diff --git a/History.md b/History.md
index f51da8df..f7313199 100644
--- a/History.md
+++ b/History.md
@@ -2,6 +2,7 @@ unreleased
 ==========
 
   * Fix `TypeError` in `res.send` when given `Buffer` and `ETag` header set
+  * perf: skip parsing of entire `X-Forwarded-Proto` header
 
 4.16.1 / 2017-09-29
 ===================
diff --git a/lib/request.js b/lib/request.js
index 3432e677..8bb86a9a 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -315,8 +315,12 @@ defineGetter(req, 'protocol', function protocol(){
 
   // Note: X-Forwarded-Proto is normally only ever a
   //       single value, but this is to be safe.
-  proto = this.get('X-Forwarded-Proto') || proto;
-  return proto.split(/\s*,\s*/)[0];
+  var header = this.get('X-Forwarded-Proto') || proto
+  var index = header.indexOf(',')
+
+  return index !== -1
+    ? header.substring(0, index).trim()
+    : header.trim()
 });
 
 /**