First time I experimented with it to make feminized seeds. It wasn't as strong as the forums recommend. But still worked. I can't remember if the next colloidal silver I bought was recommended strength, but it worked too.
It's a very strong antimicrobial, found in first aid/ medicines shelves in health food stores. It will cure staph A infections without antibiotics, even when cellulitis is spreading. Seen this with my own eyes when living in the tropics. There used to be bandages with a silver mesh in the gauze. They absolutely soothed cuts and healed really quick without Neosporin needed.