diff --git a/README.md b/README.md
index 15afbc8..ece1810 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ note: a .env file must be made in order to store the relative variable value pro
 ![Alt Text](performance.gif)
 
 ## Enable Profiling
-In order to enable profiling, please use an extension that allows you to modify the document response headers. An example of an extension like that for Chrome is [modheader](https://modheader.com/).
+In order to enable profiling, please use an extension that allows you to modify the document response headers (make sure you create a rule to modify RESPONSE headers, not request headers!). An example of an extension like that for Chrome is [modheader](https://modheader.com/).
 
 ![policy headers](profiling.png)