diff --git a/share/config.fish b/share/config.fish
index d85fd1e185..c564e45b27 100644
--- a/share/config.fish
+++ b/share/config.fish
@@ -158,6 +158,7 @@
 #
 if status --is-login
     if command -sq /usr/libexec/path_helper
+        and not set -q __NIX_DARWIN_SET_ENVIRONMENT_DONE
         # Adapt construct_path from the macOS /usr/libexec/path_helper
         # executable for fish; see
         # https://opensource.apple.com/source/shell_cmds/shell_cmds-203/path_helper/path_helper.c.auto.html .