diff --git a/litellm/proxy/auth/auth_utils.py b/litellm/proxy/auth/auth_utils.py
index 13afe992f0f..92f0d496543 100644
--- a/litellm/proxy/auth/auth_utils.py
+++ b/litellm/proxy/auth/auth_utils.py
@@ -498,13 +498,13 @@ def _has_user_setup_sso():
 
 def get_end_user_id_from_request_body(request_body: dict) -> Optional[str]:
     # openai - check 'user'
-    if "user" in request_body:
-        return request_body["user"]
+    if "user" in request_body and request_body["user"] is not None:
+        return str(request_body["user"])
     # anthropic - check 'litellm_metadata'
     end_user_id = request_body.get("litellm_metadata", {}).get("user", None)
     if end_user_id:
-        return end_user_id
+        return str(end_user_id)
     metadata = request_body.get("metadata")
-    if metadata and "user_id" in metadata:
-        return metadata["user_id"]
+    if metadata and "user_id" in metadata and metadata["user_id"] is not None:
+        return str(metadata["user_id"])
     return None
diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 2c126e54c03..053cf30b59e 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -1049,7 +1049,6 @@ async def update_database(  # noqa: PLR0915
                         response_obj=completion_response,
                         start_time=start_time,
                         end_time=end_time,
-                        end_user_id=end_user_id,
                     )
 
                     payload["spend"] = response_cost
diff --git a/litellm/proxy/spend_tracking/spend_tracking_utils.py b/litellm/proxy/spend_tracking/spend_tracking_utils.py
index c48ff105c01..cbe97cc388a 100644
--- a/litellm/proxy/spend_tracking/spend_tracking_utils.py
+++ b/litellm/proxy/spend_tracking/spend_tracking_utils.py
@@ -29,9 +29,7 @@ def _is_master_key(api_key: str, _master_key: Optional[str]) -> bool:
     return False
 
 
-def get_logging_payload(
-    kwargs, response_obj, start_time, end_time, end_user_id: Optional[str]
-) -> SpendLogsPayload:
+def get_logging_payload(kwargs, response_obj, start_time, end_time) -> SpendLogsPayload:
 
     from litellm.proxy.proxy_server import general_settings, master_key
 
@@ -58,9 +56,17 @@ def get_logging_payload(
         usage = dict(usage)
     id = cast(dict, response_obj).get("id") or kwargs.get("litellm_call_id")
     api_key = metadata.get("user_api_key", "")
-    standard_logging_payload: Optional[StandardLoggingPayload] = kwargs.get(
-        "standard_logging_object", None
+    standard_logging_payload = cast(
+        Optional[StandardLoggingPayload], kwargs.get("standard_logging_object", None)
     )
+
+    if standard_logging_payload is not None:
+        end_user_id = standard_logging_payload["metadata"].get(
+            "user_api_key_end_user_id"
+        )
+    else:
+        end_user_id = None
+
     if api_key is not None and isinstance(api_key, str):
         if api_key.startswith("sk-"):
             # hash the api_key