Mechanism of Action-

Biologically active metabolites of vitamin D occurs in two steps. The first hydroxylation of vitamin D3 cholecalciferol (or D2) occurs in the liver to yield 25-hydroxyvitamin D while the second hydroxylation happens in the kidneys to give 1, 25-dihydroxyvitamin D. These vitamin D metabolites subsequently facilitate the active absorption of calcium and phosphorus in the small intestine, serving to increase serum calcium and phosphate levels sufficiently to allow bone mineralization. Conversely, these vitamin D metabolites also assist in mobilizing calcium and phosphate from bone and likely increase the reabsorption of calcium and perhaps also of phosphate via the renal tubules. There exists a period of 10 to 24 hours between the administration of cholecalciferol and the initiation of its action in the body due to the necessity of synthesis of the active vitamin D metabolites in the liver and kidneys. It is parathyroid hormone that is responsible for the regulation of such metabolism at the level of the kidneys.

Pharmacokinetics-

Cholecalciferol is readily absorbed from the small intestine moreover, bile is necessary for absorption as well. The mean central volume of distribution of cholecalciferol supplementation was approximately 237 L. The protein binding documented for cholecalciferol is 50 to 80%. Specifically, in the plasma, vitamin D3 (from either diet or the skin) is bound to vitamin D-binding protein (DBP) produced in the liver, for transport to the liver. Within the liver, cholecalciferol is hydroxylated to calcifediol (25-hydroxycholecalciferol) by the enzyme vitamin D-25-hydroxylase. At the kidney, calcifediol subsequently serves as a substrate for 1-alpha-hydroxylase, yielding calcitriol (1,25-dihydroxycholecalciferol), the biologically active form of vitamin D3. It has been observed that administered cholecalciferol and its metabolites are excreted primarily in the bile and feces. The half-life of cholecalciferol as being about 50 days.

Common Side effect of this product includes:

The product is possible safe for most adults. There is no disadvantage associated with the product if taken under the recommended usage however chest pain, feeling short of breath, muscle or bone pain, constipation, nausea, and vomiting may occur in some patients.

• High levels of vitamin D in your body 
• High levels of calcium in your blood
• Malabsorption
• Heart disease
• Kidney disease
• Electrolyte imbalance

Carefully use this product in the following conditions:

• Arrhythmia
• Electrolyte imbalance
• Hypercalcemia
• Renal dysfunction
• Hepatobiliary dysfunction