diff --git a/geomagio/api/secure/SessionMiddleware.py b/geomagio/api/secure/SessionMiddleware.py
index c757c8b33439d88e550577c44e32ab88fa8c273f..04c621c18d6058340ca6aaa40f0334e883d10aaf 100644
--- a/geomagio/api/secure/SessionMiddleware.py
+++ b/geomagio/api/secure/SessionMiddleware.py
@@ -116,7 +116,7 @@ class SessionMiddleware:
         max_age: int = None,
     ):
         headers = MutableHeaders(scope=message)
-        headers.append("Cache-Control")
+        headers.append("Cache-Control", "no-cache")
         headers.append(
             "Set-Cookie",
             f"{self.session_cookie}={value};"
diff --git a/geomagio/api/ws/data.py b/geomagio/api/ws/data.py
index 76107cb4a4c236987f7766ec542203ae7f5b2aaa..053474c1d3834931d81d5d1e18dee1041575cbf5 100644
--- a/geomagio/api/ws/data.py
+++ b/geomagio/api/ws/data.py
@@ -121,8 +121,7 @@ def format_timeseries(
     else:
         data = IAGA2002Writer.format(timeseries, elements)
         media_type = "text/plain"
-    headers = {"allow_origins": "*", "max_age": "", "allow_headers": "*"}
-    return Response(data, media_type=media_type, headers=headers)
+    return Response(data, media_type=media_type)
 
 
 def get_timeseries(data_factory: TimeseriesFactory, query: DataApiQuery) -> Stream: