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Endocrinology

Vitamin D Deficiency

Vitamin D deficiency is a common condition that can cause muscle and bone pain, fatigue, and disorders of calcium and bone metabolism.

ℹWhat is Vitamin D Deficiency?

Vitamin D is less a vitamin than a potent prohormone. It plays a critical role in almost every area of human physiology, from the regulation of calcium and phosphate metabolism and the support of the immune system to bone mineralisation and muscle function. A large part of the body's vitamin D is synthesised when sunlight reaches the skin, and the rest comes from food.

Because of modern living conditions, long periods spent indoors, sunscreen use and geographical factors, vitamin D deficiency is common in the general population. At eKonsey, our Multidisciplinary Council of experienced physicians in endocrinology, metabolic diseases and nutritional medicine takes a holistic approach to resistant vitamin D deficiency, malabsorption and its hormonal consequences.

Advantages of the eKonsey Multidisciplinary Approach

  • Comprehensive Laboratory Analysis: Vitamin D levels need to be interpreted together with calcium, phosphate, PTH and ALP.
  • Resolving Resistant Cases: In cases that do not respond to standard treatment, the underlying malabsorption or metabolic block is identified.
  • Reliable Second Opinion: Your test results are reviewed by expert professors wherever you live, and a Medical Opinion is prepared for you.

Common Symptoms

Muscle and bone pain
Widespread muscle and bone pain.
Chronic fatigue and weakness
Persistent tiredness, weakness and low energy.
Muscle weakness
Muscle weakness felt when climbing stairs or standing up.
Hair loss
Hair loss and brittle nails.
Reduced immunity
Frequent illness and reduced resistance to infection.

Causes

Chronic and Resistant Vitamin D Deficiency
Blood 25-OH vitamin D levels remain below the reference range for a long time. When levels fail to rise despite standard supplementation, underlying metabolic or genetic factors need to be investigated.
Secondary Hyperparathyroidism due to Vitamin D Deficiency
Long-standing vitamin D deficiency and the resulting fall in calcium absorption make the parathyroid glands overwork to keep blood calcium balanced (secondary hyperparathyroidism). Over time this can accelerate mineral loss from the bones.
Malabsorption
Digestive disorders (coeliac disease, Crohn's disease, irritable bowel syndrome), a history of bariatric surgery, or liver or kidney dysfunction can prevent vitamin D from being absorbed from the gut or converted to its active form.

Second opinion for Vitamin D Deficiency

A second specialist's review of your Vitamin D Deficiency diagnosis or treatment plan can clarify your next step. On eKonsey this review is done online.

When is a second opinion useful?

  • When the diagnosis is unclear or more than one possibility was discussed
  • When surgery or a long-term treatment was recommended
  • When the response to treatment is not what you expected

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Frequently Asked Questions

Last updated: October 15, 2026

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