Any extra overhead when using extract()?

I have a performance question, I'm using extract() to extract a mysql_fetch_array results into variables then use them for output.

So basically does that add any extra uneeded overhead to performance? do you recommend keeping this way or simply use the fetched array directly when i'm outputting?

Thank you

Stop with micro optimization and do Profiling!
http://www.xdebug.org/

Is it okay to do profiling before the application is ready? many things might differ...
so i don't want to code something now and have to change/modify it all later..

Yes as long as the major components are all together and working. I can tell you right now extract doesn't put a dent in your overhead compared to accessing the database.