diff --git a/app/javascript/flavours/glitch/styles/components/status.scss b/app/javascript/flavours/glitch/styles/components/status.scss
index 889bcaec04..b656f0baf7 100644
--- a/app/javascript/flavours/glitch/styles/components/status.scss
+++ b/app/javascript/flavours/glitch/styles/components/status.scss
@@ -69,6 +69,11 @@
       font-style: italic;
     }
 
+    sub {
+      font-size: smaller;
+      text-align: sub;
+    }
+
     ul, ol {
       margin-left: 1em;
 
diff --git a/app/lib/sanitize_config.rb b/app/lib/sanitize_config.rb
index 0a87bf6dfb..23d0a418fe 100644
--- a/app/lib/sanitize_config.rb
+++ b/app/lib/sanitize_config.rb
@@ -20,7 +20,7 @@ class Sanitize
     end
 
     MASTODON_STRICT ||= freeze_config(
-      elements: %w(p br span a abbr del pre blockquote code b strong i em h1 h2 h3 h4 h5 ul ol li),
+      elements: %w(p br span a abbr del pre blockquote code b strong u sub i em h1 h2 h3 h4 h5 ul ol li),
 
       attributes: {
         'a'          => %w(href rel class title),