Vitamin D3 and K2: how to read the label
verdavita editorial team · 2026-11-05
Check the daily amount of vitamin D against the NIH upper limit, look for the form of vitamin K, and talk to your doctor first if you take warfarin.
Do the math for a full day
The label amount is per serving. If the directions say to take it twice a day, double the number. The NIH upper limit for vitamin D for adults is 100 mcg (4,000 IU) a day, and that counts every source you take.
Many labels list both units, so compare mcg with mcg. For example, Sun D3 lists 50 mcg (2,000 IU) per softgel.
Vitamin K forms
K1 is phylloquinone. K2 is a group called menaquinones, and the NIH names MK-4, MK-7 and MK-9 as the most studied. The NIH lists Adequate Intakes of 90 to 120 mcg a day for adults.
Warfarin
Warfarin and some other anticoagulants work against vitamin K, so the NIH says people taking them need to keep vitamin K intake consistent. Talk to your doctor before starting a product with vitamin K.
Vitamin D supplements can also interact with medications.
Products mentioned
Sources
- NIH Office of Dietary Supplements: Vitamin D fact sheet for health professionals
- NIH Office of Dietary Supplements: Vitamin K fact sheet for health professionals
General information, not medical advice. Images are illustrative.