What are the effects of Vitamin D (Cholecalciferol) toxicity?

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Last updated: March 12, 2025View editorial policy

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From the Guidelines

Vitamin D toxicity is a rare but potential harm of treatment with oral vitamin D, which may lead to hypercalcemia, hyperphosphatemia, suppressed parathyroid hormone, and hypercalciuria, typically occurring at 25-(OH)D levels above 200 ng/mL 1. The effects of Vitamin D (Cholecalciferol) toxicity can be severe and include:

  • Hypercalcemia
  • Hyperphosphatemia
  • Suppressed parathyroid hormone
  • Hypercalciuria
  • Kidney problems
  • Bone pain
  • Calcium deposits in soft tissues It is essential to note that toxicity generally requires taking more than 10,000 IU daily for months, with blood levels exceeding 150 ng/mL. To avoid toxicity, adults should not exceed 4,000 IU daily without medical supervision, and if toxicity is suspected, immediately stop vitamin D supplements and seek medical attention. Treatment involves discontinuing vitamin D, reducing calcium intake, increasing fluid intake, and possibly medications like bisphosphonates or corticosteroids in severe cases, as reported in the study published in the Annals of Internal Medicine 1. Recovery typically occurs within weeks to months after stopping excessive intake. Most people can safely maintain vitamin D levels through a combination of limited sun exposure, dietary sources like fatty fish and fortified foods, and moderate supplementation of 600-2,000 IU daily as recommended by healthcare providers based on individual needs and blood levels. It is crucial to be aware of the potential harms of treatment with oral vitamin D and to follow the recommended guidelines to avoid toxicity, as emphasized in the study 1.

From the Research

Effects of Vitamin D Toxicity

The effects of Vitamin D (Cholecalciferol) toxicity can be severe and include:

  • Hypercalcemia, which can lead to adverse effects on cardiac, central nervous system, renal, and gastrointestinal functions 2, 3, 4, 5, 6
  • Nausea, vomiting, altered sensorium, constipation, pancreatitis, acute kidney injury, and weight loss 3, 4, 5
  • Increased bone resorption, which can be treated with bisphosphonates such as pamidronate 6
  • Elevated serum 25-hydroxyvitamin D levels, which can be used to diagnose vitamin D intoxication 2, 3, 4, 5

Risk Factors for Vitamin D Toxicity

Risk factors for vitamin D toxicity include:

  • Overdose of vitamin D caused by prescription of mega-doses of vitamin D 3
  • Irrational use of vitamin D in mega-doses 3
  • Consumption of contaminated foods or manufacturing errors of vitamin D-containing supplements 5
  • Use of dietary supplements that may contain high levels of vitamin D, even if not claimed on the label 5

Treatment of Vitamin D Toxicity

Treatment of vitamin D toxicity typically involves:

  • Discontinuation of vitamin D intake 2, 4
  • A diet with low calcium and phosphorus content 2
  • Intravenous hydration with saline 2, 5
  • Loop diuretics, glucocorticoids, calcitonin, and bisphosphonates may also be used to treat hypercalcemia and other symptoms 2, 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Vitamin D intoxication.

The Turkish journal of pediatrics, 2012

Research

How Much Vitamin D is Too Much? A Case Report and Review of the Literature.

Endocrine, metabolic & immune disorders drug targets, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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