diff --git a/modules/accounts/email.nix b/modules/accounts/email.nix
index d57528e0a..1e32ae665 100644
--- a/modules/accounts/email.nix
+++ b/modules/accounts/email.nix
@@ -109,7 +109,9 @@ let
         type = types.bool;
         default = false;
         description = ''
-          Whether to use STARTTLS.
+          Whether to use STARTTLS. This is discouraged and should be avoided if
+          possible. See <https://datatracker.ietf.org/doc/html/rfc8314> for
+          more.
         '';
       };