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Vitamin D3 (Cholecalsiferol)

Having enough vitamin D is important for a number of reasons, including maintaining healthy bones and teeth; it may also protect against a range of conditions such as cancer, type 1 diabetes, and multiple sclerosis.

Supporting research & information

Despite the name, vitamin D is considered a pro-hormone and not actually a vitamin.

Vitamins are nutrients that cannot be created by the body and therefore must be taken in through our diet. However, vitamin D can be synthesized by our body when sunlight hits our skin.

It is estimated that sensible sun exposure on bare skin for 5-10 minutes 2-3 times per week allows most people to produce sufficient vitamin D, but vitamin D breaks down quite quickly, meaning that stores can run low, especially in winter.

Vitamin D is used for preventing and treating rickets, a disease that is caused by not having enough vitamin D (vitamin D deficiency). Vitamin D is also used for treating weak bones (osteoporosis), bone pain (osteomalacia), bone loss in people with a condition called hyperparathyroidism, and an inherited disease (osteogenesis imperfecta) in which the bones are especially brittle and easily broken. It is also used for preventing falls and fractures in people at risk for osteoporosis, and preventing low calcium and bone loss (renal osteodystrophy) in people with kidney failure.

Vitamin D is used for conditions of the heart and blood vessels, including high blood pressure and high cholesterol. It is also used for diabetes, obesity, muscle weakness, multiple sclerosis, rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), asthma, bronchitis, premenstrual syndrome (PMS), and tooth and gum disease.


Vitamin D3 is the common name for cholecalciferol.

Vitamin D3 can be taken as a supplement to improve overall health or used to treat osteoporosis.

It can also be used to treat conditions in which vitamin D3 levels may be low, such as in people who have underactive parathyroid glands, low levels of phosphate in the blood, or hereditary conditions in which the body doesn't respond to the parathyroid hormone.

Vitamin D3 also encourages the kidneys to recycle phosphate back into the blood, which helps the blood stay at the right pH.

Vitamin D3 is available for purchase over-the-counter (OTC).

Vitamin D3 Deficiency

Historically, vitamin D3 loss has been associated with rickets, a disease caused by low levels of vitamin D3 that commonly affects children.

Children with rickets and adults who had rickets as children often have legs that are bow-shaped.

However, while adults who are deficient in vitamin D3 do not typically develop rickets disease, their bones may start to become softer — a condition known as osteomalacia.

People with digestive problems like celiac disease, liver problems, or Crohn's disease are more likely to have low levels vitamin D3.

Sunlight is a natural source of vitamin D3, and people who rarely or never go outside (for example, those in nursing homes or bedridden hospital patients) are most likely to be deficient in it.

Also, the darker your skin, the more sunlight you need to keep vitamin D3 at healthy levels.

This is because the extra melanin found in darker skin slows the absorption of vitamin D3.

Some studies suggest that the time of day when you receive sunlight affects how well your body absorbs vitamin D3.

While many experts advise people to avoid sunlight between the hours of 10 AM and 2 PM or 3 PM to help protect their skin from cancer, data shows the body actually absorbs vitamin D3 better during this time.

The Difference Between Vitamin D2 and Vitamin D3

There are two forms of vitamin D: Vitamin D2, or ergocalciferol, is commonly found in foods.

Vitamin D3 is made by the body naturally when skin is exposed to the sun.

Although there is some debate, most experts currently believe that the best form of vitamin D supplement to take is vitamin D3.

It's thought that D3 is more natural and easier for the body to absorb.

Also, the body does not allow as large a concentration of D3 to circulate in the bloodstream as it does D2, so it's considered safer.

35+ Proven Health Benefits of Vitamin D (Part 1)

Vitamin D is a fat-soluble vitamin that is naturally present in very few foods. It helps fight against cancer, improves physical performance, prevents osteoporosis, helps promote brain function and reduces depression. Deficiency of this vitamin may lead to brain disorders like Parkinson’s and Alzheimer’s.

Vitamin D, also known as the “sunshine vitamin”, is an essential fat-soluble vitamin. 

It can either be obtained in the diet, through food and dietary supplements, or synthesized in the skin upon exposure to sunlight (R).

Although classified as a vitamin, it should be considered a prohormonebecause it is involved in many metabolic processes in the body (R, R2).

Vitamin D plays a role in calcium and phosphorus balance important in bone health, and nerve and muscle activity.

It also regulates blood pressure, immune function, cell production, and insulin secretion.

It plays a potential role in prevention and therapy of cancer and chronic conditions such as autoimmune disorders, cardiovascular disease, and infections.

Vitamin D Can Improve Physical Performance

Clinical evidence suggests that vitamin D plays a role in muscle metabolism and function.

Hence the function of the muscle is either of an indirect nature or does not involve the known receptor.

Supplementation with this vitamin has been shown to improve muscle strength, balance, and physical performance.

It reduces falls in diverse settings including adolescents, the elderly, and chronic kidney disease patients.

Supplementation also reduced the risk of falls by more than 20%.

Vitamin D may increase muscle strength by improving atrophy of type II muscle fibers, which may lead to decreased falls and hip fractures.

Insufficiency of this vitamin is associated with increased fat infiltration in the muscles of healthy young women.

It may improve athletic performance in vitamin D-deficient athletes.

This vitamin deficiency appears to be correlated with increased risk of illness and injury among athletes, especially in regards to stress fractures.

Vitamin D is Beneficial for Brain Development and Function
Vitamin D is considered as a hormone active in the brain (neurosteroid).

The vitamin D receptor (VDR) and the enzyme responsible for the synthesis of the active form of this vitamin are present in the brain.

Studies indicate that this vitamin is important for brain development.

And its deficiency is associated with a wide range of psychiatric and neurological diseases.

It may protect brain cells through detoxification pathways (production of antioxidant glutathione, inhibition of nitric oxide). 

Furthermore, it also helps synthesis of proteins necessary for survival of brain cells in aging and neurological diseases (neurotrophins).

Epidemiological studies show that low concentrations of vitamin D are associated with:

  • impairments in cognitive functions such as memory and orientation
  • diagnosis of dementia and Alzheimer’s disease
  • higher rates of psychotic experiences and schizophrenia
  • depressive symptoms

 Vitamin D Improves Cognitive Functions
Studies suggest that low levels of blood vitamin D are associated with low mood, impaired cognitive functions, and dementia. While, other studies suggest that blood levels of this vitamin do not influence cognitive or emotional functioning. Supplementation of 5000 IU/daily of this vitamin for 6 weeks did not have beneficial effects on memory, depression, anxiety or anger.

Vitamin D Reduces Depression
Deficiency of vitamin D was associated with an 8–14% increase in the prevalence of depression and a 50% increase in suicide rates. Supplementation may reduce depressive symptoms, and improve physical functioning in patients with depression. Also, some studies showed that supplementation of this vitamin neither worsened nor improved depressive symptoms. In elderly postmenopausal women, there was no effect of hormone therapy and vitamin D either individually or in combination on depression.

Vitamin D Improves Sleep Quality
Vitamin D could be important for sleep disorders. Higher concentrations of this vitamin were associated with better maintenance of sleep. In National Health and Nutrition Examination Survey (NHANES) study, lower vitamin levels were associated with shorter sleep duration. Some studies suggest improved sleep quality with vitamin D supplementation. It has been hypothesized that its deficiency is central to a recent ‘epidemic’ of disturbed sleep patterns. Studies have reported a high prevalence of this vitamin deficiency in obstructive sleep apnea syndrome. This is a widespread disorder characterized by episodes of breathing cessation due to upper airway tract obstruction during sleep. Its deficiency is more pronounced in severe sleep apnea and associated with abnormal glucose production. More studies are needed to prove this relationship between sleep quality and vitamin D supplementation.

Further Reading


Contained in

This ingredient is found in the following Eudeamon products


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