diff --git a/libexec/pyenv-exec b/libexec/pyenv-exec
index f77227b2..6380dfc9 100755
--- a/libexec/pyenv-exec
+++ b/libexec/pyenv-exec
@@ -4,7 +4,8 @@
 #
 # Usage: pyenv exec [-E|--environment] <command> [arg1 arg2...]
 #
-#    -E  Modify Python runtime environment, such as $PYTHONHOME, for the called executable.
+#    -E  Set PYTHONHOME and LD_LIBRARY_PATH envvars for the running command. This allows to run programs that embed Python without using rpath or exact library path.
+#         WARNING! For the running command and its child processes, this will break linkage for programs that expect to be linked to system libpython!
 #
 # Runs an executable by first preparing PATH so that the selected Python
 # version's `bin' directory is at the front.