diff --git a/classes/Profile.php b/classes/Profile.php
index 5d7946bcd8..51b1fb72a8 100644
--- a/classes/Profile.php
+++ b/classes/Profile.php
@@ -89,7 +89,7 @@ class Profile extends Managed_DataObject
         if ($this->_user === -1) {
             $this->_user = User::getKV('id', $this->id);
         }
-        if (!is_a($this->_user, 'User')) {
+        if (!($this->_user instanceof User)) {
             throw new NoSuchUserException(array('id'=>$this->id));
         }