fejl i update SQL

hvad er der galt med denne sql .. jeg får fejlen
"You have an error in your SQL syntax near '( fullname, username, password, email, address, zipcode, phone) where username =' at line 1"


$res = ("UPDATE users set ( fullname, username, password, email, address, zipcode, phone) where username = '$authenticatedUser'
VALUES ('$fullname', '$username', '$password', '$email', '$address', '$zipcode', '$phone')") ;