diff --git a/src/lib/isEmail.js b/src/lib/isEmail.js
index abe465052..a349c71eb 100644
--- a/src/lib/isEmail.js
+++ b/src/lib/isEmail.js
@@ -63,7 +63,7 @@ function validateDisplayName(display_name) {
 
 export default function isEmail(str, options) {
   assertString(str);
-  options = merge(options, default_email_options);
+  options = options ? merge(options, default_email_options) : default_email_options;
 
   if (options.require_display_name || options.allow_display_name) {
     const display_email = str.match(splitNameAddress);
diff --git a/src/lib/isFQDN.js b/src/lib/isFQDN.js
index eb6928fda..1c2f9ed3f 100644
--- a/src/lib/isFQDN.js
+++ b/src/lib/isFQDN.js
@@ -12,7 +12,7 @@ const default_fqdn_options = {
 
 export default function isFQDN(str, options) {
   assertString(str);
-  options = merge(options, default_fqdn_options);
+  options = options ? merge(options, default_fqdn_options) : default_fqdn_options;
 
   /* Remove the optional trailing dot before checking validity */
   if (options.allow_trailing_dot && str[str.length - 1] === '.') {
diff --git a/src/lib/normalizeEmail.js b/src/lib/normalizeEmail.js
index f4349ac1e..02b1b8a96 100644
--- a/src/lib/normalizeEmail.js
+++ b/src/lib/normalizeEmail.js
@@ -170,7 +170,9 @@ function dotsReplacer(match) {
 }
 
 export default function normalizeEmail(email, options) {
-  options = merge(options, default_normalize_email_options);
+  options = options
+    ? merge(options, default_normalize_email_options)
+    : default_normalize_email_options;
 
   const raw_parts = email.split('@');
   const domain = raw_parts.pop();