diff --git a/source/content-scripts/features/anonymize-usernames.ts b/source/content-scripts/features/anonymize-usernames.ts
index 404ec6f..977e095 100644
--- a/source/content-scripts/features/anonymize-usernames.ts
+++ b/source/content-scripts/features/anonymize-usernames.ts
@@ -42,5 +42,5 @@ function generateReplacements(elements: HTMLElement[]): Record<string, string> {
 }
 
 function usernameFromElement(element: HTMLElement): string {
-  return (element.textContent ?? "<unknown>").trim();
+  return (element.textContent ?? "<unknown>").trim().toLowerCase();
 }