> When in doubt, get a blood test. Definitely. I would say get one regularly anyway, Vitamin D levels are important enough that they should be part of routine

> When in doubt, get a blood test. Definitely. I would say get one regularly anyway, Vitamin D levels are important enough that they should be part of routine blood work done during a regular physical. Then, if you're supplementing, you can adjust your dosage accordingly based on the results so your blood levels stay in the desired range.