Vitamin D

The sunshine vitamin, essential for absorbing calcium and building bone.

Also known as: Ergocalciferol, Cholecalciferol, Calcitriol
Evidence: Established nutrient Evidence level 5 of 5
Body systems: Liver, Nerves, Bones, Vitality and immunity

In research

Vitamin D is converted in the liver and kidneys into calcitriol, its active hormone form, which controls calcium absorption from the gut.

Strength of evidence

Established nutrient

An essential nutrient with well defined roles and recommended intakes. How we grade evidence.

What we know

Essential for calcium absorption. Correcting deficiency matters, but supplementing people who are not deficient did not reduce fractures in a large trial.

What we do not know yet

The ideal blood level for different people and its role beyond bone.

Safety and cautions

Excess can raise blood calcium, causing nausea, thirst and kidney problems. Calcitriol, the active form, should be used only under medical supervision with monitoring.

Evidence

Research and answers

Appraised research and plain-language answers that involve Vitamin D.

Randomised controlled trial No clear effect

Vitamin D3 and fractures in generally healthy adults (VITAL)

Supplements help most when they correct a shortfall. Testing and targeting are wiser than assuming everyone benefits.

New England Journal of Medicine, 2022 · 25,871 participants · Vitamin D

QuestionBones

Do I need a vitamin D supplement?

Only if you are low, or at risk of being low. A very large trial found that giving vitamin D to generally healthy adults who were not deficient did not reduce fractures.

Myth or evidence

If a little is good, more must be better

Usually not. For most nutrients and medicines, benefit levels off once a need is met, while side effects keep rising.

Myth or evidenceBones

Calcium alone builds strong bones

Calcium is the raw material, but bone strength depends on much more: vitamin D to absorb it, vitamin K2 and protein to build it into bone, hormones and, above all, weight-bearing activity that tells bone to grow stronger.

Where you will find it

Products that contain it

Ceptomin A complete daily nutritional foundation. Film-coated tablet · 15 mcg

Heptocept Considered nutritional support for the liver. Tablet · 400 IU

Ceptonerv Targeted nutrition for nerve health. Tablet · 400 IU Ceptomin-KO Calcium, with the partners it needs. Tablet · 0.25 mcg

Often found alongside

The full atlas

Aloe veraAloe barbadensis Alpha lipoic acidNutrient AmlaEmblica officinalis ArjunaTerminalia arjuna AshwagandhaWithania somnifera BiotinVitamin

Ingredient pages summarise traditional use and the direction of published research for education. They are not claims about any product and are not medical advice.

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