diff --git a/sentry_sdk/integrations/flask.py b/sentry_sdk/integrations/flask.py
index 67c87b64f6..e1755f548b 100644
--- a/sentry_sdk/integrations/flask.py
+++ b/sentry_sdk/integrations/flask.py
@@ -261,6 +261,5 @@ def _add_user_to_event(event):
 
         try:
             user_info.setdefault("username", user.username)
-            user_info.setdefault("username", user.email)
         except Exception:
             pass