My immune system preservation team for the last 18 months
Modified Low-Carb diet (under 25 grams sugar a day, avoiding grains and seed oils)
5000 IU Vitamin D3,
900mg - 1800mg Omega-3
200 mg magnesium bisglycinate once in am once at night
zinc,
Melatonin at night
I don't take these yet in capsule form but they're reputably helpful
K2 -- essential when one takes large doses of Vitamin D3,
selenium,
probiotics (capsule or fermented food),
black seed oil
Dr. Robert Lustig ("The Hacking of the American Mind") [1]
Dr. Roger Seheult ("MedCram") [2]
Dr. Rhonda Patrick ("Found My Fitness" [3])
take variations of this supplement regimen.
What's good enough for them is good enough for me.
1.
https://robertlustig.com/metabolical/
2.
https://blog.medcram.com/covid-19/vitamin-d-and-covid-19-the-evidence-for-prevention-and-treatment-of-coronavirus/
3.
https://www.foundmyfitness.com/episodes/covid-19-episode-1
(and many others)