Vitamin D3

Vitamin D3 (Cholecalciferol) is a fat-soluble secosteroid and essential hormone synthesized via skin UV-B exposure or dietary sources. In research contexts, high-dose D3 is provided in injection form (20000 IU/ml).

D3 is the active biological precursor to 1,25-dihydroxyvitamin D3 (Calcitriol), the hormonally active metabolite that controls calcium regulation, bone metabolism, and immune function.

This information is for research and educational purposes only. No medical advice.

Vitamin D3 is hydroxylated in the liver to 25-hydroxyvitamin D [25(OH)D], the primary storage and circulating form. In the kidney, it is then hydroxylated to the active hormone 1,25-dihydroxyvitamin D3 (Calcitriol), which:

• Regulates intestinal absorption of calcium and phosphate
• Modulates bone remodeling through parathyroid hormone signaling
• Signals immune cell function via vitamin D receptor (VDR)
• Supports muscle protein synthesis and myocyte function

Extensive literature supports vitamin D's role in:

• Bone metabolism and osteoporosis prevention
• Muscle strength and cardiac function
• Immune cell function and infection resistance
• Calcium homeostasis and parathyroid hormone regulation

Studies show vitamin D deficiency is associated with bone loss, muscle strength decline, increased infection risk, and cardiovascular problems. Injected D3 is used in research to examine optimal serum concentrations.

• Vitamin D toxicity: Acute toxicity is rare at moderate doses; chronic high-dose can lead to hypercalcemia (rare)
• Local irritation: Pain or swelling at injection site (mild, rare)
• Hypersensitivity: Very rare
• Systemic: Nausea, appetite loss, headache (only with toxicity, not therapeutic doses)
• Monitoring: Serum calcium and vitamin D levels should be monitored in long-term research protocols

Store cool and dry, protected from light (ideally 2-8°C). Keep vial in original carton. Use within 8 weeks of opening. Do not freeze. Visually inspect for cloudiness or particles before use.