I have been taking a tablespoon of elderberry syrup since early in the COVID era. I was in good health at the beginning. I'd been 6-1/2 years without a cold when I started. I'll be ten years cold-free in September this year (2023). I've tried several other brands. The others taste flat and processed, whereas Elderberry Grove syrup tastes fresh and alive.
I also read the science: Quercetin, which is abundant in elderberry, is a zinc ionophore. That is, it admits zinc through the cell membrane to block RNA polymerase, the enzyme that RNA viruses use to replicate. Add to that Cyanidin, which is a natural molecule abundant in elderberry (moreso than in any other natural source), which activates the SIRT6 gene, one of the key genes in reversing cell and molecular damage in the body. Those who are interested may want to start with Dr David Sinclair's published works, or refer to the educational videos produced by Siim Land (available on YouTube).