I am looking for a suggestion for a natural herb that can help with estrogen levels in menstration but that do not have isoflavones?

Sorry there is none: Don't believe what you hear from friends, see on tv, or read on the internet. People generally don't need any "help" with their estrogen -- if they do, they need a medical evaluation and appropriate medical therapy. What they don"t need is something where they don't know what's in it, what it's supposed to do, how to monitor it, and whether it will make them sick or harm them. Be safe, not sorry!