Cholecalciferol

Studies in people

• Open question

  Vitamin D levels in the blood²

  Cholecalciferol raised vitamin D levels in the blood more than another form of vitamin D did.

• Open question

  Vitamin D blood levels³

  Vitamin D3 raises blood levels of vitamin D more than vitamin D2 does, especially in people with a lower BMI.

• Benefit

  Hip fracture risk⁴

  In older people, daily vitamin D3 with calcium lowered hip fracture risk, though bone density did not change.

• Benefit

  Bone and muscle health⁵

  A review found cholecalciferol has more scientific evidence with positive results than calcifediol for musculoskeletal diseases.

• Open question

  Child brain development⁶

  In people, mothers with higher vitamin D levels had children with lower autism and ADHD risk, but cholecalciferol supplements made no difference.

• Benefit

  Vitamin D deficiency⁷

  Vitamin D3 supplements helped patients in this hospital, and no bad reactions were seen even at high doses.

• No harm found

  Frailty in older adults⁸

  In older people, taking cholecalciferol (vitamin D3) did not change frailty scores over five years.

• Benefit

  Gut inflammation in people⁹

  In people with gut inflammation, cholecalciferol helps balance the immune signals that drive it.

• No harm found

  Artery stiffness¹⁰

  Taking cholecalciferol did not improve artery stiffness in adults across seven studies.

• Open question

  Bone and heart health¹¹

  Cholecalciferol may help bones and the heart, but big trials give mixed results, so scientists do not yet know for sure.

• No harm found

  Blood pressure¹²

  Cholecalciferol (vitamin D3) supplements showed no overall effect on blood pressure, though results varied by dose, duration and group.

• Benefit

  COVID-19 hospital stays¹³

  COVID-19 patients with low cholecalciferol were hospitalized more often, and those given cholecalciferol went home about 5 days sooner.

• Benefit

  Multiple sclerosis inflammation¹⁴

  In people with MS, taking cholecalciferol for 8 weeks lowered a marker of inflammation and oxidative stress.

• Open question

  Liver disease and vitamin D¹⁵

  In people with long-term liver disease, cholecalciferol supplements raised both vitamin D and a related compound in the blood.

• Benefit

  Vitamin D levels in kidney disease¹⁶

  In people with kidney disease, weekly cholecalciferol raised vitamin D levels, though the best level is still debated.

Study type not stated

• No harm found

  Hormone-related health effects¹⁷

  Scientists found no published evidence that cholecalciferol disrupts hormones, though it is made in skin from sunlight.

• Benefit

  Sunlight and calcium¹⁸

  Cholecalciferol is vitamin D3, which your body makes from sunlight and which helps you absorb calcium.

How it’s made and used

• Vitamin D supplements¹⁹

  In lab studies, cholecalciferol films broke down in under a minute and released at least 75% of the vitamin in 15 minutes.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.