If a person is, or is suspected to be, very vitamin D deficient a loading dose is typically given
- Loading = repletion = quick replacement (previously known as Stoss)
- Loading doses range in size from 100,000 IU to 1,000,000 IU of Vitamin D3
- The size of the loading dose is a function of body weight - see below
Unfortunately some doctors persist in using Vitamin D2 instead of D3, which has been shown to have many problems
- Loading may be done as quickly as a single day, to as slowly as 3 months.
It appears that spreading the loading dose over 4-20 days is a good compromise - not too fast, not too slow.
- Loading is typically oral, but sometimes by injection (I.M,)
- The loading dose persists in the body for about 3 months
The loading dose should be followed up with continuing maintenance - typically 4,000 to 10,000 IU daily average
Unfortunately many doctors fail to follow-up with the maintenance dosing.
- As about 1 in 300 people have some form of mild allergic reaction to vitamin D supplements,
it appears prudent to test with a small amount of the exact form of vitamin D before giving a loading dose
Causes for a mild allergic reaction appear to be: (in order of occurance)
1) lack of magnesium - which can be easily added
2) allergy to capsule contents - oil (powder does not appear to cause any reaction)
3) allergy to the tiny amount of D3 itself (allergy to wool) ( alternate: D3 made from plants )
Cholecalciferol loading dose guideline for vitamin D-deficient adults.
Eur J Endocrinol. 2010 Apr;162(4):805-11. Epub 2010 Feb 5.
CONCLUSION: The cholecalciferol loading dose required to reach the serum 25-OHD(3) target level of 75 nmol/l can be calculated as follows:
dose (IU)=40x(75 - serum 25-OHD(3))xbody weight.
CLICK HERE for PDF of the study and equation
Equation converted into units of ng and pounds
Dose to get 30 ng (in ng and pounds) = 35 x (30 - serum 25-OHD(3)) x body weight.
Typically spread over over 8 weeks
A very commonly prescribed loading dose in the US is 50,000 IU per week for 8 weeks, for a total of 400,000 IU
Example uses of the equation to achieve 30 ng (on average)
|Dose|| starting |
|140,000 IU||10 ng||200 lb|
|70,000 IU||20 ng||200 lb|
|105,000 IU||10 ng||150 lb|
Dose to get 50 ng (in ng and pounds) = 35 x (50 - serum 25-OHD(3)) x body weight.
Example uses of the equation to achieve 50 ng (on average)
|Dose|| starting |
|280,000 IU||10 ng||200 lb|
|210,000 IU||20 ng||200 lb|
There is a HUGE variation in response between individuals for the average (equation)
Fastest response time for a loading dose
- 600000 IU dose raised youth vitamin D level by 60 ng in 3 days – July 2010 60 ng 16 ng ==> 77 ng
See also at VitaminDWiki
- All Megadose vitamin D items 52 items
- Large single dose of more than 300,000 IU of vitamin D works well for 3 months – Review Nov 2013
- 300,000 IU loading dose of vitamin D stopped gestational diabetes in RCT – Oct 2011
- 300,000 IU vitamin D helped seniors in many ways – May 2011
- Vitamin D3 loading dose of 500,000 IU for elderly – Aug 2009
- Loading dose of 500,000 IU for elderly - Whiting 2010 PDF file
- 540000 IU before ICU raised vitamin D by 25 ng in 2 days – March 2011 25 ng
- Will lots of vitamin D help in ICU – RCT Nov 2012 540,000 loading dose
- Single 600,000 IU dose raised youth vitamin D level by 60 ng in just 3 days – July 2010
- 600,000 IU vitamin D normalized virtually all seniors in 3 months – May 2012
- Variety of vitamin D loading dose recommendations in the UK
- Can You Overdose on Vitamin D - It's Harder Than You Think
- Doctors now able to prescribe vitamin D3 as of March 2012
- Many reasons why vitamin D deficiency has become epidemic
- Must balance co-factors when increasing vitamin D
- Vitamin D Replentishment – Feb 2012 Plotnikoff
- Overview Rare Allergic reaction to vitamin D about 1 in 300 people
- Huge gap between vitamin D advice and actual prescriptions – April 2012
only 1.4% of those with < 10 nanograms of vitamin D got any loading dose
- Overview Toxicity of vitamin D >2,000,000 every day for a week is toxic
- Guideline following hip fracture – 50000 IU vitamin D daily for 7 days – Jan 2013
daily, with no testing needed, 40 ng: 12 ng ==> 52 ng ( 350,000 IU, measured on day 14)
- Review of Vitamin D (including free, frequency, injection, how much.) – Sept 2013
See also web
- Superiority of a High Loading Dose of Cholecalciferol to Correct Hypovitaminosis D in Patients with Inflammatory/Autoimmune Rheumatic Diseases. Dec 2012
300,000 IU much better than 100,000 IU for rheumatic diseases
- Can one or two high doses of oral vitamin D3 correct insufficiency in a non-supplemented rheumatologic population? Feb 2013
one or two oral bolus of 300,000 IU of vitamin D3 can correct vitamin D insufficiency in 50% of patients.
only tested patients who had 10 - 30 ng levels at the start