diff --git a/app/controllers/experiments_controller.rb b/app/controllers/experiments_controller.rb
index acb418e61..67cc028e6 100644
--- a/app/controllers/experiments_controller.rb
+++ b/app/controllers/experiments_controller.rb
@@ -47,7 +47,7 @@ class ExperimentsController < ApplicationController
   end
 
   def assigned_users
-    render json: User.where(id: @experiment.user_assignments.select(:user_id)),
+    render json: @experiment.users,
            each_serializer: UserSerializer,
            user: current_user
   end