diff --git a/packages/remix/src/utils/web-fetch.ts b/packages/remix/src/utils/web-fetch.ts
index a98fbd2c6b2f..5c1e895cbbc3 100644
--- a/packages/remix/src/utils/web-fetch.ts
+++ b/packages/remix/src/utils/web-fetch.ts
@@ -88,7 +88,7 @@ export const normalizeRemixRequest = (request: RemixRequest): Record<string, any
     contentLengthValue = '0';
   }
 
-  if (request.body !== null) {
+  if (request.body !== null && request[bodyInternalsSymbol]) {
     const totalBytes = request[bodyInternalsSymbol].size;
     // Set Content-Length if totalBytes is a number (that is not NaN)
     if (typeof totalBytes === 'number' && !Number.isNaN(totalBytes)) {