diff --git a/app/services/user.js b/app/services/user.js
index 057f38e..bd9cb22 100644
--- a/app/services/user.js
+++ b/app/services/user.js
@@ -147,7 +147,9 @@ 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 for admin', { userDefinition });
     await User.updateOne(