diff --git a/profiles/default/package.use/required-by b/profiles/default/package.use/required-by
index f0e98b640..890b8220f 100644
--- a/profiles/default/package.use/required-by
+++ b/profiles/default/package.use/required-by
@@ -704,3 +704,6 @@ dev-libs/libical vala
 
 # required by net-misc/econnman-1.1-r1
 dev-libs/efl connman
+
+# required by sci-chemistry/votca-xtp-1.6
+sci-libs/hdf5 cxx