Summary of dosing suggestions

  • From birth to childhood and even adolescence, the American Academy of Pediatrics recommends at least 400IU of vitamin D per day.

  • The current recommendation from The Canadian Cancer Society is at least 1000IU of Vitamin D per day to help raise levels within adults. However, most experts actually consider 2000IU of Vitamin D per day as correct amounts. This is especially true for people who are older, pregnant, dark skinned, or obese.

  • To make sure you are at your right leves, research has concluded that it is best to take Vitamin D3 5000 IU per day for a three month period and then get a 25-hydroxyvitamin D test. The goal is to adjust your vitamin d dosage so that your blood levels are between 50-80 ng/mL year round. (Press Release)

It is best to starting taking Vitamin D3 supplements and after several months getting tested for the right dosage. Most people living in Northern areas of the world are not at best intake levels and actually closer to absolute deficiency. After several months you can then gage where you are at and make the necessary dosing modifications.

When choosing the right vitamin D supplements, there are several forms to consider and the correct one to take when increasing your levels is Vitamin D3. Unfortunately the only form of vitamin D available by prescription in the USA and UK is ergocalciferol. This is an artificial form of Vitamin D that isn’t quite as effective as Vitamin D3 in raising your levels. Vitamin D3 is available over the counter in the USA and over the internet. However beware that not all of varieties of Vitamin D are Vitamin D3. One of the most common mistakes is to take cod liver oil. A lot of commercial supplies can contain high levels of Vitamin A which can essentially cancel out the effects of Vitamin D. Therefore make sure you aren’t going with a supplement that contains both Vitamin A and D.

The Canadian Cancer Society is the first time an institution has recommended taking at least 1000IU of Vitamin D3 per day. This was in conjunction of evidence that these dietary supplements can influence the risks of cancer. However, many studies have concluded that 1000IU of Vitamin D3 isn’t enough to help bring up one’s levels to point of cancer prevention. There has been research that has concluded 2000IU is ideal, but even that has been turned away due to not reaching optimal levels.
Dr. Heaney at the Creighton University Medical Center recommends that adults should take 5000IU of Vitamin D3 to achieve optimal levels. This has been later modified to recommending 5000IU per day in the fall and winter and 2000Iu per day for summer and spring as you are exposed to more sunlight. Either way, please consult with your physician and get your vitamin D levels measured for a more accurate recommendation.


What Blood level of vitamin D is Optimal?

Optimal levels of Vitamin D have been researched by looking at people who work out doors or in very sunny part of the world. Sunlight can’t produce toxic levels of Vitamin D because the body will start to get rid of any excess amounts. For this reason, the average vitamin D level for people who are in constant contact with the sun is 50-70ng/ml range which is considered optimal.
Vitamin D deficiency is classified when your levels start to get below 15ng/ml. Epidemiological studies have shown that levels between 33-52ng/ml is the right range to achieve reduction in the more common forms of cancer. In today’s research, most experts agree that one’s vitamin d levels should be greater than 50ng/ml.


The Safety of High Dose Vitamin D

It’s not 100% clear yet if high doses of Vitamin D are safe for you. The United States position is that one should take around 2000IU of Vitamin D per day. The UK is a bit more conservative and suggests around 1000IU per day. However, studies have shown that 4000IU and even 10,000Iu per day of vitamin d is safe.

A recent study in nursing homes gave patients 5000IU every day. After a year, not adverse events were distinguished. Plasma levels did increase from an average of 11.4ng/ml to 50ng/ml. Multiple Sclerosis also have a strong link between Vitamin D deficiency and their conditions and thus have often are treated with 6000IU of vitamin d per day.

Safety of doses up to 40,000IU per day to patients suffering from Multiple Sclerosis (MS). (143)

In this study 12 patients with MS were given weekly doses of Vitamin D3 and the dose escalated every few weeks. The table below shows the dosing regimen:

Study WeekDose of D3/IU/week
1-2        0
3-4     28000
5-10   56000
11-16 112000
17-22 224000
23-28 280000

The highest dose given equates to 40,000IU of Vitamin D3 per day. None of the patients developed hypercalcemia and no adverse events were seen in any patient throughout the 28 week trial. The mean serum Vitamin D levels at the start of the study was 31ngs/ml and at completion of the trial were 154ngs/ml.

While this publication showed the results of the first 28 weeks of therapy it has been reported that the study continued for twelve months and no adverse effects were seen. NO ONE SHOULD CONCIDER TAKING DOSES THIS HIGH UNLESS UNDER MEDICAL SUPERVISION. THESE RESULTS ARE PRESENTED HERE TO UPDATE YOU ON THE LATEST MEDICAL RESEARCH AND PERHAPS REASSURE THAT DOSES OF 1000-2000IU PER DAY IS UNLIKELY TO PRODUCE ADVERSE EFFECTS.

The products and the claims made about specific products on this site have not been evaluated by the United States Food and Drug Administration and are not intended to diagnose, treat, cure or prevent disease. The information provided on this site is for informational purposes only and is not intended as a substitute for advice from your physician or other health care professional. You should consult with a healthcare professional before starting any diet, exercise or supplementation program, before taking any medication, or if you have or suspect you might have a health problem





The products and the claims made about specific products on this site have not been evaluated by the United States Food and Drug Administration and are not intended to diagnose, treat, cure or prevent disease. The information provided on this site is for informational purposes only and is not intended as a substitute for advice from your physician or other health care professional. You should consult with a healthcare professional before starting any diet, exercise or supplementation program, before taking any medication, or if you have or suspect you might have a health problem.
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