Personable vs. Professional Supplements

Hi all!

I'm currently writing supplementals for the B/MD programs I'm applying to, and was wondering: is it better to write essays that are personable and really show my personality, or stay professional and mellow down a little bit?

I'd like to think I have a really big personality, and my personal statement is very reflective of that. Just, how much is too much when it comes to these programs?

Thanks!