diff --git a/src/net/http/httputil/dump.go b/src/net/http/httputil/dump.go
index 7affe5e61a9..8a42023b2a9 100644
--- a/src/net/http/httputil/dump.go
+++ b/src/net/http/httputil/dump.go
@@ -243,15 +243,9 @@ func DumpRequest(req *http.Request, body bool) ([]byte, error) {
 	fmt.Fprintf(&b, "%s %s HTTP/%d.%d\r\n", valueOrDefault(req.Method, "GET"),
 		reqURI, req.ProtoMajor, req.ProtoMinor)
 
-	absRequestURI := strings.HasPrefix(req.RequestURI, "http://") || strings.HasPrefix(req.RequestURI, "https://")
-	if !absRequestURI {
-		host := req.Host
-		if host == "" && req.URL != nil {
-			host = req.URL.Host
-		}
-		if host != "" {
-			fmt.Fprintf(&b, "Host: %s\r\n", host)
-		}
+	_, ok := req.Header["Host"]
+	if ok {
+		fmt.Fprintf(&b, "Host: %s\r\n", req.Header.Get("Host"))
 	}
 
 	chunked := len(req.TransferEncoding) > 0 && req.TransferEncoding[0] == "chunked"
diff --git a/src/net/http/httputil/dump_test.go b/src/net/http/httputil/dump_test.go
index c20c054865f..42404b7187d 100644
--- a/src/net/http/httputil/dump_test.go
+++ b/src/net/http/httputil/dump_test.go
@@ -18,6 +18,7 @@ import (
 	"strings"
 	"testing"
 	"time"
+	_ "unsafe"
 )
 
 type eofReader struct{}
@@ -57,7 +58,6 @@ var dumpTests = []dumpTest{
 		Body: []byte("abcdef"),
 
 		WantDump: "GET /search HTTP/1.1\r\n" +
-			"Host: www.google.com\r\n" +
 			"Transfer-Encoding: chunked\r\n\r\n" +
 			chunk("abcdef") + chunk(""),
 	},
@@ -151,7 +151,6 @@ var dumpTests = []dumpTest{
 			"Accept-Encoding: gzip\r\n\r\n" +
 			strings.Repeat("a", 8193),
 		WantDump: "POST / HTTP/1.1\r\n" +
-			"Host: post.tld\r\n" +
 			"Content-Length: 8193\r\n\r\n" +
 			strings.Repeat("a", 8193),
 	},
@@ -383,8 +382,11 @@ func mustNewRequest(method, url string, body io.Reader) *http.Request {
 	return req
 }
 
+//go:linkname readRequest net/http.readRequest
+func readRequest(b *bufio.Reader) (*http.Request, error)
+
 func mustReadRequest(s string) *http.Request {
-	req, err := http.ReadRequest(bufio.NewReader(strings.NewReader(s)))
+	req, err := readRequest(bufio.NewReader(strings.NewReader(s)))
 	if err != nil {
 		panic(err)
 	}
diff --git a/src/net/http/httputil/example_test.go b/src/net/http/httputil/example_test.go
index 6c107f83900..9c065562f3f 100644
--- a/src/net/http/httputil/example_test.go
+++ b/src/net/http/httputil/example_test.go
@@ -47,7 +47,7 @@ func ExampleDumpRequest() {
 	fmt.Printf("%s", b)
 
 	// Output:
-	// "POST / HTTP/1.1\r\nHost: www.example.org\r\nAccept-Encoding: gzip\r\nContent-Length: 75\r\nUser-Agent: Go-http-client/1.1\r\n\r\nGo is a general-purpose language designed with systems programming in mind."
+	// "POST / HTTP/1.1\r\nAccept-Encoding: gzip\r\nContent-Length: 75\r\nUser-Agent: Go-http-client/1.1\r\n\r\nGo is a general-purpose language designed with systems programming in mind."
 }
 
 func ExampleDumpRequestOut() {