diff --git a/lib/core/constants.js b/lib/core/constants.js
index 000c0194909..a82a1bc0310 100644
--- a/lib/core/constants.js
+++ b/lib/core/constants.js
@@ -102,10 +102,8 @@ const wellknownHeaderNames = /** @type {const} */ ([
 ])
 
 /** @type {Record<typeof wellknownHeaderNames[number]|Lowercase<typeof wellknownHeaderNames[number]>, string>} */
-const headerNameLowerCasedRecord = {}
-
 // Note: object prototypes should not be able to be referenced. e.g. `Object#hasOwnProperty`.
-Object.setPrototypeOf(headerNameLowerCasedRecord, null)
+const headerNameLowerCasedRecord = Object.create(null)
 
 for (let i = 0; i < wellknownHeaderNames.length; ++i) {
   const key = wellknownHeaderNames[i]
diff --git a/lib/core/util.js b/lib/core/util.js
index 05dd11867d7..e35491091c8 100644
--- a/lib/core/util.js
+++ b/lib/core/util.js
@@ -819,7 +819,9 @@ function errorRequest (client, request, err) {
 const kEnumerableProperty = Object.create(null)
 kEnumerableProperty.enumerable = true
 
-const normalizedMethodRecordsBase = {
+// Note: object prototypes should not be able to be referenced. e.g. `Object#hasOwnProperty`.
+
+const normalizedMethodRecordsBase = Object.setPrototypeOf({
   delete: 'DELETE',
   DELETE: 'DELETE',
   get: 'GET',
@@ -832,17 +834,13 @@ const normalizedMethodRecordsBase = {
   POST: 'POST',
   put: 'PUT',
   PUT: 'PUT'
-}
+}, null)
 
-const normalizedMethodRecords = {
+const normalizedMethodRecords = Object.setPrototypeOf({
   ...normalizedMethodRecordsBase,
   patch: 'patch',
   PATCH: 'PATCH'
-}
-
-// Note: object prototypes should not be able to be referenced. e.g. `Object#hasOwnProperty`.
-Object.setPrototypeOf(normalizedMethodRecordsBase, null)
-Object.setPrototypeOf(normalizedMethodRecords, null)
+}, null)
 
 module.exports = {
   kEnumerableProperty,