What's Rhonda Patrick's guidance on Vitamin D supplementation?

Rhonda Patrick’s guidance is to take vitamin D3 according to measured blood levels; she says she takes 5,000 IU daily, which keeps her level around 50 ng/mL. 1

• 5,000 IU and her level: Patrick reports taking 5,000 IU of vitamin D3 daily and says her blood level hovers around 50 ng/mL. 1
• Test before and after: She recommends measuring levels before and after supplementation. For most people without relevant SNPs, she estimates 1,000 IU raises blood levels by about 5 ng/mL; individual needs can differ. 2 3
• Safety and upper limit: Patrick says hypercalcemia is extremely difficult to develop, describing concern at hundreds of thousands of IU daily for a long time. She notes the Institute of Medicine set the upper tolerable intake at 4,000 IU; she personally takes 5,000 IU. 4
• SNPs and dose needs: Common genetic variants can make vitamin D conversion less efficient, so the dose that raises blood levels may vary; testing is how to determine the response. 2