diff --git a/src/atomvm_spectrometer.erl b/src/atomvm_spectrometer.erl
index a5d0413..9f95b38 100644
--- a/src/atomvm_spectrometer.erl
+++ b/src/atomvm_spectrometer.erl
@@ -358,10 +358,10 @@ parse_ecosystem_args([Unknown | _], _Opts) ->
 parse_supported_args([], Opts) ->
     Opts;
 parse_supported_args(["--module", Mod | Rest], Opts) ->
-    Bin = spectrometer_utils:normalize_module_name(Mod),
+    Bin = spectrometer_utils:normalize_module_name(Mod, true),
     parse_supported_args(Rest, Opts#{module => Bin});
 parse_supported_args(["-m", Mod | Rest], Opts) ->
-    Bin = spectrometer_utils:normalize_module_name(Mod),
+    Bin = spectrometer_utils:normalize_module_name(Mod, true),
     parse_supported_args(Rest, Opts#{module => Bin});
 parse_supported_args(["--cache", Dir | Rest], Opts) ->
     parse_supported_args(Rest, Opts#{cache_dir => Dir});
diff --git a/src/spectrometer_help.erl b/src/spectrometer_help.erl
index 5b51312..ab78546 100644
--- a/src/spectrometer_help.erl
+++ b/src/spectrometer_help.erl
@@ -184,6 +184,7 @@ usage_supported() ->
         "\n"
         "Options:\n"
         "  --module <mod>     Show functions for a specific OTP module\n"
+        "                     (Elixir modules can omit the Elixir. prefix)\n"
         "  -m <mod>           Same as --module\n"
         "  --erl              Show only Erlang functions (exclude Elixir)\n"
         "  --ex               Filter output to Elixir modules (does not rename or strip module prefixes)\n"
@@ -194,6 +195,8 @@ usage_supported() ->
         "  spectrometer supported\n"
         "  spectrometer supported --module gen_server\n"
         "  spectrometer supported -m lists\n"
+        "  spectrometer supported -m Elixir.List\n"
+        "  spectrometer supported -m List\n"
         "  spectrometer supported --ex\n"
         "  spectrometer supported --erl\n"
         "  spectrometer supported -c /tmp/custom_cache\n"
diff --git a/src/spectrometer_utils.erl b/src/spectrometer_utils.erl
index a9b41a7..db9053e 100644
--- a/src/spectrometer_utils.erl
+++ b/src/spectrometer_utils.erl
@@ -25,7 +25,6 @@ directory removal, and GitHub URL normalization for deduplication.
     is_elixir_module_name/1,
     make_temp_dir/1,
     normalize_github_url/1,
-    normalize_module_name/1,
     normalize_module_name/2,
     normalize_platform_name/1,
     purge_dir/1,
@@ -405,35 +404,21 @@ os_temp_dir() ->
             "/tmp"
     end.
 
--doc "Detect if a module name is Elixir-style (starts with literal Elixir. prefix).".
+-doc "Detect if a module name is capitalized (Elixir style).".
 -spec is_elixir_module_name(atom() | string() | binary()) -> boolean().
 is_elixir_module_name(Atom) when is_atom(Atom) ->
     is_elixir_module_name(atom_to_list(Atom));
 is_elixir_module_name(Str) when is_list(Str) ->
-    case Str of
-        "Elixir." ++ _ -> true;
+    case normalize_module_name(Str, true) of
+        <<"Elixir.", _/binary>> -> true;
         _ -> false
     end;
 is_elixir_module_name(Bin) when is_binary(Bin) ->
-    case Bin of
+    case normalize_module_name(Bin, true) of
         <<"Elixir.", _/binary>> -> true;
         _ -> false
     end.
 
--doc """
-Normalize module name without Elixir prefixing. 'Elixir.GPIO' -> <<"Elixir.GPIO">>,
-'GPIO' -> <<"GPIO">>, 'lists' -> <<"lists">>. Delegates to normalize_module_name/2 with
-ElixirFlag = false. For Elixir-prefixed output, use normalize_module_name/2 with
-ElixirFlag = true. Returns a binary().
-""".
--spec normalize_module_name(string() | atom() | binary()) -> binary().
-normalize_module_name(Atom) when is_atom(Atom) ->
-    normalize_module_name(atom_to_list(Atom));
-normalize_module_name(Str) when is_list(Str) ->
-    normalize_module_name(Str, false);
-normalize_module_name(Str) when is_binary(Str) ->
-    normalize_module_name(Str, false).
-
 -doc """
 Normalize module name.
 
diff --git a/test/atomvm_spectrometer_tests.erl b/test/atomvm_spectrometer_tests.erl
index e6ecca9..5e4eb4b 100644
--- a/test/atomvm_spectrometer_tests.erl
+++ b/test/atomvm_spectrometer_tests.erl
@@ -455,6 +455,40 @@ parse_supported_args_short_module_test_() ->
         ?assertEqual(<<"maps">>, maps:get(module, Opts))
     end}.
 
+parse_supported_args_elxir_module_test_() ->
+    {"normalizes Elixir module names with prefix", fun() ->
+        % Capitalized module name should get Elixir. prefix
+        {command, supported, Opts1} = atomvm_spectrometer:parse_args([
+            "supported", "-m", "List"
+        ]),
+        ?assertEqual(<<"Elixir.List">>, maps:get(module, Opts1)),
+        % Already-prefixed module name stays as-is
+        {command, supported, Opts2} = atomvm_spectrometer:parse_args([
+            "supported", "-m", "Elixir.List"
+        ]),
+        ?assertEqual(<<"Elixir.List">>, maps:get(module, Opts2)),
+        % Erlang module name (lowercase) stays as-is
+        {command, supported, Opts3} = atomvm_spectrometer:parse_args([
+            "supported", "-m", "lists"
+        ]),
+        ?assertEqual(<<"lists">>, maps:get(module, Opts3)),
+        % Long form --module: Capitalized module name should get Elixir. prefix
+        {command, supported, Opts4} = atomvm_spectrometer:parse_args([
+            "supported", "--module", "List"
+        ]),
+        ?assertEqual(<<"Elixir.List">>, maps:get(module, Opts4)),
+        % Long form --module: Already-prefixed module name stays as-is
+        {command, supported, Opts5} = atomvm_spectrometer:parse_args([
+            "supported", "--module", "Elixir.List"
+        ]),
+        ?assertEqual(<<"Elixir.List">>, maps:get(module, Opts5)),
+        % Long form --module: Erlang module name (lowercase) stays as-is
+        {command, supported, Opts6} = atomvm_spectrometer:parse_args([
+            "supported", "--module", "lists"
+        ]),
+        ?assertEqual(<<"lists">>, maps:get(module, Opts6))
+    end}.
+
 parse_supported_args_erl_test_() ->
     {"parses --erl flag", fun() ->
         {command, supported, Opts} = atomvm_spectrometer:parse_args(
diff --git a/test/spectrometer_elixir_tests.erl b/test/spectrometer_elixir_tests.erl
index f200083..af8d30c 100644
--- a/test/spectrometer_elixir_tests.erl
+++ b/test/spectrometer_elixir_tests.erl
@@ -42,25 +42,11 @@ parse_query_8_formats_test() ->
 %% normalize_module tests
 %% =============================================================================
 
-normalize_gpio_test() ->
-    ?assertEqual(
-        <<"GPIO">>,
-        spectrometer_utils:normalize_module_name("GPIO")
-    ).
-
-normalize_elixir_gpio_test() ->
-    ?assertEqual(
-        <<"Elixir.GPIO">>,
-        spectrometer_utils:normalize_module_name("Elixir.GPIO")
-    ).
-
-normalize_lists_test() ->
+normalize_with_flag_test() ->
     ?assertEqual(
         <<"lists">>,
-        spectrometer_utils:normalize_module_name("lists")
-    ).
-
-normalize_with_flag_test() ->
+        spectrometer_utils:normalize_module_name("lists", false)
+    ),
     ?assertEqual(
         <<"Elixir.GPIO">>,
         spectrometer_utils:normalize_module_name("GPIO", true)
@@ -80,9 +66,11 @@ is_elixir_module_name_elxir_prefix_test() ->
         true, spectrometer_utils:is_elixir_module_name("Elixir.MyModule")
     ).
 
-is_elixir_module_name_lowercase_test() ->
+is_elixir_module_name_case_test() ->
     ?assertEqual(false, spectrometer_utils:is_elixir_module_name("lists")),
     ?assertEqual(false, spectrometer_utils:is_elixir_module_name("maps")),
-    % Uppercase without Elixir prefix is no longer considered Elixir
-    ?assertEqual(false, spectrometer_utils:is_elixir_module_name("GPIO")),
-    ?assertEqual(false, spectrometer_utils:is_elixir_module_name("MyModule")).
+    ?assertEqual(true, spectrometer_utils:is_elixir_module_name("GPIO")),
+    ?assertEqual(true, spectrometer_utils:is_elixir_module_name("MyModule")),
+    % Binary inputs
+    ?assertEqual(true, spectrometer_utils:is_elixir_module_name(<<"GPIO">>)),
+    ?assertEqual(false, spectrometer_utils:is_elixir_module_name(<<"lists">>)).
diff --git a/test/spectrometer_utils_tests.erl b/test/spectrometer_utils_tests.erl
index 913718d..9714e1a 100644
--- a/test/spectrometer_utils_tests.erl
+++ b/test/spectrometer_utils_tests.erl
@@ -361,29 +361,9 @@ start_applications_success_test_() ->
         ?_assertEqual(ok, spectrometer_utils:start_applications())}.
 
 %% =============================================================================
-%% normalize_module_name/1 and /2 tests
+%% normalize_module_name/2 tests
 %% =============================================================================
 
-normalize_module_name_string_test_() ->
-    {"normalizes string module name",
-        ?_assertEqual(
-            <<"Elixir.GPIO">>,
-            spectrometer_utils:normalize_module_name("Elixir.GPIO")
-        )}.
-
-normalize_module_name_atom_test_() ->
-    {"normalizes atom module name",
-        ?_assertEqual(
-            <<"Elixir.GPIO">>,
-            spectrometer_utils:normalize_module_name('Elixir.GPIO')
-        )}.
-
-normalize_module_name_non_elixir_atom_test_() ->
-    {"normalizes atom without Elixir prefix",
-        ?_assertEqual(
-            <<"lists">>, spectrometer_utils:normalize_module_name(lists)
-        )}.
-
 normalize_module_name_2_atom_test_() ->
     {"normalize_module_name/2 with atom and ElixirFlag=true",
         ?_assertEqual(