diff --git a/lib/install/audit.js b/lib/install/audit.js
index 23a60beb31138..f372b425a6fd4 100644
--- a/lib/install/audit.js
+++ b/lib/install/audit.js
@@ -87,7 +87,7 @@ function fetchAudit (href, body) {
   const opts = pacoteOpts()
   return registryFetch(href, {
     method: 'POST',
-    headers: { 'Content-Encoding': 'gzip', 'Content-Type': 'application/json' },
+    headers: { 'content-encoding': 'gzip', 'content-type': 'application/json' },
     config: npm.config,
     npmSession: opts.npmSession,
     projectScope: npm.projectScope,