diff --git a/lib/discourse_tagging.rb b/lib/discourse_tagging.rb
index 044935f5b..77b05dcfc 100644
--- a/lib/discourse_tagging.rb
+++ b/lib/discourse_tagging.rb
@@ -185,14 +185,8 @@ module DiscourseTagging
     end
   end
 
-  # TODO: this is unused?
-  def self.notification_key(tag_id)
-    "tags_notification:#{tag_id}"
-  end
-
-  # TODO: this is unused?
   def self.muted_tags(user)
     return [] unless user
-    UserCustomField.where(user_id: user.id, value: TopicUser.notification_levels[:muted]).pluck(:name).map { |x| x[0,17] == "tags_notification" ? x[18..-1] : nil}.compact
+    TagUser.lookup(user, :muted).joins(:tag).pluck('tags.name')
   end
 end
diff --git a/lib/topic_query.rb b/lib/topic_query.rb
index 49cef6da0..a8e1d77e6 100644
--- a/lib/topic_query.rb
+++ b/lib/topic_query.rb
@@ -597,8 +597,7 @@ class TopicQuery
       if user.nil? || !SiteSetting.tagging_enabled || !SiteSetting.remove_muted_tags_from_latest
         list
       else
-        muted_tags = DiscourseTagging.muted_tags(user)
-        if muted_tags.empty?
+        if !TagUser.lookup(user, :muted).exists?
           list
         else
           showing_tag = if opts[:filter]
@@ -608,17 +607,17 @@ class TopicQuery
             nil
           end
 
-          if muted_tags.include?(showing_tag)
+          if TagUser.lookup(user, :muted).joins(:tag).where('tags.name = ?', showing_tag).exists?
             list # if viewing the topic list for a muted tag, show all the topics
           else
-            arr = muted_tags.map{ |z| "'#{z}'" }.join(',')
-            list.where("EXISTS (
-       SELECT 1
-         FROM topic_custom_fields tcf
-        WHERE tcf.name = 'tags'
-          AND tcf.value NOT IN (#{arr})
-          AND tcf.topic_id = topics.id
-       ) OR NOT EXISTS (select 1 from topic_custom_fields tcf where tcf.name = 'tags' and tcf.topic_id = topics.id)")
+            muted_tag_ids = TagUser.lookup(user, :muted).pluck(:tag_id)
+            list = list.where("
+              EXISTS (
+                SELECT 1
+                  FROM topic_tags tt
+                 WHERE tt.tag_id NOT IN (:tag_ids)
+                   AND tt.topic_id = topics.id
+              ) OR NOT EXISTS (SELECT 1 FROM topic_tags tt WHERE tt.topic_id = topics.id)", tag_ids: muted_tag_ids)
           end
         end
       end
diff --git a/spec/components/topic_query_spec.rb b/spec/components/topic_query_spec.rb
index 1c6e63fce..3461a5d27 100644
--- a/spec/components/topic_query_spec.rb
+++ b/spec/components/topic_query_spec.rb
@@ -178,6 +178,33 @@ describe TopicQuery do
     end
   end
 
+  context 'muted tags' do
+    it 'is removed from new and latest lists' do
+      SiteSetting.tagging_enabled = true
+      SiteSetting.remove_muted_tags_from_latest = true
+
+      muted_tag, other_tag = Fabricate(:tag), Fabricate(:tag)
+
+      muted_topic = Fabricate(:topic, tags: [muted_tag])
+      tagged_topic = Fabricate(:topic, tags: [other_tag])
+      untagged_topic = Fabricate(:topic)
+
+      TagUser.create!(user_id: user.id,
+                      tag_id: muted_tag.id,
+                      notification_level: CategoryUser.notification_levels[:muted])
+
+      topic_ids = topic_query.list_latest.topics.map(&:id)
+      expect(topic_ids).not_to include(muted_topic.id)
+      expect(topic_ids).to include(tagged_topic.id)
+      expect(topic_ids).to include(untagged_topic.id)
+
+      topic_ids = topic_query.list_new.topics.map(&:id)
+      expect(topic_ids).not_to include(muted_topic.id)
+      expect(topic_ids).to include(tagged_topic.id)
+      expect(topic_ids).to include(untagged_topic.id)
+    end
+  end
+
   context 'a bunch of topics' do
     let!(:regular_topic) do
       Fabricate(:topic, title: 'this is a regular topic',