Posted by cachecrab 10/28/2025
It is my general understanding that unless you are severely deficient, Vitamin D supplementation generally takes weeks to bring levels up. It's unlikely that taking it for a few days is going to have any measurable impact on your recovery from illness unless you are severely deficient and/or taking MASSIVE doses, which may or may not be recommended depending on your prior levels and BMI.
See more here: https://www.ccjm.org/content/89/3/154
e: fixed broken URL
Uhm, how can you get to that conclusion? I mean: how can you compare the evolution of a cold with and without the vitamin surplus?
That said, do not underestimate the health benefits of the placebo effect. It can help a lot. Particularly with anything to do with stress.
As for it being a "scam" - there are enough valid studies that show what this one did, that folks who are deficient that are able to raise their levels tend to be slightly healthier.
There isn't necessarily evidence for supplementation beyond "normal" range, and I do agree that no one should just take high-dose vitamin D supplements without data (tests) that it is necessary.
I'm sure people who supplement or have good D levels also take care of themselves, generally - because they know D is one of the supplements that make a difference both somatic and psychological.
And thus do better with flu/cold.