What is a healthy vitamin D blood level?

When measuring blood levels of vitamin D (as 25-hydroxy vitamin D), what constitutes a desirable level?

There's no study that directly examines this question, no study that enrolled thousands of people and assigned a placebo group and groups receiving escalating doses of vitamin D and/or achieved higher levels of vitamin D, then observed for development of cancer, diabetes, depression, heart disease, multiple sclerosis, osteoporosis, osteoarthritis, etc. Such a study would requires many thousands of participants (particularly to observe cancer and multiple sclerosis incidence), many years of observation, and many tens of millions of dollars. Nope, only a drug company could afford such costs.

So we have to piece together various observations and extrapolate what we believe to be the ideal level of vitamin D. Epidemiologic observations in several cancers (breast, colon, prostate, and bladder) suggest that a 25-hydroxy vitamin D level of 30 ng/ml or higher is desirable (with less cancer incidence above this level). Other data suggest a level of 52 ng/ml or greater is desirable. Unfortunately, much cancer research looked at intake of vitamin D from food and supplement sources, rather than actual blood levels. We also have to factor in the great individual variation in vitamin D metabolism, with a single dose yielding variable blood levels (as much as a 10-fold difference). There's also the variation introduced by vitamin D-receptor variation (genetic polymorphisms).

A new study using vitamin D administration helps chart the desirable levels of vitamin D.

Vitamin D supplementation reduces insulin resistance in South Asian women living in New Zealand who are insulin resistant and vitamin D deficient - a randomised, placebo-controlled trial.

In this New Zealand study, 42 women (23 to 68 years old) were given 4000 units vitamin D, 39 women given placebo. Median 25-hydroxy vitamin D levels increased from 21 nmol/L (8.4 ng/ml) to 75 nmol/L (30 ng/ml). Both HOMA (a measure of insulin sensitivity) and fasting insulin levels improved, with greatest improvement seen at 25-hydroxy vitamin D levels of 80-119 nmol/L (32-47.6 ng/ml) or greater.

We also know that a vacation on a Caribbean beach in a bathing suit will increase vitamin D blood levels to the 80-110 ng/ml range without ill-effect (at least in young people who maintain the capacity to activate vitamin D in the skin, a phenomenon that declines as we age).

So do we really know the truly ideal level of vitamin D to achieve? I believe that, given the above observations, it is reasonable to extrapolate that the ideal vitamin D blood level likely lies somewhere above 50 ng/ml. We also know that vitamin D toxicity (i.e., hypercalcemia) is virtually unheard of until vitamin D blood levels approach 150 ng/ml, and even then is inconsistent. The health benefits of vitamin D supplementation are so tremendous, that I am not willing to wait for the prospective data to explore this question fully. For now, I aim for a blood level of vitamin D of 60-70 ng/ml (150-175 nmol/L).

Comments (32) -

  • karl

    11/9/2009 3:29:40 PM |

    The question I have, is 60-70 ng/ml enough? Are we being too conservative?

    I'm thinking a target of 80 ng/ml might eventually pan out.

  • Daniel

    11/9/2009 4:17:11 PM |

    There is also Melamed's study showing a sharp increase in mortality above 50ng/ml or so.  Small sample size and residual confounding probably, but worth considering nonetheless.

  • Anonymous

    11/9/2009 4:30:31 PM |

    I wonder if it is really true that Vitamin D production decrease is really a function of aging, rather than a consequence of eating the SAD for so long.

    It would be very useful to have a properly conducted study to address this question. Could elimination of gluten, excess fructose, correcting O-6/O-3 imbalance, and other hyperinsulinemia/inflammation sources in even the aged allow large amounts of D3 production?

  • mike V

    11/9/2009 7:26:17 PM |

    Progress report:
    Over about 5 years I have gradually ramped up vitamin D3. Initially, tablet form. Last 18mo capsule form.
    Started noticing cold/virus improvements over entire period.
    Finger/prick Lab work: (GrassRootsHealth.com)
    Mar 2009  50ng/dL  prior dose 4000iu 3mo.
    Sept2009  60ng/dL  6mo dose   6000iu

    Current dose for H1N1 Winter 8000iu. Target: 70-80ng/dL by next fall.
    Age 73
    Weight 190
    Race W.
    Sex  M
    Meds. Armour Thyroid.
    Colds: Only hints lasting two days
    early in the season. Otherwise cold/flu/infection free.
    Hospitalizations: None.  
    Vaccinations none in five years.

    Hope some one finds this useful.

    In my carefully considered (but not so humble) opinion, if most people would follow Dr Davis's recommendations, most US health care cost and availability problems would disappear in less than a generation, Bill or no Bill.


  • AMK

    11/10/2009 2:32:07 AM |

    Supplements can be of great help in getting rid of free radicals  to our body.  A good source of vitamins and antioxidants to suffice what we lack from food intake.

  • mongander

    11/10/2009 2:33:20 AM |

    I take 10,000iu in winter and 5,000iu other seasons.

    My last grassroots test: 79 ng/ml.

    Age 70

    Never get colds or flu but have medium grade prostate cancer.  Doing "watchful waiting".  May get foreign "HIFU" treatment.

  • ob

    11/10/2009 6:07:01 AM |

    The perfect blood range will proove to be that of people wearing little clothing in a sunny climate who are tanned and avoiding being burnt ie 80-100ng/ml. Looking at it through the lens of evolution (since animals can out of the sea and forwards)- it has to be that this is what we will be best adapted too.

  • Helena

    11/10/2009 4:06:21 PM |

    I like it! I had the 76ng/ml last month when I checked (first time in my life actually checking).

    I have been taking at least 5000 IU every day (liquid) for the past year and a half. But have recently increased it to 11000 IU once or twice a week. I can feel the winter is coming.

    Thanks for a much important post as we are getting closer to winter and flu season.

  • scall0way

    11/10/2009 8:10:02 PM |

    6 months of supplementing with 5000IU D3 gelcaps daily has gotten my D up to a level of 58 (it was 46 after 8 weeks of supplementing)so I'm getting there. I'm just trying to decide if I should bump the dose. It's just trying to establish priorities now that I know I'll be losing my job, my income and my reasonable health insurance sometime in the next few months.

    And I was just diagnosed with Hashimoto's disease this WEEK, so now have to contend with getting my thyroid sorted out too. Always some darn thing or another. :-D

  • mike V

    11/11/2009 5:40:00 AM |

    I empathize with you in you situation.
    If you require thyroid medication, ask your doctor for for Armour Thyroid.
    Continue to follow Dr D's recommendations regarding Vitamin D3, fish oil, iodine.
    Consider curcumin/turmeric, quercetin, NSAIDS. Avoid omega 6 etc
    Hope you get Hashimoto under control before insurance ends.
    Maintain vitamin D3 at all costs. Should help to regulate autoimmunity. Best bang for the healthcare buck.
    Good luck!
    Mike V
    Visit drbganimalpharm.blogspot.com

  • Chloe

    11/11/2009 6:57:14 AM |

    March 2007 D test was 7 ng/ml, and after supplementing with 8000 units Carlson's D3 per day, my grassrootshealth test is 94.  Yahoo! Going to keep it there as I have had SAD (the seasonal kind and the dietary kind in the past) for over 60 years, and the vitamin D supplementation has helped with the seasonal kind of SAD (along with bright full-spectrum light in the morning and blue blocking glasses at night).

  • Lere

    11/11/2009 7:30:36 PM |

    Vitamin D and homeostasis " a homeostatic mechanism keeps the level of vitamin D in our bloodstream within a certain range. When UV-B light is always intense, as in the tropics, the level seems to be 50-75 nmol/L in young adults and progressively lower in older age groups. The more sunlight varies seasonally, the more the body will produce vitamin D in summer in order to maintain at least 50 nmol/L in winter—a level well below the recommended minimum of 75 nmol/L and even further below the 150 nmol/L now being advocated by vitamin-D proponents.

    This homeostatic mechanism breaks down if we daily ingest 10,000 IU of vitamin D or more (Vieth, 1999). It seems that the human body has never naturally encountered such intakes, at least not on a continual basis.

    In a recent review article, Robins (2009) presents evidence for a second homeostatic mechanism. Even when the level of vitamin D varies in the bloodstream, the second mechanism ensures that these divergent levels will translate into the same concentration of the biologically active 1,25-(OH)2D metabolite."

  • Valerie

    11/11/2009 11:01:13 PM |

    Dear Dr. Davis,
       Are you still recommending Vitamin D for Aortic Valve Stenosis? Do you have any updates on whether it helps the calcification to regress, as you mentioned in your articles from 2007? I just found out I have a very severe case of this, and your blog is the first place I've seen any hope of improving it other than heart valve replacement. But I also saw that some people say Vitamin D makes it worse! It's so hard to know what to do. So could you let me know how it's going on this since 2007? Have your patients gotten better from the Vitamin D and the calcification regress? At the moment I don't take any Vitamin D at all. Tx very much.

  • Dr. William Davis

    11/12/2009 2:20:35 AM |

    Hi, Valerie-

    I am definitely continuing to advise vitamin D normalization for nearly everybody, including those with aortic valve disease.

    I now have about 30 people who have normalized vitamin D and have aortic valve disease. The overall trend is a dramatic slowing of deterioration. Vitamin D does NOT cause worsening unless you take it to toxic levels. That is what is causing the confusion: Rat studies in which toxic levels of vitamin D were used to cause aortic valve disease.

  • sue

    11/14/2009 1:47:45 AM |

    Dr. Davis,
    Do you know whether D3 supplementation can affect the BU/CR Ratio on a CBC? I read that steroids can cause a rise in BUN and that D3 is considered a steroid?

    I finally got my D3 levels up to 57 ng/mL with daily 6,000 IU d3 (from mid September)and also added fish oil a month later. Had blood levels checked end of October and got a flag on the BU/CR ratio of 25.0, lab range 6-22. BUN was 17 and Creatinine was 0.68. No other chemistry components outside normal range.

    I should mention that I am also post-menopausal and on HRT - (Divigel transdermal & Prometrium) -- and mildly hypothyroid (Synthroid 50 mcg).

  • moblogs

    11/14/2009 4:27:57 PM |

    I'm 30yrs old from London, England with naturally tanned skin and have a maternal history of primarily bone and heart problems.
    My pre-supplement D value was just 10nmol/L. 5000IU took me to 76nmol/L, whereas 10000IU took me to an acceptable 141nmol/L.
    Not only has my PTH decreased but my second ever DEXA scan (I am given them as precaution) showed a 7% increase in bone density even though it was fine before and my cholesterol profile changed to show an increase in HDL and a reduction in cholesterol ratio. Of course particle size isn't measured here but I'm sure vit D isn't dis-servicing me by what I've observed so far.

  • Anonymous

    11/14/2009 10:58:22 PM |

    Dr. Davis,

    I've tried 3 different forms of supplemental Vitamin D(dry tabs, gel caps and now liquid ddrops). For some reason I seem to experience slight tightness of chest and shallow breathing after I take any form of vitamin D. The higher the dose, the more pronounced the side effects are and for a longer duration(last weekend I took 4000iu's and it seemed to last for most of the day).

    Would you advise I stop supplementation? I was considering taking it before bed so that any minor side effects wouldn't be as noticeable when I sleep.


  • Dr. William Davis

    11/15/2009 1:02:36 PM |

    Hi, Mo--

    Great results. I wished that I'd known about vitamin D at your age.

    I'm grateful that we finally have come to appreciate what an extraordinary thing vitamin D is.

  • Dr. William Davis

    11/15/2009 1:03:58 PM |


    Once in a while, I'll see somebody with sternal (breastbone) awareness of vitamin D deficiency or replacement, both resulting in pain. While harmless, it can be very frightening.

    However, you might still want to consult your doctor about this. Hopefully, he/she understands how important vitamin D replacement is.

  • Anonymous

    11/15/2009 10:20:29 PM |

    Thank you Dr. Davis.

    Unfortunately my current physician isn't too receptive to the increasing popularity of Vitamin D these days.

  • Neonomide

    11/15/2009 10:54:13 PM |

    Heike-Bischoff-Ferrari et al. (2008):


    As you can see, over 50 year old white-skinned persons who had higher than 100 nmol/l had _lower_ bone mass density than those about at 100 nmol/l.

    I think this should be taken into consideration when determining optimal 25(OH)D levels, don't you think ?

    Full text here:

  • Anonymous

    11/16/2009 1:37:39 PM |

    Dr. Davis, I've been supplementing 10k iu per day for nearly 1 year using a gel cap supplement. I still only managed to achieve a level of 52 ng/ml. Is it safe to take a higher dosage. In your practice have you found this to be common. I have had my gallbladder removed and use nexium for GERDs. Otherwise im healthy 50 year old male. Thanks for taking the time to read.

  • Olga

    12/2/2009 3:42:01 PM |

    Hi Dr. Davis:
    I had an unnecessary hemithyroidectomy about 5 years ago for a benign goiter after my second pregnancy (both winter pregnancies) and have felt unwell ever since.  I could never find a dose of synthroid that would work well.  I would need a dosage adjustment upwards in the late fall and then in the spring I would feel hyper and need to lower the dose.  This went on for 3 years in a row and I finally asked my Dr. if this could be due to Vitamin D since it's the only seasonal variation that made sense to me.  She of course said that was unlikely.

    I did lots of reading on the topic and found that many people that have half a thyroid don't need supplementation, so I asked her if I could try going off the meds to see if my thyroid could make enough hormone on it's own.  Other than being tired and having heavy periods I felt not too bad.  At 3 months I was iron deficient so I started consuming liver once or twice per month for about 3 months and started feeling ill with joint pain, digestive problems, fatigue, insomnia.  It took me another 6 months to figure out that people who have familial hyperlipidemia have a tendency to overdose on levels of vit A that would be fine for most people.  Here's are a few of the papers that finally gave me some answers:


    And again the symptoms worsened in the fall.  I developed a cold that lasted 4 months!  Finally I insisted my DR. check my vitamin D level and in September it was 72 nmol/L.  She was surprised and put me on 1000 IU of vit D3.  Over the next year I waffled between taking synthroid or Armour and going off it because I felt so awful and didn't know what was wrong.  I think the Vitamin A was confounding the recovery process.  A major breakthrough came a couple of months ago.  I was on the lowest dose of synthroid (in the fall of course), my thyroid function had improved enough over the past 2 years that the lowest dose was enough, and I started taking 5000 IU of vitamin D.  Within 2 weeks, I started having severe hyperthyroid symptoms.  I told my Dr. that I thought the vit D was improving thyroid function and that I wanted to go off the synthroid yet again.  Within 2 weeks the hyper feeling slowly subsided and I am waiting 3 months before having my thyroid levels and vit D checked.  My only remaining symptoms are joint pain (less now than a year ago), mild fatigue, insomnia, and constant hunger despite being on a low carb diet (which made me feel great before the surgery).  My mood is much better and my mental clarity has improved.  Over the past year my TSH off medication has dropped from 12 to 4.  I am hoping that in 3 months or so it will be almost normal.

    Here is one of a few papers I found about low levels of Vitamin D following a hemithyroidectomy:

    I had my iodine levels tested and they were found to be normal.  I wonder now if the nodule was cause by low levels of vit D during two winter pregnancies along with a prenatal supplement which was high in Vitamin A relative to Vitamin D in a Vitamin A toxicity susceptible person.  I found a few papers on-line which suggest vit A can be a cause of thyroid goiter.
    Thanks for this excellent blog.

  • Bumper

    12/8/2009 4:35:13 AM |

    How or what may I take to get adequate iodine? Tks.

  • Olga

    12/8/2009 5:05:51 PM |

    Hi Bumper:

    The best methods of getting iodine are Lugol's iodine, Iodorol, or Kelp.  Salt isn't really a good source, the iodine is volatile and eventually dissipates.  You should have an iodine loading test done to determine if you are in fact iodine deficient.  You can order one on-line yourself, or go to a naturopathic Doctor who can order one.  I hope this helps.

  • Di

    12/21/2009 7:50:27 AM |

    I am so pleased to have found this blog! I was diagnosed with mild arotic valve stenois and afraid there was no treatment approach, until reading about Vitamin D here. I have am taking between 1,000 - 2000 i.u. of D3 per day for reducing fatigue and improving calcium absorption(I also have osteopenia and take Fosomax once a week; am age 59.) Dr. Davis, how much more Vit D can I safely take? I do not know how to to calculate the ng/ml levels that I am reading about here. How would you suggest I get started with this approach?

  • DougCuk

    1/11/2010 1:00:31 PM |

    The only way to tell how much Vitamin D3 supplement you need to take is by a blood test - either via your doctor or take a look at this website www.grassrootshealth.net/ which offers cost price blood tests.

    I have put together a summary of current advice on Vitamin D blood levels and guidance on response to supplement intake: www.stargateuk.info/vitamind/Blood_Levels.htm

    For a general overview of Vitamin D health benefits take a look at my website: www.stargateuk.info/vitamind

  • Henry Lahore

    1/15/2010 4:10:29 PM |

    Excellent article

    You can find in-depth information at http://www.henrylahore.com/VitD.html.  

    Actively creating a wiki where everyone can share vitamin D information.

  • Tracie P

    1/16/2010 2:19:04 AM |

    Okay, I am totally new to the Vitamin D issue.  My sister had a full workup and her dr found that she had very low levels of Vit D (19).  She's always extremely tired.  I have been working out with a personal trainer and decided to go to the dr to get a full physical (I'm also tired often but thought it was because I have a 3yr old).  I specifically asked about Vit D and the dr said they don't normally test it.  I told him I was tired often and he said that was a symptom and ordered blood work.  Well, apparently mine is a little lower than my sister's.  The dr said my Vit D levels should be between 35-100 and mine was 16.  Now, what should I do???  Where should my levels be (I'm almost 40, white, healthy).  Appreciate any help!

  • Anonymous

    2/11/2010 8:23:08 PM |

    This is the most comprehensive info re: vitamin D levels I've found on line. Most posts are 50-70ng/ml and bumping up, but my D Total is 19. My dr's asked me to see her, but can she prescribe anything I haven't already learned: take 1-2000 iu's D, cod-liver oil/more fish & sun? Thx!

  • Anonymous

    10/20/2010 6:22:14 AM |

    I'm concerned that my vitamin d is too high! It's 84.9 ng/ML. I'm a 27 year old female and take 2000 IU per day (along with whatever vitamin d is in two citrical pills). Should I back off? Thoughts?

  • buy jeans

    11/3/2010 10:30:38 PM |

    We also know that a vacation on a Caribbean beach in a bathing suit will increase vitamin D blood levels to the 80-110 ng/ml range without ill-effect (at least in young people who maintain the capacity to activate vitamin D in the skin, a phenomenon that declines as we age).