Natural Factors Vitamin D3 1000 IU 180 Tablets

Vitamin D3 is the form of vitamin D naturally produced by the body through sunlight exposure. It supports calcium absorption, healthy bones and teeth, muscle function, and immune health. Vitamin D3 is also most effective when paired with vitamin K2, which helps direct absorbed calcium into bones instead of soft tissues.

If you're building a stack focused on immune resilience, bone strength, healthy calcium metabolism, and maximizing the benefits of vitamin K2, this is a supplement that may be worth exploring.