Health food

Before buying health food based on advertising I suggest you show at least a little cynicism.
I find it irritating to hear on the radio every day advertisements for all sorts of health foods that I have good reason to believe are not effective at what they are supposed to do. But when they actually have side effects it becomes even more serious.

So I suggest you do a simple Google search. Search for the product and "side effects".
or "[product] may cause"
lets start with Colloidal silver
Note both provide some interesting potential effects.

or selenium

meanwhile something like deer velvet is pretty harmless (besides the potential for allergic reaction) although I wouldn't bother paying much money to eat it....

although a bit more research will show the limited risks you are exposed to including
toxins that get into the velvet when they catch the deer and chop off the horns

(Dalefield RR, Oehme FW. Deer velvet antler: some unanswered questions on toxicology. Vet Hum Toxicol. 1999;41:39–41.)