Zinc. What is it used for? How much is too much?

[Cleansing]

I take this multvitamin which contains 15mg of zinc, that's the RDA, But I also have a separate bottle of zinc with 50 mg of Zinc. Now I' reading all over the net, and Im reading all kinds of stuff about Zinc. To your knowledge, what does it do? Im using it for my skin problems, but they say it boosts your immune system as well. I hearing anything over 100 mg is too much. but some sites are saying 50 mg is too much.

What do you know about Zinc supplements.?