diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index 2b0d3f5aa8862..cdbef673643e8 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -324,7 +324,8 @@ def unique(values):
     Hash table-based unique. Uniques are returned in order
     of appearance. This does NOT sort.
 
-    Significantly faster than numpy.unique. Includes NA values.
+    Significantly faster than numpy.unique for long enough sequences.
+    Includes NA values.
 
     Parameters
     ----------