diff --git a/Makefile b/Makefile
index ec97152..2cc0e4c 100644
--- a/Makefile
+++ b/Makefile
@@ -2,4 +2,4 @@
 default: ungeli
 
 ungeli: ungeli.c
-	$(CC) -std=gnu99 $^ -lcrypto -Wall -g -o $@
+	$(CC) -O -std=gnu99 $^ -lcrypto -Wall -g -o $@