diff --git a/rpg/enzyme.py b/rpg/enzyme.py
index f0878e81ae530bb2293ad360061a48176233b259..9bfcb193cd8a5675247acd1977d920d7d75e1620 100644
--- a/rpg/enzyme.py
+++ b/rpg/enzyme.py
@@ -252,14 +252,16 @@ def user_creation_enzyme(all_enzymes):
     .. warning:: It could be a problem to immediately use the new enzyme (see in-code warning)
     """
     add_enzyme = "y"
+
+    # All enzymes name
+    all_name_enz = set()
+
+    # Get all used names
+    for enz in all_enzymes:
+        all_name_enz.add(enz.name)
+
     # Adding enzyme
     while add_enzyme == "y":
-        # All enzymes name
-        all_name_enz = set()
-
-        # Get all used names
-        for enz in all_enzymes:
-            all_name_enz.add(enz.name)
 
         # Name of the enzyme
         name_new_enz = input("Name of the new enzyme?\n")
@@ -317,5 +319,8 @@ def user_creation_enzyme(all_enzymes):
         # Write in the user-defined enzymes file
         new_enz.write_enzyme_in_user_file()
 
+        # Add it to known names
+        all_name_enz.add(new_enz.name)
+
         # End of this new enzyme
         add_enzyme = input("Add an other enzyme? (y/n)\n")