diff --git a/contact/utilities/utils.py b/contact/utilities/utils.py
index d279c88..41f09d5 100644
--- a/contact/utilities/utils.py
+++ b/contact/utilities/utils.py
@@ -180,7 +180,8 @@ def build_reply_prefix(prefix: str, message: str) -> str:
         sender_text = re.sub(r"^(?:>>|<<)\s*(?:\[[^]]+\]\s*)?", "", sender_text)
         sender_match = re.search(r"(.+?)\s*:\s*$", sender_text)
         sender = sender_match.group(1).strip() if sender_match else "me"
-    excerpt = " ".join(message.replace("\x00", "").split())[:REPLY_EXCERPT_LENGTH]
+    message_without_reply_marker = re.sub(r"^<Re:\s*[^>]*>\s*", "", message.replace("\x00", ""))
+    excerpt = " ".join(message_without_reply_marker.split())[:REPLY_EXCERPT_LENGTH]
     return f"<Re: {sender}: {excerpt}> "
 
 
diff --git a/tests/test_contact_ui.py b/tests/test_contact_ui.py
index f092415..13c8dad 100644
--- a/tests/test_contact_ui.py
+++ b/tests/test_contact_ui.py
@@ -120,6 +120,14 @@ class ContactUiTests(unittest.TestCase):
 
         self.assertEqual(reply, "<Re: LRY: Thank> ")
 
+    def test_build_reply_prefix_does_not_nest_an_existing_reply_marker(self) -> None:
+        reply = contact_ui.build_reply_prefix(
+            "[06:27:25] >> xT1e: ",
+            "<Re: CATS: Woot!> Woot indeed",
+        )
+
+        self.assertEqual(reply, "<Re: xT1e: Woot > ")
+
     def test_handle_ctrl_r_prefills_reply_for_message_at_cursor(self) -> None:
         ui_state.current_window = 1
         ui_state.channel_list = ["Primary"]