diff --git a/app/services/user.js b/app/services/user.js
index 4d6611a..057f38e 100644
--- a/app/services/user.js
+++ b/app/services/user.js
@@ -123,7 +123,9 @@ class UserService {
     const username_lc = userDefinition.username.toLowerCase();
 
     userDefinition.displayName = striptags(userDefinition.displayName.trim());
-    userDefinition.bio = striptags(userDefinition.bio.trim());
+    if (userDefinition.bio) {
+      userDefinition.bio = striptags(userDefinition.bio.trim());
+    }
 
     this.log.info('updating user', { userDefinition });
     await User.updateOne(