Non-duplication of emails on broadcasts

Hello. I’ve just run a broadcast with the tags of several lists, but it has duplicated many of the emails instead of only sending to unique users. How do I gather different tagged lists into one broadcast without duplication?

Many thanks in advance.

In a real broadcast that shouldn’t happen. What do you mean by broadcast? Sending emails through campaign builder is not called a broadcast and will send duplicate emails if told to do so.