diff --git src/bp-messages/bp-messages-functions.php src/bp-messages/bp-messages-functions.php
index 39a3c5507..6699597b4 100644
--- src/bp-messages/bp-messages-functions.php
+++ src/bp-messages/bp-messages-functions.php
@@ -315,10 +315,6 @@ function messages_delete_thread( $thread_ids, $user_id = 0 ) {
  * @return int|null Message ID if the user has access, otherwise null.
  */
 function messages_check_thread_access( $thread_id, $user_id = 0 ) {
-	if ( empty( $user_id ) ) {
-		$user_id = bp_loggedin_user_id();
-	}
-
 	return BP_Messages_Thread::check_access( $thread_id, $user_id );
 }