diff --git a/src/synapse_registration/registration/templates/registration/complete_registration.html b/src/synapse_registration/registration/templates/registration/complete_registration.html
index a5f87c0..26e917e 100644
--- a/src/synapse_registration/registration/templates/registration/complete_registration.html
+++ b/src/synapse_registration/registration/templates/registration/complete_registration.html
@@ -22,7 +22,7 @@
             <p class="help is-danger">{{ form.registration_reason.errors }}</p>
         </div>
         <p class="help">
-            Sending this form will create a Matrix account for you and reserve your username. However, you will not be able to log in until an administrator approves your registration. Please provide a reason for your registration to help us expedite the approval process.
+            Sending this form will create a Matrix account for you and reserve your username. However, you will not be able to log in until an administrator approves your registration. Please provide a reason for your registration to help us expedite the approval process. Note that you will not be able to register the same username again if your registration is rejected, so please make sure to provide a valid reason.
         </p>
         {% if legal_links %}
             <p class="help">