diff --git a/src/wg-quick/darwin.bash b/src/wg-quick/darwin.bash
index 4a3240c..0eef3d9 100755
--- a/src/wg-quick/darwin.bash
+++ b/src/wg-quick/darwin.bash
@@ -101,7 +101,7 @@ get_real_interface() {
 add_if() {
 	export WG_DARWIN_UTUN_NAME_FILE="/var/run/wireguard/$INTERFACE.name"
 	mkdir -m 0700 -p "/var/run/wireguard/"
-	cmd wireguard-go utun
+	cmd "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" utun
 	get_real_interface
 }
 
diff --git a/src/wg-quick/linux.bash b/src/wg-quick/linux.bash
index 38ccad2..9139e7f 100755
--- a/src/wg-quick/linux.bash
+++ b/src/wg-quick/linux.bash
@@ -86,9 +86,9 @@ add_if() {
 	local ret
 	if ! cmd ip link add "$INTERFACE" type wireguard; then
 		ret=$?
-		[[ -e /sys/module/wireguard ]] || ! command -v wireguard-go >/dev/null && return $ret
+		[[ -e /sys/module/wireguard ]] || ! command -v "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" >/dev/null && exit $ret
 		echo "[!] Missing WireGuard kernel module. Falling back to slow userspace implementation."
-		cmd wireguard-go "$INTERFACE"
+		cmd "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" "$INTERFACE"
 	fi
 }