5,000 or 10,000 IU Vitamin D for 7 years both safe and effective (4700 patients, 8 months to plateau) – Jan 2019

Daily oral dosing of vitamin D3 using 5000 TO 50,000 international units a day in long-term hospitalized patients: Insights from a seven year experience.

J Steroid Biochem Mol Biol. 2019 Jan 3. doi: 10.1016/j.jsbmb.2018.12.010.
McCullough PJ1, Lehrer DS2, Amend J3.

  • 1 Dept of Psychiatry, Wright State U.School of Medicine, Dayton, OH, 45435,. Summit Behavioral Healthcare, Cincinnati, OH, 45237, pmccullough1@cinci.rr.com.
  • 2 Dept of Psychiatry, Wright State U School of Medicine, Dayton, OH, 45435; Summit Behavioral Healthcare, Cincinnati, OH, 45237,
  • 3 Summit Behavioral Healthcare, Cincinnati, OH, 45237

Virtually all of the Vitamin D was 5,000 or 10,000 IU of D3
A single patient used 50,000 IU doses of D2 to treat psoriasis

 Download the PDF from Sci-Hub via VitaminDWiki

Response charts



Vitamin D3 is a secosteroid hormone produced in the skin in amounts estimated up to 25,000 international units (IUs) a day by the action of UVB radiation on 7-dehydrocholesterol. Vitamin D deficiency is common due to both lack of adequate sun exposure to the skin, and because vitamin D is present in very few food sources. Deficiency is strongly linked to increased risk for a multitude of diseases, several of which have historically been shown to improve dramatically with either adequate UVB exposure to the skin, or to oral or topical supplementation with vitamin D.
These diseases include asthma, psoriasis, rheumatoid arthritis, rickets and tuberculosis.
All patients in our hospital have been routinely screened on admission for vitamin D deficiency since July 2011, and offered supplementation to either correct or prevent deficiency.
During this time, we have admitted over 4700 patients, the vast majority of whom agreed to supplementation with either 5000 or 10,000 IUs/day.
Due to disease concerns, a few agreed to larger amounts, ranging from 20,000 to 50,000 IUs/day.

There have been no cases of vitamin D3 induced hypercalcemia or any adverse events attributable to vitamin D3 supplementation in any patient.
Three patients with psoriasis showed marked clinical improvement in their skin using 20,000 to 50,000 IUs/day.

Analysis of 777 recently tested patients (new and long-term) not on D3 revealed 28.7% with 25-hydroxyvitaminD3 (25OHD3) blood levels < 20 ng/ml, 64.1% < 30 ng/ml, a mean 25OHD3 level of 27.1 ng/ml, with a range from 4.9 to 74.8 ng/ml.
Analysis of 418 inpatients on D3 long enough to develop 25OHD3 blood levels > 74.4 ng/ml showed a mean 25OHD3 level of 118.9 ng/ml, with a range from 74.4 to 384.8 ng/ml.
The average serum calcium level in these 2 groups was 9.5 (no D3) vs 9.6 (D3), with ranges of 8.4 to 10.7 (no D3) vs 8.6 to 10.7 mg/dl (D3), after excluding patients with other causes of hypercalcemia.
The average intact parathyroid hormone levels were 24.2 pg/ml (D3) vs. 30.2 pg/ml (no D3).

In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs/day appears to be safe.

See also VitaminDWiki

Subsequent analysis of that study - no excess Calcium

Normal 24-hour Urine Calcium Concentrations after Long-term Daily Oral Intake of Vitamin D in Doses Ranging from 5000 to 50,000 International Units in 14 Adult Hospitalized Psychiatric Patients
J Steroid Biochem Mol Biol . 2023 May 12;106329. doi: 10.1016/j.jsbmb.2023.106329
Steven J Repas 1, Benjamin N Schmeusser 1, William P McCullough 2, Douglas S Lehrer 3, Jeffrey B Travers 4, Patrick J McCullough 5

Many controversies exist regarding vitamin D3 supplementation. These include not only diseases that are responsive to vitamin D supplementation, but also the long-term safety of prolonged daily oral vitamin D3 intake above 4000 to 10,000 International Units (IU). In particular, supplementation levels that do not result in adverse events, and the upper limits of safe serum 25-hydroxyvitamin D (25OHD) concentrations. Adverse reactions reported to occur with excessive vitamin D intake include hypercalcemia, renal failure, calcium crystal formation, undetectable parathyroid hormone concentrations, and hypercalciuria, all of which are reported to be reversible. To address the long-term safety of vitamin D supplementation, we previously reported data from patients in our hospital who have been voluntarily supplemented with vitamin D3 ranging from 5,000 to 10,000 IU/day since July 2011 as a standard of care for the prevention and treatment of vitamin D deficiency. Historically 90% of patients have agreed to daily supplementation, with most taking 10,000 IU/day.
These data indicate no evidence for hypercalcemia, renal failure, calcium crystal formation, nephrolithiasis. or undetectable parathyroid hormone concentrations in patients taking 5,000 or 10,000 IU/day for extended periods of time.
As another measure for potential vitamin D toxicity, we retrospectively assessed 24-hour urine calcium excretion in 14 individuals on long-term daily oral vitamin D intake ranging from 5,000 to 50,000 IU/day to further assess the safety of supplementation using these doses. This included patients taking either 5,000 (4), 10,000 (9), or 50,000 (1) IU/day. Time on supplementation ranged from 10 to 102 months. A patient taking 400 IU/day and getting frequent sun exposure was also included.
All fifteen 24-hour urine calcium measurements were normal. The current findings complement our experience with over 7000 patients in the past 13 years, indicating that prolonged daily oral intake of vitamin D3 ranging from 5000 to 10,000 IU/day is safe.

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