How to: get_user_meta – BuddyPress [closed]

Inside the loop, you can get the currently iterated user id using bp_get_member_user_id().

Also, it’s best practice to use bp_get_user_meta(), because it works better with certain kinds of BP plugins (multi-network, etc).

Thus:

if ( bp_has_members() ) {
    while ( bp_members() ) {
        bp_the_member();
        $user_last = bp_get_user_meta( bp_get_member_user_id(), 'last_name', true );
    }
}