One issue here I'm realizing is in a difference of assumptions... I'm used to taking vitamin D3 drops under my tongue, which I imagine absorb differently than

One issue here I'm realizing is in a difference of assumptions... I'm used to taking vitamin D3 drops under my tongue, which I imagine absorb differently than capsules. But even so, fat soluble substances can get into the blood pretty quickly when you ingest them, well within the timespan of one day. So I'm not sure if I understand your reasoning. Can you link to a source? Something I'm reading now that sounds similar to what you're saying is that during supplementation, it takes a while for serum vitamin D levels to reach a steady state. Maybe that's what you're referring to? Edit: check this out https://www.sciencedirect.com/topics/medicine-and-dentistry/vitamin-d https://www.sciencedirect.com/topics/medicine-and-dentistry/... > After an oral dose of vitamin D, blood levels begin to rise at 4 hours, peak by 12 hours, and return to close to baseline by 72 hours. In this article, I take "baseline" to refer to what I called "steady state" earlier in this comment.