I prepare tincures in a variety of bases, distilled water or alcohol depending on tincture.
The medicinal mushrooms are not generally available from the supermarket. You might be lucky to find reishi, dried or fresh.
I source most of mine from the wild. If buying dried it's hard to know how old they are - i think freshest is the key to potency of the good benefits. Many of the really amazing medicinal shrooms like chaga don't grow in my habitat so i source tinctures online.
With the viral load your blood reveals it'll be interesting to see if the mushroom tinctures cause numbers on next tests to drop.
Certainly worth trying if you've never tried them before.