diff --git a/deepeval/models/detoxify_model.py b/deepeval/models/detoxify_model.py
index d6bcf9a07..c5a896767 100644
--- a/deepeval/models/detoxify_model.py
+++ b/deepeval/models/detoxify_model.py
@@ -4,7 +4,8 @@
 
 class DetoxifyModel(DeepEvalBaseModel):
     def __init__(self, model_name: str | None = None, *args, **kwargs):
-        assert model_name in ["original", "unbiased", "multilingual"], "Invalid model. Available variants: original, unbiased, multilingual"
+        if model_name is not None:
+            assert model_name in ["original", "unbiased", "multilingual"], "Invalid model. Available variants: original, unbiased, multilingual"
         model_name = 'original' if model_name is None else model_name
         super().__init__(model_name, *args, **kwargs)