Vitamins. Regulator of calcium-phosphorus metabolism
ATC code: A11CC05 (Colecalciferol (vitamin D3))
Brand names – drugs
Drisdol
Brand names – supplements
Solgar Vitamin D3, NOW Foods Vitamin D-3, Thorne Vitamin D
Supplements are not tested in clinical trials and are not registered as medications.
Colecalciferol (vitamin D3) is hydroxylated in the liver to 25-hydroxyvitamin D and then in the kidney to the active form 1,25-dihydroxyvitamin D (calcitriol). Calcitriol binds the nuclear vitamin D receptor and regulates intestinal calcium and phosphate absorption, renal calcium reabsorption, and bone mineralisation. It also modulates immune function, cell proliferation, and cytokine synthesis.
Adjunct
A required component of combination therapy for postmenopausal osteoporosis together with calcium and antiresorptive or anabolic agents (bisphosphonates, , teriparatide). and meta-analyses show that combined calcium 1,000–1,200 mg and vitamin D 800–1,000 IU daily reduces hip fracture risk by 16% in at-risk populations. Vitamin D monotherapy in patients with normal bone density does not reduce fracture risk.
Vitamin D monotherapy is not indicated for fracture prevention in pre- or postmenopausal women without osteoporosis.
First line
Cornerstone treatment and prevention of rickets in children. Prophylactic dose for term newborns is 400 IU daily from the first days of life, 800–1,000 IU daily for preterm infants. Therapeutic dose for established rickets is 2,000–5,000 IU daily for 30–45 days followed by prophylactic dosing. Efficacy is supported by decades of paediatric practice and is reflected in the and Russian Paediatric Society guidelines.
In children with concomitant gastrointestinal disease (coeliac disease, cystic fibrosis, short bowel syndrome) doses are individualised with 25(OH)D monitoring.
First line
First-line therapy for correcting vitamin D deficiency and insufficiency in adults. Standard loading regimens are 50,000 IU weekly for 8 weeks or 6,000 IU daily, followed by maintenance 1,500–2,000 IU daily. Target 25(OH)D is at least 30 ng/mL per the Endocrine Society and Russian clinical guidelines. Doses are 2–3 times higher in obesity, malabsorption syndromes, and in patients on anticonvulsants.
In chronic kidney disease colecalciferol is preferred over active metabolites (alfacalcidol, calcitriol) for initial therapy. In sarcoidosis and other granulomatous diseases, only with monitoring of serum calcium.
Individual decision
In adults over 65 with confirmed vitamin D deficiency, 800–1,000 IU daily reduces the risk of falls in several meta-analyses. The 2018 update found the effect insufficient in patients without deficiency and withdrew the prior recommendation. The decision is individualised based on 25(OH)D level, physical activity, and other fall risk factors.
Doses above 4,000 IU daily without clinical indications are not recommended – dedicated RCTs showed a paradoxical increase in fall risk.
Individual decision
The VITAL trial (BMJ 2022) showed a 22% reduction in autoimmune disease incidence in adults 50+ after 5 years of vitamin D 2,000 IU daily. The finding comes from a single cohort, has not been reproduced in other RCTs, and the effect accrues over years. International rheumatology societies do not recommend vitamin D as primary prevention of autoimmune disease.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
The 2021 Cochrane review (46 RCTs, more than 75,000 participants) showed a modest effect on acute respiratory infections – about 2% absolute reduction, more pronounced in patients with baseline deficiency. , , and CDC do not include vitamin D in respiratory infection prophylaxis protocols. Routine prescribing in patients without deficiency is not justified.
Vaccination and hand hygiene remain the cornerstones of respiratory infection prevention.
Not recommended
Cholecalciferol (vitamin D3) is a fat-soluble vitamin. It is prescribed for prevention and treatment of vitamin D deficiency and for osteoporosis in combination with calcium (AEMPS Ficha Técnica). In anti-aging communities, vitamin D3 is taken in high doses to slow aging and extend life. The large VITAL trial (NEJM 2019, over 25,000 participants) showed no reduction in cardiovascular events or all-cause mortality on 2000 IU/day vitamin D3 versus placebo. In people with normal 25(OH)D, no clinical studies of prophylactic anti-aging use exist. Overdose causes hypercalcemia with risk of kidney dysfunction and arrhythmias. If cholecalciferol is being taken in high doses without confirmed deficiency, consider seeking a second opinion.
1 pair found. Sorted from critical to minor.
Mechanism
Vitamin D increases intestinal calcium absorption by activating calbindin in enterocytes. The synergistic effect benefits osteoporosis and calcium deficiency.
Symptoms
On a balanced dose, no symptoms. At excessive doses of vitamin D (over 4000 IU/day chronically) and calcium (over 1500 mg/day), hypercalcaemia risk: thirst, polyuria, nausea, weakness, arrhythmia.
Management
Standard combination in osteoporosis prevention and treatment: colecalciferol 800–2000 IU/day plus calcium 1000–1200 mg/day (counting dietary calcium). Check calcium and creatinine every 6 months in patients with chronic kidney disease or prior nephrolithiasis.
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FDA category A at recommended doses. Prophylactic use in pregnancy and lactation is encouraged. Doses above 4,000 IU daily without 25(OH)D monitoring are not recommended.
Transfers into breast milk in small amounts. On 400–600 IU daily in the mother, the infant receives less than 10% of daily needs – breastfeeding alone does not provide a prophylactic dose, so infants are supplemented directly.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Colecalciferol is evaluated for the following indications with varying evidence strength: Rickets in children (evidence tier A), Postmenopausal osteoporosis (evidence tier A), Vitamin D deficiency (evidence tier A). See the full indication matrix with dosing and citations above on this page.
Common side effects of Colecalciferol (≥ 1 in 100): Dry mouth, Dyspepsia at high doses. See the Safety section for uncommon and serious reactions.
FDA category A. FDA category A at recommended doses. Prophylactic use in pregnancy and lactation is encouraged. Doses above 4,000 IU daily without 25(OH)D monitoring are not recommended.
Transfers into breast milk in small amounts. On 400–600 IU daily in the mother, the infant receives less than 10% of daily needs – breastfeeding alone does not provide a prophylactic dose, so infants are supplemented directly.
Colecalciferol is contraindicated in: Hypercalcaemia of any aetiology; Hypervitaminosis D; Calcium-based renal stones; Active pulmonary tuberculosis; Sarcoidosis and other granulomatous diseases (only with calcium monitoring). Full list in the Safety section.
the recommendation applies to at-risk groups (northern latitudes, older adults, dark skin, anticonvulsants, obesity). Healthy people with normal 25(OH)D do not derive proven benefit.
RCTs have not confirmed effects on cognition, depression, or cancer outcomes (VITAL, Cochrane). Only deficiency correction, rickets, and osteoporosis as adjunctive therapy are high-tier indications.
D3 (colecalciferol) is more effective than D2 (ergocalciferol) per meta-analyses – it raises 25(OH)D faster and more stably.