Vitamin D: What It Is, Forms, Cautions, and Clean Brands

Vitamin D is the sunshine vitamin. It supports bone health and immune function.*

Forms and what to look for on the label

D3 is the most common form, and it’s often paired with K2. It absorbs best with a meal that has fat.

Before you take it

It’s possible to take too much. A blood test can help you find the right dose.

What independent doctors say

Dr. Peter McCullough says what he uses in his practice in a Dec 24, 2024 post on The Focal Points:

“In clinical practice I recommend 10,000 IU of vitamin D with 100-200 mcg of vitamin K2” (The Focal Points, Dec 24, 2024)

Dr. Andrew Huberman described his own routine in a May 2, 2022 episode. He said he takes “5,000 IUs” of vitamin D3 a day and added, “I’ve had my levels tested and they’re in range.” (Huberman Lab, May 2, 2022)

A Midwestern Doctor talks about vitamin D alongside sunlight in an Oct 29, 2026 Substack post:

“Vitamin D supplementation can be very beneficial, but in almost all cases, raising your vitamin D through appropriate sunlight exposure provides significantly greater benefits.” (A Midwestern Doctor, Oct 29, 2026)