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Vitamin D


As discussed in the Vitamin D Supplements Review, a good target range for blood levels of vitamin D is 25 to 35 ng/mL, as this coincides with maximum benefit. If you are below this range, there is a rule of thumb for dosage you can follow to get you to your target level -- be sure to take vitamin D with your biggest meal of the day, as you'll absorb more due to fats in your food. Of course, you can also increase levels by a certain amount of sun exposure and/or consuming foods containing vitamin D.

For more details about this, plus doses for specific conditions, and our tests of popular products, see the Vitamin D Supplements Review >>

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January 6, 2016

For those unable to swallow pills, Wellesse makes a liquid Vitamin D/Calcium Supplement which includes the recommended ingredients of both boron, as well as magnesium. It was highly recommended by my husband's orthopedic surgeon. And its made in the USA! They also produce a Vitamin D supplement without calcium. (I would love to see Wellesse tested by Consumer Lab!)
January 14, 2016

Thank you for sharing this, Elizabeth. You may also be interested in our tests of a liquid vitamin D supplement in our Vitamin D Supplements Review:

July 16, 2015

Can anyone recommend a vitamin D3 patch or cream that is effective, I can't take oral supplements.

June 21, 2015

I'm an active 71 yr. old diagnosed @ 48 with discoid lupus. I wear sun block always outdoors and take 2400 IU vitamin D3 daily as part of my supplement regimen. Is this too much?
July 31, 2015

Hi Kay - This amount is below the Upper Tolerable Intake Level for vitamin D for adults; however, the best way to know whether you need supplemental vitamin D, and if so, how much, is to have your blood levels checked. Please see the "How much is too much?" section of the Vitamin D Supplements Review for more about maintaining blood levels of vitamin D in a healthy range:

June 18, 2015

this is the standard range listed on my test results: 30-100 ng/mL; if you are saying this is incorrect and should be nmol/L, then why would my lab report indicate ng/mL?
July 15, 2015

Hi Susan - Please see this section in the Vitamin D Review ( and our response below to Joe.

June 15, 2015

This is confusing and possibly more opinion than hard science. The resent blood test report (March 2015) for my wife recommends Vitamin D, 25-OH, 30 to 100 ng/mL as optimum level and 21 to 29 ng/mL as insufficiency.
June 17, 2015

Hi Dennis - Please see our response to below to Joe, regarding reference ranges on blood tests.

June 15, 2015

My Dr has me taking 4000 IU's of Vitamin "D" a day. My blood test reports 67 NG/ML which is very high by you standards. But the "STANDARD RANGE" shown for this blood test is 20-100 NG/ML??? Are we talking about the same test??
June 17, 2015

Hi Joe - Yes, we are talking about the same test and the evidence would suggest that you are taking far too much vitamin D. 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 ( Less than 15 years ago, before people started taking large amounts of vitamin D, a level like yours was extremely rare.

June 11, 2015

To get from 20 to 30 ng/dl, I had to take about 6 times what your rule of thumb suggests should accomplish it in six weeks. I am healthy and was taking an approved product with my largest meal. So presumably it would have actually taken me about nine months (36 weeks) to get there following your rule. Once at 30, though, the amount stated in the rule of thumb has proven about right for keeping me at that level.

June 11, 2015

I also disagree with you statement that the known benefits of vitamin D fall into the serum range of 25-35 ng/mL There is clear evidence that for whites under age 50, bone density increases as serum 25-OH vit D levels rise without any upper limit. (Bischoff-Ferrari.2004.AJM.116.634 see p 637 left bottom - "In younger whites, there was no identifiable threshold above which 25-hydroxy vitamin D levels were not associated with additional increases in bone mineral density.") Also there is clear evidence in the breast cancer literature that breast cancer risk decreases up to 52 ng/mL certainly not stopping at 35 (Garland.2007.JSeroidBiochemMolBio.103.708). Members on the vitamin D panel of the IOM have admitted in a large Q&A forum that their panel had no hard evidence for the numbers they chose to recommend. This has been a hot political football in the IOM for decades, and their recommendations have never been based on the hard, best evidence of the vitamin D research community.
June 12, 2015

Hi Craig - We must correct you. The Bischoff study you mention measured vitamin D blood levels in nmol/L, not ng/mL. Be aware that 2.5 nmol/L is equal to just 1 ng/mL. If you do the conversion, you'll see that the study found that, compared to people with the lowest levels, "most of the improvement occurred" at concentrations of just 9 to 16 ng/mL, and "there was further improvement at levels of" 16 to 37.6 ng/mL. As noted above, a target level of 25 to 35 ng/mL seems prudent, providing maximum benefit without the risk associated with higher levels. Let's help people and not lead them to harm.

June 11, 2015

I read that due to aging the production (Vit. D) capacity of our body would be lowered. Even regular exposure will not suffice. Under such circumstances one may have to take vitamin D3 supplement during old age to meet out our body's regular requirements. Please comment on this.
June 17, 2015

Hi Subbiah - We've now added an answer about vitamin D and aging here:

June 10, 2015

Blood level of vitamin D between 25 and 35 is way too low. It should be between 50 and 80,
especially if you have cancer or health issues. Vit d is safe under 100.
June 11, 2015

Hi Micheline - Unfortunately, the very high levels you suggest are associated with increased risk, not increased benefit. We have heard from a number of people making suggestions similar to yours, which have no basis in fact. Perhaps a source of confusion is that blood (plasma) levels of vitamin D (25-hydroxyvitamin D or 25-(OH)D) can be measured in either or ng/mL or nmol/L. As explained in our Vitamin D Review (, they are quite different: 1 ng/mL equals 2.5 nmol/L. In the U.S., most laboratories use ng/mL, while those in Canada have used nmol/L. The Institute of Medicine recommendation is 20 ng/mL (which would be 50 nmol/L ) or more, but not above 49 ng/mL - and there is evidence that even levels above 40 ng/mL are associated with less benefit and more harm than moderate levels. Don't overdo it.

Jill 5797
June 15, 2015

I am 70 female and was diagnosed with hypercalcimia because I was taking high doses of D(other possible health problems were ruled out by blood work, etc.) I took D based on what I had read in popular press and heard on radio programs. Oddly enough I had to press my doctors as to why I had these elevated calcium levels.
July 31, 2015

Hi Jill - We appreciate you posting your experience. There seems to be a great deal of misinformation causing people to overdose with vitamin D. If you experienced hypercalcemia due to vitamin D, your blood levels were likely extremely high. What is also of concern is that even lower blood levels (more than 40 or 50 ng/mL) may be doing long-term harm, as suggested by several studies mentioned in our Review. As you've learned - you can get too much of a good thing.

April 22, 2021

My Vitamin D Level is 30.7ng/mL and was flagged as low. The normal range on the blood test was shown as 31-100 ng/ml. My doctor wanted me to up my levels and prescribed D2 Ergo 50,00IU's once a week for 12 weeks. I took one dose and couldn't sleep and developed a rash. I'm no longer going to continue that protocol. However a friend recommended 4,000IU D3 for 3 months plus magnesium 300MG and Vitamin K 100MG. Does this sound doable to get my numbers up into the healthy range. I know according to your website, I'm already in a healthy range but my health care system labels it as slightly low. Please advise.
April 23, 2021

Please read our Vitamin D Review carefully. What you are proposing would not seem to be beneficial and could be harmful due to excessive vitamin D and magnesium (unless you're signifcantly deficient in magnesium -- see our Magnesium Review).

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