Vape pen is an ideal route for your body to absorb CBD quickly and efficiently. I am quoting an article from leafy.com which explains in more detail: https://www.leafly.com/news/health/vaping-cbd-oil-vs-ingesting
"During vaporization, CBD enters your lungs and diffuses directly into your bloodstream rather than passing through your gut and liver. This avoids the first-pass effect altogether, allowing nearly four times as much CBD to enter your circulation for a maximum bioavailability of roughly 50 to 60 percent. Essentially, this means you can achieve the same beneficial effects with a much smaller amount of CBD."