We Asked a Pharmacist If You Should Always Take Vitamin D and K2 Together

Verywell Health • February 23, 2026 • health

Key Points:

Taking vitamin D and vitamin K2 together is optional and not required, as there are no official guidelines recommending their combined use in the U.S.
Vitamin D supports calcium absorption and bone health, while vitamin K2 activates proteins that help direct calcium into bones and prevent its deposition in arteries, though clinical evidence confirming their combined benefit is lacking.
The concern that taking vitamin D without K2 might cause calcium to deposit in the wrong places remains theoretical and unproven by clinical trials.
Both vitamins are generally safe to take together, but vitamin K2 can interact with certain medications like blood thinners, and excessive vitamin D intake may lead to hypercalcemia, so consulting a healthcare professional before supplementation is advised.