diff --git a/lib/galaxy/config/__init__.py b/lib/galaxy/config/__init__.py
index ca78874969eb..9b2d435ae393 100644
--- a/lib/galaxy/config/__init__.py
+++ b/lib/galaxy/config/__init__.py
@@ -594,7 +594,7 @@ def admin_users(self):
     @admin_users.setter
     def admin_users(self, value):
         self._admin_users = value
-        self.admin_users_list = listify(value)
+        self.admin_users_list = listify(value, do_strip=True)
 
     def is_admin_user(self, user: Optional["User"]) -> bool:
         """Determine if the provided user is listed in `admin_users`."""