diff --git a/pkg/promlib/client/transport.go b/pkg/promlib/client/transport.go
index 429befa1527..0a4e2dccfd7 100644
--- a/pkg/promlib/client/transport.go
+++ b/pkg/promlib/client/transport.go
@@ -37,7 +37,6 @@ func middlewares(logger log.Logger, httpMethod string) []sdkhttpclient.Middlewar
 	middlewares := []sdkhttpclient.Middleware{
 		// TODO: probably isn't needed anymore and should by done by http infra code
 		middleware.CustomQueryParameters(logger),
-		sdkhttpclient.CustomHeadersMiddleware(),
 	}
 
 	// Needed to control GET vs POST method of the requests
diff --git a/pkg/promlib/client/transport_test.go b/pkg/promlib/client/transport_test.go
index a0d23aa2f2f..fcf3b115468 100644
--- a/pkg/promlib/client/transport_test.go
+++ b/pkg/promlib/client/transport_test.go
@@ -22,6 +22,6 @@ func TestCreateTransportOptions(t *testing.T) {
 		opts, err := CreateTransportOptions(context.Background(), settings, backend.NewLoggerWith("logger", "test"))
 		require.NoError(t, err)
 		require.Equal(t, http.Header{"Foo": []string{"bar"}}, opts.Header)
-		require.Equal(t, 2, len(opts.Middlewares))
+		require.Equal(t, 1, len(opts.Middlewares))
 	})
 }