There are simply too many pleiotropic effects of sun-light and -warmth, to be aware of them all: Mitochondrial endogenous melatonin synthesis (which isn't reached by supplementation), nitric oxide in the vascular system; microbiome, immune (beyond vitamin D), and neurotransmitters modulation - to name a few.
Well once in 25 years a singular 1-month lasting fever, I don't consider really that robust. I even had the illusion in youth of a really strong immunity, since I overcame so many onslaughts apparently without difficulties. However, all those infection (malarias, bilharzia, amoebae, tubercles, etc.) in reality all damaged almost all organ or metabolic systems. I got the repair bill not surprisingly around age 40, when resilience and endogenous repair usually declines.
I do have clear mainstays in my supplements, with clear correlations to whole remissions. But there are too many, to give each a full trial on their own. Therefore, I copy the Ayurvedic approach, where a combination of low dosed mutually supportive extracts show greater synergistic effects, than high-doses of individual herbs. I do feel really different to many ME/CFS, who allegedly can feel differences in taking a new supplement within days. As I posted just the day before yesterday on phoenix rising:
Nattokinase I trialed low dose together with serrapeptase, papain and mainly bromelain. And, as with most individual nutrients, nothing isolated to report.
A post later (there on phoenix rising), I did mention the main nutrients, which did show surprising isolated effects. But neither of them would have been able to cause the strong synergy for such improbable remissions, as from PAD, COPD or PEMs.
Despite my stunning success with vitamin C, I never succeeded to enthuse anyone about its high dose applications with active viral infections:
http://www.doctoryourself.com/titration.html - it seems just too otherworldly and inconvenient for most. To dose so many grams down to every 20 minutes, for overcoming viral infections. But it would work in most cases, once the aversion to ingest so much of an acidic powder during 1 day overcome. Thought, I should mention anyway.