diff --git a/src/wrapper.ts b/src/wrapper.ts
index 159209c..8eb2375 100644
--- a/src/wrapper.ts
+++ b/src/wrapper.ts
@@ -155,8 +155,16 @@ export class RequestWrapper {
   }
 
   private isJsonResponse<T extends TransformedResponse | AxiosResponse>(response: T) {
-    return response.headers['content-type'] &&
-      response.headers['content-type'].indexOf('application/json') !== -1;
+    let headers: RawAxiosResponseHeaders | AxiosResponseHeaders = {};
+    Object.assign(headers, response.headers);
+    headers = Object.entries(response.headers)
+      .reduce((acc: RawAxiosResponseHeaders | AxiosResponseHeaders, [key, val]) => {
+        acc[key.toLowerCase()] = val.toLowerCase();
+        return acc;
+      }, ({}));
+
+    return headers['content-type'] &&
+      headers['content-type'].indexOf('application/json') !== -1;
   }
 
   private getLogParameters(extraParametersToLog = {}) {