Kirkland Signature Extra Strength D3 50 mcg., 600 SoftgelsED. 01 2028 Kirkland Signature Extra Strength D3 50 mcg., 600 Softgels Kirkland Signature Vitamin D3 2000 IU supports healthy bones, teeth, and muscles as well as a healthy immune system. Kirkland Signature D3, the bodys preferred form of Vitamin D, is a great way to ensure you are getting enough of this essential micronutrient to support overall health. Features Helps support bone, teeth, muscle and immune health Helps improve Calcium absorption in