Diseases

Vitamin D3 (25OH)

Vitamin D3 (Cholecalciferol) is the most important member of the group of fat-soluble D vitamins, which are crucial for calcium balance, bone mineralization, and tooth and hair formation. The body can obtain Vitamin D3 both through diet (primarily from fatty fish) and by synthesizing it with the help of sunlight.

The significance of Vitamin D3 25OH for health

Vitamin D3 25OH, also known as Calcidiol, plays a central role in human organism health. This biomarker is produced in the liver from the precursor vitamin D3 (Cholecalciferol) and is a reliable indicator of the vitamin D status in the bloodstream. Measuring this value is crucial as an optimal vitamin D level is essential for numerous physiological processes.

A balanced vitamin D level not only supports the regulation of calcium and phosphate metabolism, crucial for bone health, but also has extensive effects on the immune system, muscle and nerve function, and the regulation of inflammatory processes in the body. Furthermore, prolonged vitamin D deficiency can lead to serious conditions such as depression, cancer, cardiovascular diseases (e.g., heart attack, stroke), respiratory diseases (asthma), metabolic disorders (e.g., type 2 diabetes), and autoimmune diseases (e.g., multiple sclerosis).

Measuring the Vitamin D3 25OH level allows for the timely detection of potential deficiencies or excesses and the implementation of appropriate measures to optimize health. An individually tailored approach to vitamin D supplementation may be recommended based on these laboratory results to achieve an optimal vitamin D status and support long-term good health.

Further informations

Vitamin D3 (25OH)

Fat-soluble vitamin


  • Regulation of calcium and phosphate metabolism
  • Essential for bone health as it supports the absorption of calcium and phosphate from the intestine
  • Has far-reaching effects on the immune system, muscle and nerve function, as well as the regulation of inflammatory processes in the body

A deficiency in Vitamin D3 25OH can lead to a variety of health problems, including:

Bone Health:

  • Rickets in children: Disruption of bone mineralization, accompanied by bone pain and deformities. 
  • Osteomalacia in adults: Weakening and softening of the bones, accompanied by bone pain and deformities. 

Neuromuscular Symptoms:

  • Muscle weakness 
  • Muscle pain 
  • Joint pain 
  • Neuromuscular hyperexcitability (tetany) 
  • Muscle cramps 

Other Symptoms:

  • Hair loss 
  • Increased susceptibility to infections 
  • Paresthesia (such as of the lips and fingers) 
  • Migraines

An overdose of Vitamin D3 can lead to hypervitaminosis.

Symptoms:

  • Nausea 
  • Vomiting 
  • Constipation 
  • Weakness 
  • Weight loss 
  • Irregular heartbeat 
  • Calcification of blood vessels and other soft tissues 

Excessive intake of Vitamin D3 is not achievable naturally through food!

The primary source of Vitamin D3 is sunlight exposure on the skin. It's also found in certain foods, including fatty fish (such as salmon, mackerel, tuna), liver, egg yolks, and fortified foods.