02/26/2026
Cold and flu season isn’t over.
One simple thing you can do to protect yourself?
Get your vitamin D levels into the optimal range.👏
We’re still in winter, with less sun ☀️ exposure, which means your body is likely producing far less vitamin D3.
And that can directly impact your immune resilience during a time when you need it most.
👉First step: ask your doctor to check your levels.
In functional medicine, we typically aim for a 25(OH)D level between 50–80 ng/mL for optimal immune and overall health.
While 30 ng/mL may be considered “normal,” it’s sub-optimal.
Also important: check the form you are taking.
Vitamin D2 is the form commonly prescribed and added to fortified foods because it’s cheaper and more stable in processing.
But research shows it’s less effective at raising and maintaining blood levels, and may even lower circulating D3 in some cases.
Vitamin D3 is the form your body naturally makes from sunlight and is more effective at supporting optimal levels.
And if your levels are still low despite supplementing?
There may be underlying factors affecting absorption and activation, see slides.👆
Before increasing your dose, check your levels and make sure you’re using the right form❣️
Comment BLOG, and I’ll send you the link to learn more.
Dr. Ann