I've been taking 1000 IUs daily, for the last 20 years, skipping summers (during which I would attempt sun exposure), while continuously being within acceptable medians for my age. I sure hope what I am typing now makes sense :-)
Any chance you have an identical twin who has not?
I’d get a cold at least once a year and the flu every few years. I started taking 5K IUs of D3 daily in 2019 and haven't had a cold or flu since then.
Flu spread among all humans (not just those supplementing vit D) was massively reduced in recent years because of a little thing called COVID-19 and all the social distancing/lockdowns that led to...
I live in a household of 4, everyone has continued to get colds at least once a year including covid but I have not had any symptoms of infection and attribute that to my daily intake of D3.
4000 daily during flu winter seasons. It probably works.
Older folks can't make D naturally, so you may want to skip your summer skipping soon.
For all we know they are only 20 years old.
People haven’t been doing things since birth, obviously and especially taking pills. Also this is a thread on dementia, not typically indicated in young adults.