diff --git a/guix/transformations.scm b/guix/transformations.scm
index c050af2de8..a289f81219 100644
--- a/guix/transformations.scm
+++ b/guix/transformations.scm
@@ -996,6 +996,8 @@ building for ~a instead of ~a, so tuning cannot be guessed~%")
   (display (G_ "
       --with-patch=PACKAGE=FILE
                          add FILE to the list of patches of PACKAGE"))
+  (display (G_ "
+      --tune[=CPU]       tune relevant packages for CPU--e.g., \"skylake\""))
   (display (G_ "
       --with-configure-flag=PACKAGE=FLAG
                          append FLAG to the configure flags of PACKAGE"))