40 ng response to 4,000 IU daily Vitamin D for 2 months (and 60 ng for 8,000 IU) – Jan 2025

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Comparison of Vitamin D3 Supplementation Doses of 1,000, 2,000, 4,000 and 8,000 IU in Young Healthy Individuals

In Vivo. 2025 Jan-Feb;39(1):452-458. doi: 10.21873/invivo.13848.
Marketa Kralova 1, Michal Jirasko 1 2, Eva Dedeckova 1, Hedvika Hatakova 1 2, Pavel Broz 3, Vaclav Simanek 2, David Slouka 4, Ladislav Pecen 5, Radek Kucera 1 2

Background/aim: Low levels of vitamin D are a widespread global issue. This study aimed to determine the optimal vitamin D3 supplementation dose for healthy young adults by comparing the effectiveness of gradually increasing cholecalciferol doses over two years.

Patients and methods: Thirty-five volunteers participated in a two-season pilot study conducted from October to April to avoid sunlight-induced vitamin D3 synthesis. The participants used oil-based drops of cholecalciferol, increasing their dose from 1,000 to 2,000, 4,000, and then 8,000 IU daily for 60 days with a 30-day break.

Results: Supplementing with 1,000 IU/day raised vitamin D levels to the recommended range (above 75 nmol/l), but levels dropped below this range after a 30-day break. A dose of 2,000 IU/day maintained vitamin D levels within the recommended range, even after the break. Increasing the dose to 4,000 IU/day produced a rapid rise, though levels dropped more significantly after stopping supplementation. With 8,000 IU/day, both the rise and subsequent decline in vitamin D levels were more pronounced.

Conclusion: Effective vitamin D supplementation in healthy young adults can be achieved with a daily dose of 2,000 IU during winter. However, 4,000 IU/day was more effective for maintaining levels above 100 nmol/l, supporting broader health benefits. Regular monitoring of 25(OH)D, calcium, and phosphorus levels is essential.
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VitaminDWiki - 4,000 IU of Vitamin D daily is safe, but takes a year to plateau (Best-D) – RCT Dec 2016

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VitaminDWiki - 4,000 IU of Vitamin D - many pages (110 pages as of Jan 2025)

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VitaminDWiki - 4,000 IU of Vitamin D is OK - 19 organizations agree - 2018

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VitaminDWiki - Response to Vitamin D - many studies

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VitaminDWiki – Loading doses are used to speed up the response

207 items in category
see also Overview Loading of vitamin D   Overview Toxicity of vitamin D
Better than Daily 1: Fewer chances to forget, 2) Gets past receptor barrier
Injection category has 65 items
 
It appears that over 1 million Vitamin D loading doses have been taken
Doses ranged from 100,000 to 600,000 IU over a period of a day to a month
No reports of serious adverse reactions
Many studies report on the benefits resulting from loading doses

TOP articles in Loading Dose of Vitamin D

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VitaminDWiki – Optimum category contains

The RDA (600 IU is barely enough for bones of infants.
   Need an optimal level for the body to thrive

99 items in Optimum Vitamin D category

Example pages

• Is 50 ng of vitamin D too high, just right, or not enough
• Revisiting Vitamin D Guidelines – Holick Oct 2024 has
  
• Saudi study defines normal Vitamin D level to be 50 to 70 ng (diabetes, etc.) - June 2020
• Need 40 to 60 ng of Vitamin D – 48 scientists call for action – 2015
• Vitamin D RDA of 600 IU is not enough - global RCT meta-analysis March 2019
• Vitamin D sufficiency 10 to 30 ng, optimal 40 to 80 ng (no consensus)– May 2018
• 4 X fewer visits to Dr. after getting high level of vitamin D (Interview with transcript) - Jan 3, 2022
• Vitamin D sufficiency 10 to 30 ng, optimal 40 to 80 ng (no consensus)– May 2018
• Sports benefits from up to 50 ng of Vitamin – meta-analysis - Nov 2012
• Vitamin D of 32 to 60 ng is needed before, during, and after pregnancy – Dec 2012
• Hypothesis by VitaminDWiki – Vitamin D levels are no longer limited by evolution
• VitaminDWiki pages with HIGH-DOSE in title 878 as of Nov 2024