diff --git a/backend/main.py b/backend/main.py
index 9833f5a..9a96f91 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1112,20 +1112,25 @@ def delete_user(user_id: int, user=Depends(require_role("admin"))):
     diaries = conn.execute("SELECT id, name, ingredients FROM user_diary WHERE user_id = ?", (user_id,)).fetchall()
     transferred = 0
     if diaries:
-        # Load admin's diary and public recipes for dedup
-        admin_diaries = conn.execute("SELECT name, ingredients FROM user_diary WHERE user_id = ?", (user["id"],)).fetchall()
-        public_recipes = conn.execute(
-            "SELECT r.name, GROUP_CONCAT(ri.oil_name || ':' || ri.drops) as ings "
-            "FROM recipes r LEFT JOIN recipe_ingredients ri ON r.id = ri.recipe_id GROUP BY r.id"
-        ).fetchall()
-        existing = {}
+        # Build set of ingredient fingerprints from admin diary + public recipes
+        def _ings_key(ings_json):
+            """Normalize ingredients to a comparable key."""
+            try:
+                ings = json.loads(ings_json) if isinstance(ings_json, str) else []
+                return tuple(sorted((i.get("oil") or i.get("oil_name", ""), i.get("drops", 0)) for i in ings))
+            except Exception:
+                return ()
+        existing_keys = set()
+        admin_diaries = conn.execute("SELECT ingredients FROM user_diary WHERE user_id = ?", (user["id"],)).fetchall()
         for row in admin_diaries:
-            existing[row["name"]] = row["ingredients"]
-        for row in public_recipes:
-            existing[row["name"]] = row["ings"] or ""
+            existing_keys.add(_ings_key(row["ingredients"]))
+        public_recipes = conn.execute("SELECT id FROM recipes").fetchall()
+        for pr in public_recipes:
+            pub_ings = conn.execute("SELECT oil_name, drops FROM recipe_ingredients WHERE recipe_id = ?", (pr["id"],)).fetchall()
+            existing_keys.add(tuple(sorted((r["oil_name"], r["drops"]) for r in pub_ings)))
         for d in diaries:
-            # Check if same name+ingredients exists in admin diary or public
-            is_dup = d["name"] in existing
+            d_key = _ings_key(d["ingredients"])
+            is_dup = d_key in existing_keys and d_key != ()
             if is_dup:
                 conn.execute("DELETE FROM user_diary WHERE id = ?", (d["id"],))
             else: