PHP - filter_var no funciona

$email = "Correo@hotmail.com";

echo $email."<---";

$email = filter_var($email, FILTER_SANITIZE_EMAIL);

echo $email."<---";

$email = "Correo@hotmail.com";

if (filter_var($email, FILTER_VALIDATE_EMAIL)) {

  echo("si");

} else {

  echo("no");

}

php -m

php -m | grep 'filter'

Array

(

    [0] => int

    [1] => boolean

    [2] => float

    [3] => validate_regexp

    [4] => validate_domain

    [5] => validate_url

    [6] => validate_email <-- este es el que me interesa

    [7] => validate_ip

    [8] => validate_mac

    [9] => string

    [10] => stripped

    [11] => encoded

    [12] => special_chars

    [13] => full_special_chars

    [14] => unsafe_raw

    [15] => email

    [16] => url

    [17] => number_int

    [18] => number_float

    [19] => magic_quotes

    [20] => callback

)