Vitamin D: More Is Not Always Better | Chris Kresser
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Vitamin D: More Is Not Better


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Have you been told you need more vitamin D? Healthcare practitioners are increasingly aware of the risks of low vitamin D levels, but many are not aware that high levels of vitamin D can have toxic effects. Read on to learn the risks of over-supplementation, what factors determine your optimal vitamin D level, and the many reasons to get sunlight exposure beyond just vitamin D.

optimal vitamin d levels
Testing your vitamin D levels is essential to prevent vitamin D toxicity.

Vitamin D is critical for health. Virtually every cell in the body has a vitamin D receptor, which, when bound to vitamin D, can influence the expression of more than 200 genes (1, 2). Vitamin D promotes calcium absorption in the intestine and maintains calcium and phosphate levels in the blood, protecting against osteoporosis, rickets, and bone fracture (3, 4). It also regulates immune function, cell growth, and neuromuscular function (5, 6).

With the many roles that vitamin D plays in the body, deficiency of this fat-soluble vitamin is a real cause for concern. Vitamin D deficiency has been found to increase the risk of heart attack, cancer, diabetes, asthma, and autoimmune disease (7, 8, 9, 10, 11, 12). Our modern indoor lifestyle limits our sun exposure, and we can only get a small amount of vitamin D from diet (13). According to the lower boundary of the U.S. lab range of 30 ng/mL, as many as 70 percent of Americans are considered deficient (14, 15).

It’s great that awareness about vitamin D deficiency is increasing, with more doctors than ever testing vitamin D levels. However, like many nutrients, vitamin D follows a U-shaped curve, meaning that both low levels and very high levels are associated with negative health outcomes (16). Unfortunately, few practitioners are aware of the dangers of vitamin D toxicity, and many just test serum vitamin D once and recommend a daily 5,000 or 10,000 IU supplement to their patients.

In this article, I’ll discuss the risks of over-supplementation, why you should get most of your vitamin D from sunlight, and the reasoning behind my current approach to vitamin D.

Risks of Excess Vitamin D Supplementation

Vitamin D status is measured by 25(OH)D in blood. We’ll dive further into vitamin D metabolism later, but for now, just understand that this is the precursor to active vitamin D and is generally considered the most accurate single marker to assess vitamin D status. The U.S. laboratory reference range for adequate 25(OH)D is 30 to 74 ng/mL, while the Vitamin D Council suggests a higher range of 40 to 80 ng/mL, with a target of 50 ng/mL (17).

But a large body of evidence in the medical literature strongly suggests that optimal vitamin D levels might be lower than these figures. There is little to no evidence showing benefit to 25(OH)D levels above 50 ng/mL, and increasing evidence to suggest that levels of this magnitude may cause harm. Consequences of vitamin D toxicity include heart attack, stroke, kidney stones, headache, nausea, vomiting, diarrhea, anorexia, weight loss, and low bone density (18).

Furthermore, in most studies, taking vitamin D supplements does not decrease risk of death, cardiovascular disease, or other conditions. Based on an exhaustive review of over 1,000 studies in 2011, the Institute of Medicine recommends a much more conservative range of 20 to 50 ng/mL (19).

Some research on Israeli lifeguards suggests that, contrary to popular belief, vitamin D toxicity from sunlight alone (in the absence of supplementation) is possible (20). That said, it is  much more difficult to achieve toxic levels through sun exposure alone. Sunlight is the optimal source of vitamin D, and has numerous  benefits above and beyond improving vitamin D status.

Can your vitamin D levels be too high? I think so.

Beyond Vitamin D: The Many Benefits of Sunlight

Vitamin D is really just the tip of the iceberg when it comes to the benefits of sunlight. A recent 20-year study following 29,518 subjects found that those individuals avoiding sun exposure were twice as likely to die from all causes (21). While this study did not assess vitamin D levels, findings from other epidemiological studies suggest that this cannot be accounted for by the increase in vitamin D production alone.

Indeed, humans make several important peptide and hormone “photoproducts” when our skin is exposed to the UVB wavelength of sunlight (22). These include:

  • β-Endorphin: a natural opiate that induces relaxation and increases pain tolerance (23, 24)
  • Calcitonin Gene-Related Peptide: a vasodilator that protects against hypertension, vascular inflammation, and oxidative stress (25)
  • Substance P: a neuropeptide that promotes blood flow and regulates the immune system in response to acute stressors (26)
  • Adrenocorticotropic Hormone: a polypeptide hormone that controls cortisol release by the adrenal glands, thus regulating the immune system and inflammation (27)
  • Melanocyte-Stimulating Hormone: a polypeptide hormone that reduces appetite, increases libido, and is also responsible for increased skin pigmentation (27)

Exposure to the UVA wavelength of sunlight has also been shown to have benefits, including increasing the release of nitric oxide from storage (28). Nitric oxide is a potent cellular signaling molecule that dilates the blood vessels and thus reduces blood pressure (29).

In addition to the production of photoproducts and release of nitric oxide, sunlight also entrains circadian rhythms. Exposure to bright light during the day activates neurons in the suprachiasmatic nucleus of the hypothalamus, which sends signals to the pineal gland that regulate melatonin production. Disruption of circadian rhythm has been associated with mood disorders, cognitive deficits, and metabolic syndrome (30, 31).

Vitamin D Optimal Levels

Optimal Vitamin D Range Depends on Many Factors

So how much do you need? At the first annual IHH-UCSF Paleo Symposium in San Francisco this year, nutritional biochemist Dr. Chris Masterjohn summarized evidence suggesting that optimal vitamin D levels may vary from population to population, despite the fact that there is currently only one reference range used for all patients.

Ethnicity is one major consideration. For example, black people have lower 25(OH)D than white people in the U.S., yet they typically have much higher bone mineral density. Furthermore, non-Caucasians have lower 25(OH)D levels than Caucasians, even at their ancestral latitudes (32). From these and other studies, it has been suggested that people with non-white ancestry may be adapted to a lower optimal 25(OH)D level than people with white ancestry.

Another factor that influences toxicity is nutritional status. The fat-soluble vitamins A, D, and K work synergistically, and adequate vitamin A and K may protect against toxic effects of excess vitamin D (33). Sufficient levels of potassium and magnesium have also been suggested to protect against vitamin D toxicity (34). Unfortunately, most people have nutrient deficiencies in these micronutrients in the developed world, making them more susceptible to vitamin D toxicity.

What about optimal vitamin D range from an evolutionary perspective? A study on traditionally living hunter–gatherer populations in East Africa found that the Masai and Hadzabe tribes had average 25(OH)D concentrations of 48 ng/mL and 44 ng/mL, respectively (35). These indigenous populations get a great deal of sun exposure but also have very high intakes of vitamins A and K, suggesting that these levels are probably towards the higher end of the optimal range for most people in the modern world.

Using Parathyroid Hormone Levels to Individualize Vitamin D Testing

As we saw in the last section, 25(OH)D lab ranges should vary by population, genetics, and nutritional status. In the absence of specific ranges, we need other biological markers that can help to clarify vitamin D status. To find these biological markers, we need to look at how vitamin D is metabolized.

When UVB contacts the skin epidermis, vitamin D is produced from 7-dehydrocholesterol. This vitamin D then travels in the blood to the liver, where it undergoes primary hydroxylation (the addition of a hydroxyl group, consisting of one oxygen and one hydrogen atom) on the 25th carbon atom. The result is 25(OH)D, which is the metabolite most widely used to assess nutritional vitamin D status. This compound circulates in the blood until it undergoes secondary hydroxylation on the first carbon atom in the kidney, resulting in 1,25(OH)2D, the active form of vitamin D (36).

You might be wondering: why don’t we test the active form? While certainly informative, the amount of active vitamin D is not directly reflective of nutritional vitamin D status because the secondary hydroxylation step is tightly regulated by parathyroid hormone (37). When the parathyroid glands sense a drop of blood calcium levels, they secrete parathyroid hormone (PTH). PTH stimulates the formation of active vitamin D, which increases calcium absorption in the small intestine and calcium release from bone in an attempt to restore normal blood calcium levels (38).

High PTH levels can therefore lead to high 1,25(OH)2D, low bone mineral density, increased risk of fractures, and osteoporosis (39).

With a basic understanding of this pathway, we can use PTH, calcium, and active vitamin D3 as markers to give us a more complete picture of someone’s vitamin D status. In his presentation at IHH-UCSF, Dr. Masterjohn suggested that serum PTH levels above 30 pg/mL may be indicative of biological vitamin D deficiency when 25(OH)D levels are borderline low. Conversely, if 25(OH)D levels are borderline low or even slightly below the laboratory reference range (e.g., 25 to 30 ng/mL), but PTH is less than 30 pg/mL, it is unlikely that the patient is vitamin D deficient, and supplementation is not warranted.

Instead of focusing on the 25(OH)D level itself, what we really want to achieve is maximum suppression of PTH levels for optimal calcium homeostasis and bone health. Beyond this level, more vitamin D is not necessarily better.


Based on my assessment of the literature and my own clinical experience, I believe the functional range for 25(OH)D is around 35 to 60 ng/mL. However, I can’t stress enough that there is significant variation among populations. For those with non-white ancestry, the optimal range may be a bit lower. For those with autoimmune disease, the optimal range might be a bit higher (45 to 60 ng/mL) to maximize the immune-regulating benefits of vitamin D. Here are a few recommendations for optimizing your vitamin D level.

  1. Don’t supplement blindly.
    If your 25(OH)D level is:
  • less than 20 ng/mL: you likely need some combination of UV exposure, cod liver oil, and a vitamin D supplement
  • 20 to 35 ng/mL: get your PTH tested. If PTH is adequately suppressed (less than 30 pg/mL), supplementing is probably unnecessary.
  • 35 to 50 ng/mL: continue your current diet and lifestyle for maintaining adequate vitamin D
  • greater than 50 ng/mL: try reducing your vitamin D supplements, and make sure you are getting adequate amounts of the other fat-soluble vitamins to protect against toxicity
  1. Get retested!
    Check your levels after three to four months to see if you have achieved or maintained adequate levels of vitamin D. If not, adjust your diet, lifestyle, or supplements accordingly and check again in another three to four months.
  1. Get sunlight or UV exposure as your primary form of vitamin D.
    Reap the many benefits of sunlight beyond just subcutaneous production of vitamin D, and reduce your chance of achieving toxic levels. Spend about 15 to 30 minutes, or about half the time it takes your skin to turn pink, in direct sunlight. Sunscreens not only block production of vitamin D, but also all of the other beneficial photoproducts produced in the skin in response to UVB.
  2. Mind your micronutrients to protect against toxicity.
    Try cod liver oil as a good source of vitamins A and D and high-vitamin butter oil or pastured butter and ghee for vitamin K. Sweet potatoes, bananas, plantains, and avocados all contain significant amounts of potassium. Consider supplementing with magnesium as it is very difficult to get adequate amounts of this micronutrient from food due to soil depletion.

Research Spotlight: Health Coaching and Nutrient Deficiencies

Web-Based Nutrition Intervention Improves Nutrient Biomarkers

In-person coaching approaches have demonstrated efficacy for improving patient health and motivation for change in previous clinical trials. However, one-on-one coaching sessions are financially unrealistic for many people. Until recently, it was uncertain whether these interventions could be administered on a large scale and still produce health benefits. A 2018 study assessed the effects of a web-based intervention on health biomarkers, including several markers for common nutrient deficiencies.

Study Summary

  • A longitudinal analysis of blood biomarker data was conducted on samples from 1,032 “apparently healthy” individuals using an automated, web-based nutrition and lifestyle program called InsideTracker.
  • Blood samples were taken at baseline and post-intervention to identify biomarker changes and to correlate these changes to nutrition and lifestyle intervention choices.
  • The duration of the intervention varied widely, with participants engaging in the program for anywhere from three months to 60 months. The intervention recommendations generated for each individual by the web-based program were synthesized from a broad scientific literature base of interventions associated with changes in biomarker levels. For example, an individual with high cholesterol may have been advised to increase oatmeal consumption.
  • Throughout the study, biomarkers showed a trend toward normalcy in participants who were out of range at baseline. Participants with baseline deficiencies in vitamin D and low levels of ferritin, a biomarker for iron status, experienced significant improvements in these markers post-intervention, indicating a normalization of vitamin D and iron deficiencies.

Key Findings

This research indicates that an online health coaching platform is useful for promoting diet and lifestyle behaviors that restore healthy vitamin D and iron status in deficient individuals. These findings suggest that personalized nutrition can be made more accessible through web-based health coaching programs that serve a large group of people.

While this study used an automated system to deliver appropriate interventions to subjects based on their respective biomarkers, a health coach could interact with clients on a more supportive, empowering level, along with the invaluable “human aspect” that is absent in fully automated coaching programs.

A weakness of this study was that it did not require retesting of biomarkers at specific intervals. Very long intervals between baseline and post-baseline testing may have confounded some of the improvements in biomarkers observed with the web-based program. Online, large-scale health coaching programs should incorporate retesting at specified intervals to optimize the efficacy of the coaching intervention. 

Reference:Longitudinal analysis of biomarker data from a personalized nutrition platform in healthy subjects”

The primary job of a health coach is not to act as a nutrition and lifestyle expert. However, having insight into core Functional Health topics—like nutrient density and nutrient status—can help coaches better integrate into a collaborative healthcare environment and relate to what their clients are experiencing. That’s why the ADAPT Health Coach Training Program includes comprehensive, evidence-backed information on Functional Health and ancestral lifestyle and nutrition. Is a future as a Functional Health coach right for you?


Join the conversation

  1. I live in Chicago and get tested every 3 months. (I’m in treatment for chronic Lyme by a docror practicing functional medicine.) My vitamin D levels are creeping up and the latest is 28 in mid-summer. There is also a strong family history of severe osteoporosis (mom, grandma). I supplement with 10,000 IU of D/K2 and take magnesium citrate every evening as well.

  2. I was told by an MD that it’s almost impossible to overdose with vitamin D3. That may or may not be true, but I did find that 6,000 IU of D3 (recommended by a naturopath) is not enough for me. I went from 72 ng/ml to 25 ng/ml in a little less than two years. I’ve since increased my D3 supplementation to 10,000 IU. Some people need to take more vitamin D than others. A lot depends on your age, health, physical condition, genetic makeup, and how much regular sunshine you get. It isn’t a one-size-fits-all type of thing.

    • Did you read Chris’ recommendations?
      Specifically in your case:
      – 20 to 35 ng/mL: get your PTH tested. If PTH is adequately suppressed (less than 30 pg/mL), supplementing is probably unnecessary.

      Might be worth considering. I think an important emphasis here is that serum D levels aren’t the complete store.

    • The Vitamin D counsel recommends to take 1000IU of D for every pound of body weight at the first sign of cold/flu and to do this every day for 3 days regardless of your current Vitamin D status. So, I’ve literally taken fistfuls of capsules all at once with no ill effects. I’ve done it for years. I supplement magnesium and potassium to counter the spike in blood calcium it gives me. I believe it is my duty to check my vitamin D levels occasionally not my doctors… he does the test when I ask. Doctors have literally no education in nutrition so you just might find with an hour of research you know more about Vitamin D than your doctor ever will.

  3. In 2012 I had a malignant melanoma removed from my upper back. My birth mother also had a melanoma removed. I have become sun averse….what are your thoughts about me getting most of my Vitamin D from the sun? thank you

    • Sharon, I keep reading that while basal cell carcinoma can be triggered by excess sun exposure (that is sun burn), melanoma appears to be suppressed slightly by reasonable sun exposure (the sort of exposure that Chris Kresser is suggesting).

      I suggest that you might want to do a little research on that yourself.

      • Thanks, Bill. This was for sure not basal cell carcinoma. I had been through a lot of stress/anxiety and that could sure have contributed to it….but I also worked in the sun a lot – worked at garden centres for many years, ran a school garden program with inner city kids for years….always bending over and looking down. A mole on the top of my back where the sun hit it relentlessly is the one that turned into melanoma. I am not hella worried about it at this point.

    • Hi Sharon,
      Yes, do some research. Malignant melanoma usually occurs on areas of the body *not* sun-exposed. Sun and high Vitamin D reduces melanoma risk and mortality. If you are seriously concerned about cancer, take optimum seleniun and iodine, and go low-carb… eliminate sugar (cancer food!), and grains, particularly wheat.

  4. After being diagnosed with a vitamin D deficiency in 2009 (and avoiding the sun like a plague) I turned to sunlight for my source of vitamin D – I also take Magnesium, potassium, Vitamin K2 (in M4 and M7, primarily M7) and recently broke a bone. I was diagnosed with osteoporosis and my vitamin D levels at 27. This comes in June when I had spent an hour sunbathing each day (that there was sunshine, which was a lot) since March. Ideas? Clearly, I’m not getting it from the sun or my body is not actually getting it, whether the sun is hitting me or not.

    • My board certified nutritionist recommended RX Vitamins Liqui-D3. After an initial loading phase, I now take two drops per day (4000 i.u.) which brought my Vitamin D level to 80 (living in a sunny climate). At a drop or two per day, the bottle may last a year or so.

      After reading this article, however, I may go to one drop.

  5. – My health is adversely affected by Medicare’s denial of payment for repeat laboratory testing of Vitamin D, for which LabCorp then charges about $240.00.
    – Adding to that damaging situation is the fact that NYS (of which I am a resident) does not permit any of the most effective functional medicine tests to be ordered by the very medical practitioners they licensed to practice, even if the patient pays out of pocket.
    – Last year I travelled repeatedly to Connecticut to a functional medicine doctor whose high fees, added to the high cost of the testing, took many thousands of dollars out of my single income retirement savings.
    – Any workable suggestions are most appreciated!

    • Can you eat sardines? If you eat 3-4 cans of sardines per week, you will get plenty of Vitamin D.

    • Join life extension foundation. reasonable blood tests, 1/2 price sales on them every spring. If you join for75 per year they will send requisition thru computer for a local lab to test you. Then they will email you the results. And you can call them and discuss anything on the blood test, or take it to your physician. They are very knowledgeable people. Always on top of new research.

    • Regina,

      You can purchase in-home vitamin D3 test kits from the Vitamin D Council at Individual kits are $50 each, a box of 4 kits is $180. They use a finger stick method that is easy to do. I’ve used their kits several times, service is quite fast and results were available about a week after the blood samples were sent in.

    • I know NYS doesn’t allow Direct Labs to operate there, but does a neighboring state? I get my vit D tests done via Direct Labs because it only costs about $40 (at least it was a year ago).

      • That’s a ridiculous charge for the test. It costs our laboratory about $2 to run the test. Adding on the $10 phlebotomy charge means our lab charges $18 plus $10 which is $28.

          • What happened with our lab was they changed the method to spectometry which is a lot cheaper to run but I think the customers were comfortable with the old price so nothing changed. G.P.’s like to chant how expensive the Vit D testing is so it must have been even more expensive at some stage. Certainly the active form testing (1,25) is horrendously expensive at $400!

  6. Interesting as I just heard a talk with Sanjiv Chopra MD who I guess is well regarded Harvard med school and liver doctor talking about importance of increasing Vit D and he takes 4000iu….not sure what IU levels correspobd to the measurements you talk of. Your posts are usually quite technical for me but interesting perspective.

  7. I heard Chris mention on his podcast that sufficient levels of K2 would guard against vitamin D toxicity, so I started supplementing with Metagenics D3 10,000 IU with 90 mcg of K2 included. I take it daily outside of the summer months, when I usually skip 1-2 days between doses. I haven’t tested levels in a while, but was under the impression the inclusion of K2 in D3 supplements was for the aforementioned reason.

    • Yes Regis, but remember that both vitamin A (actual retenol) and D show toxic effects when the intake of one greatly exceeds that of the other. Many of the processes that both vitamins are involved in require the presence of vitamin K. So adding vitamin K alone when your vitamin A intake is too low can still result in vitamin D toxicity.

      • I think it’s much more unlikely to become toxic than many people fear. You can learn about this from Dr. Zarfraz Zaidis book The Power of Vitamin D3. He has been using d3 in his practice for 20 years and says he has seen many people self supplementing from 8,000 to 15,000 iu daily for years but has never seen anyone toxic based on the kinds of criteria and testing another commenter talked about regarding the high doses used for MS. He said he’s only ever seen high calcium in a handful of people and only with prolonged dosages much higher than this like 30,000 iu and up. Even in these cases that was reversed by lowering calcium intake. And this was without taking A, K2, magnesium etc. which are best to take as well. His recommended conservative dosage for people who don’t want to test is 1,000 iu per 25 pounds of body weight. He said that in his experience people don’t experience the full benefits with less than that.

  8. I take 1,000 units of D a day as prescribed by my doc. My vitamin D levels were low before and I do feel better so to speak while on it. I do get in the sun some but mostly the end of the day. Should I stop my D altogether. I suspect now it maybe raising my blood pressure….

    • Vitamin D acts like a steroid, so many people with autoimmune disease and/or stealth infections do feel better while taking it, but it can still be very harmful longterm, just as steroid would be.

  9. Vitamin D Success Story

    Tell us a little bit about yourself:

    My name is Ana Claudia. I’m 46 years old and I live in Albuquerque, New Mexico.

    How did you hear about GrassrootsHealth?

    I found the GrassrootsHealth page through vitamin D articles on Facebook.

    How was your health before using vitamin D?

    In the beginning of 2008 I was diagnosed with multiple sclerosis (MS). I was very sick when I heard about a treatment being prescribed in my home country, Brazil, which involved high doses of vitamin D. I heard about this from an old friend who also had MS and had already been on the treatment for 4 years with excellent results. At the time I did a lot of research on it and decided to try it, so I made an appointment, went to Brazil and started my treatment.

    How much vitamin D do you take? Do you go out in the sun?

    I take 50,000 IU a day and also enjoy the sun whenever possible. I have been on this treatment for 7 years now and have had no further problems with MS. No flare ups, new lesions or disease progression, as shown in my MRIs.

    What is your vitamin D blood level?

    My levels are high but I don’t know exactly how high because the lab only lists >160 ng/ml. The high levels of vitamin D are not considered a problem, the calcium is the problem. I follow a diet with no dairy, and every 6 months have a round of blood and urine tests for calcium levels, liver, kidney and thyroid function, etc. All my test results in these 7 years of treatment have been great. Before I started the treatment my D level was about 42 ng/ml.

    What would you recommend to others who are in a similar situation?

    I’d recommend that they research about this option; in my opinion it sure beats all the conventional treatments for MS that are out there.

    There is a Facebook group about this treatment; it’s in Portuguese, but there are patients from all over the world there and posts in many different languages.

    How do you tell others about vitamin D?

    I try to share my experience whenever I can; I’m also an active member of many social network groups.

    Thank you for sharing your story, Ana. We wish you further good health!

    Note: GrassrootsHealth does not currently have any data to support any additional health benefit of having a vitamin D blood level of 100 ng/ml or above. The recommended serum level range, per our Scientists’ Call to Action, is 40-60 ng/ml (100-150 nmol/L) for best overall health.

    It is important to note that vitamin D related toxicity has been observed at levels of 200 ng/ml (500 nmol/L) and higher per J. Hathcock, Am J. Clin Nutr. 2007;85:6-18.

  10. Dear sir, please please read the works of Morley Robbins, he is so against anyD supplementation,he say it is number 1 suppresser of the protein produced in the liver to bind iron,,,
    please would love to know your thoughts on this subject,,,,
    thanks a lot

    • Morley Robbins is a pompous arse who doesn’t understand any of the nonsense he preaches. No wonder he censors those who expose all the hurt he does to people. Please do yourself a huge favor and look for another person with a God complex to worship.

  11. Do you have a safe recommendation for cod liver oil? I’ve taken Blue Ice Royal Butter/Cod liver oil but have read recently that the source/reliability of the oil is in question. I’ve read it’s not safe to take. Have you any thoughts on this?

    • Check the site. I think that you will find that Green Pasture was a victim of an unjustified attack. Indeed the very Dr. Masterjohn that Chris mentioned above is just one of those that weighed in on what they felt was a completely unethical attack on the company.

      • I have been taking Dr. Mercola’s krill oil, which he says is acquired from a place that does not have any toxins. He says it’s one of the few (maybe only?) fish oils that can be assured that it isn’t toxic or rancid.

    • The FCLO story is controversial. You can read more than you ever wanted to know from Dr. Kaayla Daniels (formerly VP of WAPF), David Gumpert, Dr. Ron Schmid, and others. Dr. Daniels broke the story with her “Hook, Line and Stinker” e-booklet.

  12. I think adults use 3000IU – 4000IU per day. Did I read that on the Vit D Council website? …. I think so. Anyhow I only supplement from May – October here in Australia myself. The rest of the year I rely on our strong sunshine. I’ve had blood levels done each year and I go low at the end of Summer so the 4000IU I take per day see me through Winter and the time when I’m not actively in the sun. Come October I cease the D3 drops. This seems to work for my health, skin type and AI conditions. This protocol keeps me at a level of 100-110 (range 50-150).

  13. Hi!

    Unfortunately, you did not link negative Symptoms due to high levels of Vitamin D to the absence of Vitamin K2 and Magnesium. Those three work hand in hand. If there is not enough K2 present, elevated D levels might cause problems and if not enough Magnesium is present, same applies, but for different reasons. Please update your article with some proper sources for this topic, as it lacks now the most important facts about Vitamin D supplementation (as most online sources do….. but usually, your homepage is one of the best, so do not let this article stay as it is, kind of a a black sheep).



  14. I live in Scandinavia and it’s practically impossible to get almost any amount at sunlight during larger parts of the year, but even now in the summertime. In such a case, is vitamin D deficiency most likely? I’ve never tested. But if one supplements most of the year, does it make any sense to stop taking supplements on sunny days?

  15. Do you have a good suggestion for affordable testing for those of us whose insurance doesn’t cover the cost of testing?

    • Search an independent MD who is “off the grid” so to speak. He does not take insurance of any kind and negotiates good prices for labs. This has worked for me.

    • Both the Vitamin D Council and Grassroots Health offer very affordable, do-it-yourself test kits. No doctor involved.

    • Check to see if Direct Labs operates in your state (assuming you’re from the US). You order the test online, bring the order to one of their approved labs, and get the results by email. Very affordable.

  16. One well-known doctor advises against spending time in the sun IF one has autoimmune disease (I have Hashimoto’s). My mother-in-law had lupus and was advised by her doctor to avoid being in the sun.
    What is your opinion on direct sunlight for those with autoimmune disease?

    • News on Hashimoto! It is caused by fluoride longterm intoxication ! Fluor agregates in thyroid cells And attracts calicium in those cells. This combined for 10-15 years make autoimmunosation, so hashimoto is probably not idiopathic as believed for years! But has a reason! It is difficult to clean The body off fluoride. The Best And only studied way is physical excercise And TAURINE suplementation after. Excercise sweaps fluoride from tissues to blood stream And TAURINE thereafter binds it so They can be excreted via urine.

    • Well, psoriasis is an autoimmune disease and one of the most effective treatments is sunlight, so your doctor’s assertion doesn’t make sense. What is their reasoning?

      • I have psoriasis and extreme light sensitivity and have trouble metabolizing active vitamin D1,25 back into the safer storage D25 form. The biggest trigger for my psoriasis is light exposure.

  17. Many experts urge supplementation with magnesium.
    I have neurally mediated hypotension, and when I supplement with magnesium it makes my blood pressure drop even further, making me dizzy and ill.
    Is there any good solution to this?
    I drink water that has been filtered with a very good filter.

    • I suggest you take a red blood cell (RBC magnesium) test. Its similar to the A1C test for blood glucose. It gives you an average of magnesium in your cells over a about a 90 day period. Maybe you don’t need magnesium but calcium?

  18. I really wish there was some type of home testing for Vitamin D levels. It becomes very difficult to always having to go to the doctor to be tested. With the change of seasons here in Michigan, I really do not know how much “D” to take without taking too much or not enough. I did find that my “D” levels only went up when I was taking 10,000 IU.

  19. I have seen some empirical reports on individuals who were extremely deficient in Vitamin D who had severe adult periodontitis. Do you have any information on this connection?

    • I would also like to find out if there is any information on the link between low Vit. D and adult periodontal disease.

      • I am a periodontist and there are no scientific studies on Vitamin D and periodontal disease. However, I have seen several anecdotal articles indicating there is a connection, primarily when the Vitamin D level is extremely low

          Effects of vitamin D status on oral health
          Hypovitaminosis D status usually reflects reduced sunlight exposure.

          Inadequate sunlight exposure accelerates oral diseases by reducing vitamin D activity.

          Reduced vitamin D levels may increase the incidence of periodontal diseases.

          Helpful effect of vitamin D on oral health may be related to anti-inflammatory effect.

          Vitamin D may stimulate the production of anti-microbial peptides in the oral cavity.

          • Yes, these are studies on the relationship of Vitamin D and periodontal/oral disease, but if you read them with any care you will see the word MAY in many places…These are not on any solid scientific ground

    • Get your levels tested and base your supplementation those readings. Mine went from 75 mmol to 120 mmol (note different units) when I supp’d with 5000 units so I decided to bite them in half and get twice the usage for a level that is now 100 mmol. This is in the right place

    • Where in OZ?, below parallel 34 (just around Sydney and below) you do not create any Vit D in the skin in winter, and what you have created in the body from the sun in summer will go in half in 2 months (same if you are a sailor in a submarine and go down for 8 weeks), here in Melbourne our dose for the 6-8 months of winter (we are in spring but still like winter where it is the sun?) with 5000iu and go up to 6/7000iu in the middle of winter, we are now in 4000iu and we continue all summer in 4000iu unless we go out and enjoy the sun and in that day we reduce the dose, we are nearly 70 years old both never one medication or sick, we checked the last few years our Vit D level and it is around 125 mmol/L (50ng/mL) [in the first week of September mi wife had 124 (49.7) and myself 128 (51.3)] it is in the middle of the optimal chart above. At the end of summer we check again to see the levels, and they are always in the 12x mmol/L. By the way all in the family do the same 3 are Pharmacists, one a GP’s and Endocrinologist in the San Vincent Hospital, when you know your end of winter and summer levels use the calculator in the right here and get the right dose to be around 125 mmol/l (50 ng/mL in the US)