diff --git a/zephyr/static/js/compose.js b/zephyr/static/js/compose.js
index b955d539a9..9c7360ec1e 100644
--- a/zephyr/static/js/compose.js
+++ b/zephyr/static/js/compose.js
@@ -157,7 +157,7 @@ function update_fade () {
         faded_to.stream = $('#stream').val();
         faded_to.subject = $('#subject').val();
     } else {
-        faded_to.reply_to = $('#private_message_recipient').val();
+        faded_to.reply_to = util.normalize_recipients($('#private_message_recipient').val());
     }
 
     compose.update_faded_messages();
diff --git a/zephyr/static/js/util.js b/zephyr/static/js/util.js
index cab8d3934b..cf5087c167 100644
--- a/zephyr/static/js/util.js
+++ b/zephyr/static/js/util.js
@@ -193,6 +193,13 @@ exports.same_sender = function util_same_sender(a, b) {
             (a.sender_email === b.sender_email));
 };
 
+exports.normalize_recipients = function (recipients) {
+    recipients = $.map(recipients.split(','), $.trim);
+    recipients = $.grep(recipients, function (s) { return s.length>0; });
+    recipients.sort();
+    return recipients.join(',');
+};
+
 // Avoid URI decode errors by removing characters from the end
 // one by one until the decode succeeds.  This makes sense if
 // we are decoding input that the user is in the middle of