using higher doses in their patients to help prevent /treat dementia and other problems.
A couple of references: C. Annweiler, et al, "Higher Vitamin D Dietary Intake is Associated with Lower Risk of Alzheimers's Disease: A 7-year Follow-up," Journals of Gerontology Series A: Biological Sciences and Medical Sciences 67, no.11 ( Nov 2012): 1205-11.

D.J Llewellyn, et al, "Vitamin D and Risk of Cognitive Decline in Elderly Persons,"Archies of Internal Medicine 170, no. 13 (July 12, 2012): 1135-41.
July 31, 2015

Hi Virginia - The "standard range" or "reference range" which appear on blood test reports are not based on the expert recommendations of the Institute of Medicine of the National Academies, but reflect levels which the lab has found in 95% of a "healthy" population. However, increasing evidence suggests harmful effects with levels above 40 or 50 ng/mL as discussed in several sections of our Vitamin D Supplements Review (

Also, keep in mind that vitamin D ranges are sometimes expressed as "nmol/L" rather than "ng/mL" - and so the numbers may need to be converted in order to make an accurate comparison. For example, in the second study you cite, deficient levels associated with cognitive decline were expressed as less than "25 nmol/L" which would be less than "10 ng/mL."

January 3, 2016

My lab (LabCorp) as well references vitamin D ranges between "ng/mL" 30-100 as healthy. Based on this my naturopath thought my lab result of 35.6 as needing increased supplementation.
After reading the studies ConsumerLab cites, I plan to back off my supplementation. It would seem the labs need to adjust their healthy range references based on the latest studies.

May 13, 2018

You are overprescribing Vitamin D based on the latest research. I was seeing a functional medicine provider who had me taking 6,000 IU of Vitamin D, and I started experiencing frequent falls, one causing a broken elbow. I didn't put it together until I read the ConsumerLab report. At that time I had been taking 6,000 IU of Vitamin D for a year and had been experiencing frequent falls for about six months (at least 1 or 2 times a month, often in Zumba classes). I backed off to 2,000 IU of Vitamin D a years and a half ago and haven't fallen once since then. My level is about 35 now and I think that's perfect.

May 15, 2018

Thanks for this valuable post Meri. I spend countless hours reading and reviewing and changing my supplements since my integrative dr moved away from Columbus. This is very helpful. Thank you.

May 16, 2018

After increasing my dosage of Vitamin D to 5000 IU I too began falling. When I read consumer labs report on falling being a side effect of too much D I cut back to 2000 IU and after a few months of not falling and my appetite increasing some. I feel better. Thank you consumer labs.

June 29, 2019

I tend to pay most attention to Consumerlab's recommended doses, based on their studies and review of the literature.
My MD's don't agree on Consumerlab's 10-20 nG/mL vitaming D blood titer. One thinks it should be considerably higher!
I conclude that there is either disagreement among studies, or my MDs are ignorant of the recent work.
July 11, 2019

Hi Daniel -- Unfortunately, the range of "normal" applied to blood tests by commercial laboratories and returned to doctors and patients do not reflect what studies show to be sufficient (20 ng/mL), as discussed in the Vitamin D Review at

June 4, 2020

Arthur5764 I've been closely following CL's Vit. D analysis since I also get conflicting information from 2 doctors. I have to laugh that you're referring to the Vitamin D Council as your source -- I mean come-on. Did someone in your medical office draft this comment without noting the irony/fallacy of referring to industry-group research as the only source with which to refute Consumer Lab's ongoing analysis of peer-reviewed research?

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