diff --git a/ga_login.module b/ga_login.module
index eb48f06..2ae1733 100644
--- a/ga_login.module
+++ b/ga_login.module
@@ -41,10 +41,7 @@ function ga_login_create_access($target_account, $account = NULL) {
     }
     if (user_access('create own login code once', $account)) {
       // check if the user already has a code
-      module_load_include('php', 'ga_login', 'ga_login.class');
-      $ga = new ga_loginGA(10);
-      $username = _ga_login_username($account);
-      return !$ga->hasToken($username);
+      return !_ga_login_account_has_code($account);
     }
   }
   return user_access('create others login codes', $account);
@@ -193,6 +190,26 @@ function _ga_login_code_approve_form($form, &$form_state, $account) {
 }
 
 /**
+ * Check if the given account wants to be forced to use tfa.
+ */
+function _ga_login_force_tfa($account) {
+  if (user_access('login without code', $account)) {
+    return isset($account->data['ga_login_force_tfa']) ? $account->data['ga_login_force_tfa'] : FALSE;
+  }
+  return TRUE;
+}
+
+/**
+ * Check if the given account does have a code.
+ */
+function _ga_login_account_has_code($account) {
+  module_load_include('php', 'ga_login', 'ga_login.class');
+  $ga = new ga_loginGA(10);
+  $username = _ga_login_username($account);
+  return $ga->hasToken($username);
+}
+
+/**
  * Submit handler to create a new code.
  */
 function ga_login_create_form_submit($form, &$form_state) {
@@ -288,7 +305,7 @@ function ga_login_test_form_submit($form, $form_state) {
  */
 function ga_login_form_alter(&$form, &$form_state, $form_id) {
   if ($form_id == 'user_login_block' || $form_id == 'user_login') {
-    array_unshift($form['#validate'],$form['#validate'][0]);
+    array_unshift($form['#validate'], $form['#validate'][0]);
     $form['#validate'][1] = 'ga_login_user_login_validate';
     $form['gacode'] = array(
       '#type' => 'textfield',
@@ -306,6 +323,36 @@ function ga_login_form_alter(&$form, &$form_state, $form_id) {
       $form['links']['#weight'] = 5;
     }
   }
+  elseif ($form_id == 'user_profile_form') {
+    $account = $form['#user'];
+    $register = ($account->uid > 0 ? FALSE : TRUE);
+    // Add some more settings to the user profile form.
+    $form['ga_login'] = array(
+      '#type' => 'fieldset',
+      '#title' => t('Two factor authentication'),
+      '#weight' => 1,
+      '#access' => (!$register && user_access('login without code', $account)),
+    );
+    $form['ga_login']['ga_login_force_tfa'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Protect my account with two-factor-authentication'),
+      '#default_value' => isset($account->data['ga_login_force_tfa']) ? $account->data['ga_login_force_tfa'] : FALSE,
+      '#description' => t('Check this box to force two-factor-authentication during login. If you decide to do so and haven\'t yet created your key, then please also refer to <a href="@url">GA Login</a>.', array('@url' => url('user/' . $account->uid . '/ga_login'))),
+    );
+  }
+}
+
+/**
+ * Implements hook_user_presave().
+ */
+function ga_login_user_presave(&$edit, $account, $category) {
+  if (isset($edit['ga_login_force_tfa'])) {
+    $edit['data']['ga_login_force_tfa'] = $edit['ga_login_force_tfa'];
+    if ($edit['ga_login_force_tfa'] && empty($account->data['ga_login_force_tfa']) && !_ga_login_account_has_code($account)) {
+      // If force tfa got switched on and the user has no code yet, redirect to the code creation page after saving.
+      $_GET['destination'] = url('user/' . $account->uid . '/ga_login');
+    }
+  }
 }
 
 /**
@@ -316,7 +363,7 @@ function ga_login_user_login_validate($form, &$form_state) {
   $name = $form_state['values']['name'];
   $code = $form_state['values']['gacode'];
   $account = user_load_by_name($name);
-  if (!user_access('login without code', $account) || !empty($code) || ($account->uid == 1 && variable_get('ga_login_always_for_uid1', 0))) {
+  if (_ga_login_force_tfa($account) || !empty($code) || ($account->uid == 1 && variable_get('ga_login_always_for_uid1', 0))) {
     module_load_include('php', 'ga_login', 'ga_login.class');
     $ga = new ga_loginGA(10);
     $username = _ga_login_username($account);