diff --git a/docs/USAGE.md b/docs/USAGE.md
index 753dcf59..7023692d 100644
--- a/docs/USAGE.md
+++ b/docs/USAGE.md
@@ -436,6 +436,6 @@ Every `Result` object returned by the engine supports the following methods:
 
 To format a **List** of results, use the `formatter`:
 - `into_json(results_list)`
-- `into_csv(results_list)`
+- `into_csv(results_list, include_header=True)` — pass `include_header=False` when appending to a CSV that already has a header, to avoid writing it twice.
 
 ---
diff --git a/tests/test_formatter.py b/tests/test_formatter.py
index 59f8017e..1d3d67f2 100644
--- a/tests/test_formatter.py
+++ b/tests/test_formatter.py
@@ -1,9 +1,10 @@
-from user_scanner.core.formatter import into_csv, into_json
+from user_scanner.core.formatter import CSV_HEADER, into_csv, into_json
 from user_scanner.core.result import Result
 
 
 def test_get_result_output_formats():
     res = Result.available(username="alice", site_name="ExampleSite", category="Cat")
+    res2 = Result.available(username="bob", site_name="ExampleSite", category="Cat")
 
     out_console = res.get_console_output()
     assert "Not Found" in out_console
@@ -14,6 +15,23 @@ def test_get_result_output_formats():
     assert '"username": "alice"' in out_json
     assert '"site_name": "ExampleSite"' in out_json
 
+    # Test CSV output with header included(Default behavior)
     out_csv = into_csv([res])
     assert "alice" in out_csv
     assert "ExampleSite" in out_csv
+
+    # Test CSV output with header excluded
+    out_csv_no_header = into_csv([res], include_header=False)
+    assert "alice" in out_csv_no_header
+    assert "ExampleSite" in out_csv_no_header
+    assert out_csv_no_header.count(CSV_HEADER) == 0
+
+    # Test CSV output with multiple results and header included
+    first = into_csv([res], include_header=True)
+    second = into_csv([res2], include_header=False)
+
+    full = first + "\n" + second
+    
+    assert full.count(CSV_HEADER) == 1
+    assert "alice" in full
+    assert "bob" in full
diff --git a/user_scanner/__main__.py b/user_scanner/__main__.py
index 3c2c188e..a14d2778 100644
--- a/user_scanner/__main__.py
+++ b/user_scanner/__main__.py
@@ -695,13 +695,14 @@ def main():
                 print(G + f"\n[+] JSON Results saved to {t_output}" + Style.RESET_ALL)
 
             elif args.format == "csv":
-                content_csv = formatter.into_csv(t_results)
                 try:
                     with open(t_output, "r", encoding="utf-8") as init_file:
                         has_content = init_file.read().strip() != ""
                 except Exception:
                     has_content = False
 
+                content_csv = formatter.into_csv(t_results, include_header=not has_content)
+
                 with open(t_output, "a", encoding="utf-8") as f:
                     if has_content:
                         f.write("\n")
diff --git a/user_scanner/core/formatter.py b/user_scanner/core/formatter.py
index 28364e4b..5d0a73ef 100644
--- a/user_scanner/core/formatter.py
+++ b/user_scanner/core/formatter.py
@@ -15,8 +15,8 @@ def get_json_data(results: List[Result]) -> list:
     return [r.to_dict() for r in results]
 
 
-def into_csv(results: List[Result]) -> str:
-    return CSV_HEADER + "\n" + "\n".join(result.to_csv() for result in results)
+def into_csv(results: List[Result], include_header: bool=True) -> str:
+    return CSV_HEADER + "\n" + "\n".join(result.to_csv() for result in results) if include_header else "\n".join(result.to_csv() for result in results)
 
 
 def into_pdf(