THORNE Vitamin D3 Supplement, 1,000 IU, 180 Capsules for Bone & Immune Support

THORNE Vitamin D-1,000 is a vitamin D3 supplement designed to support bone and teeth health, immune function, and cardiovascular health, with a 1,000 IU strength and 180 capsules.

• Vitamin D3 as cholecalciferol — supports calcium absorption for healthy bones and teeth.
• Immune and cardiovascular support — provides vitamin D for these important body functions.
• Third-party tested and certified — verifies label contents and checks for unsafe contaminant levels.
• 180 capsules — provides a multi-capsule supply of vitamin D3.
• Made with vitamin D3 rather than D2 — research shows D3 is more effective at raising overall vitamin D levels.
• Relevant for limited sun exposure — addresses vitamin D needs when indoor routines or low sun exposure limit natural production.

Vitamin D is needed for the body’s natural functions, but time spent indoors or inadequate sun exposure can limit the sunlight that supports its production. THORNE Vitamin D-1,000 provides vitamin D3 in capsule form for adults seeking support for calcium absorption, bones and teeth, immune function, and cardiovascular health.

What does THORNE Vitamin D-1,000 support?

Vitamin D3 supports calcium absorption, which contributes to healthy teeth and bones, as well as immune function and cardiovascular health. Vitamin D also supports performance, muscle strength and mass, and cellular repair, particularly for people who work indoors or get limited sun exposure.

• Vitamin D3 is provided as cholecalciferol.
• The formula is intended to support the body’s natural vitamin D needs when sun exposure is limited.

How does this vitamin D3 differ from vitamin D2?

THORNE Vitamin D-1,000 uses cholecalciferol, the D3 form of vitamin D. Vitamin D3 is more potent and better absorbed than vitamin D2, also known as ergocalciferol; research also finds D3 more effective at increasing overall vitamin D levels.

• Vitamin D3 form: cholecalciferol.
• Vitamin D2 form: ergocalciferol.

How is THORNE Vitamin D-1,000 tested?

This supplement is third-party tested and certified to confirm that the contents match the label and that the product contains no unsafe levels of contaminants. THORNE is trusted by more than 100 professional sports teams. In a 2026 independent survey of U.S. supplement consumers and health-care practitioners, THORNE was the most recommended clinical brand.

• Third-party verification covers label accuracy and contaminant levels.
• The recommendation ranking is based on the stated 2026 U.S. survey.

THORNE Vitamin D-1,000 is suited to people looking for vitamin D3 support for bone and teeth health, immune and cardiovascular function, or those whose indoor routine limits sun exposure. Its 1,000 IU strength, capsule format, and third-party certification make it a clearly specified option for that purpose.

Ingredients

One Capsule Contains: Vitamin D (as Cholecalciferol) (D3) 25 mcg (1,000 IU). Other Ingredients: Microcrystalline Cellulose, Hypromellose (derived from cellulose) capsule, Leucine, Silicon Dioxide, Vitamin E Succinate.