diff --git a/plugins/wasm-go/extensions/transformer/main.go b/plugins/wasm-go/extensions/transformer/main.go
index 1263ee812..896526698 100644
--- a/plugins/wasm-go/extensions/transformer/main.go
+++ b/plugins/wasm-go/extensions/transformer/main.go
@@ -39,6 +39,7 @@ func init() {
 		wrapper.ProcessRequestBodyBy(onHttpRequestBody),
 		wrapper.ProcessResponseHeadersBy(onHttpResponseHeaders),
 		wrapper.ProcessResponseBodyBy(onHttpResponseBody),
+		wrapper.WithRebuildMaxMemBytes[TransformerConfig](200*1024*1024),
 	)
 }
 
@@ -343,11 +344,12 @@ func onHttpRequestHeaders(ctx wrapper.HttpContext, config TransformerConfig, log
 	isValidRequestContent := isValidRequestContentType(contentType)
 	isBodyChange := config.reqTrans.IsBodyChange()
 	needBodyMapSource := config.reqTrans.NeedBodyMapSource()
+	hasRequestBody := ctx.HasRequestBody()
 
-	log.Debugf("contentType:%s, isValidRequestContent:%v, isBodyChange:%v, needBodyMapSource:%v",
-		contentType, isValidRequestContent, isBodyChange, needBodyMapSource)
+	log.Debugf("contentType:%s, isValidRequestContent:%v, isBodyChange:%v, needBodyMapSource:%v, hasRequestBody:%v",
+		contentType, isValidRequestContent, isBodyChange, needBodyMapSource, hasRequestBody)
 
-	if isBodyChange && isValidRequestContent {
+	if isBodyChange && isValidRequestContent && hasRequestBody {
 		delete(hs, "content-length")
 	}
 
@@ -361,7 +363,7 @@ func onHttpRequestHeaders(ctx wrapper.HttpContext, config TransformerConfig, log
 	ctx.SetContext("headers", hs)
 	ctx.SetContext("querys", qs)
 
-	if !isValidRequestContent || (!isBodyChange && !needBodyMapSource) {
+	if !hasRequestBody || !isValidRequestContent || (!isBodyChange && !needBodyMapSource) {
 		ctx.DontReadRequestBody()
 	} else if needBodyMapSource {
 		// we need do transform during body phase
diff --git a/plugins/wasm-go/extensions/transformer/main_test.go b/plugins/wasm-go/extensions/transformer/main_test.go
index 3660e3c37..e789a7969 100644
--- a/plugins/wasm-go/extensions/transformer/main_test.go
+++ b/plugins/wasm-go/extensions/transformer/main_test.go
@@ -424,6 +424,43 @@ func TestRequest_MapFromBody_DelaysHeaderTransform(t *testing.T) {
 	})
 }
 
+func TestRequest_MapFromBody_NoRequestBodyDoesNotPause(t *testing.T) {
+	test.RunTest(t, func(t *testing.T) {
+		host, status := test.NewTestHost(configJSON(map[string]any{
+			"reqRules": []map[string]any{
+				{
+					"operate":   "map",
+					"mapSource": "body",
+					"headers": []map[string]any{
+						{"fromKey": "user.id", "toKey": "X-User-Id"},
+					},
+				},
+				{
+					"operate": "add",
+					"headers": []map[string]any{
+						{"key": "X-Static", "value": "ok"},
+					},
+				},
+			},
+		}))
+		defer host.Reset()
+		require.Equal(t, types.OnPluginStartStatusOK, status)
+
+		action := host.CallOnHttpRequestHeaders([][2]string{
+			{":authority", "test.com"},
+			{":path", "/p"},
+			{":method", "POST"},
+			{"content-type", "application/json"},
+		}, test.WithEndOfStream(true))
+		require.Equal(t, types.ActionContinue, action, "request without body must not wait for body callback")
+
+		got := headersToMap(host.GetRequestHeaders())
+		require.Equal(t, []string{"ok"}, got["x-static"])
+		require.NotContains(t, got, "x-user-id")
+		host.CompleteHttp()
+	})
+}
+
 // --- regex template ---
 
 func TestRequest_Headers_AddWithHostPattern(t *testing.T) {