diff --git a/src/Common/HasAttributes.php b/src/Common/HasAttributes.php
index c687ed2..4439fc4 100644
--- a/src/Common/HasAttributes.php
+++ b/src/Common/HasAttributes.php
@@ -27,7 +27,7 @@ trait HasAttributes
      */
     public function __isset($key)
     {
-        return (isset($this->attributes[$key]) || isset($this->relations[$key])) ||
+        return isset($this->attributes[$key]) ||
         ($this->hasGetMutator($key) && ! is_null($this->getAttributeValue($key)));
     }
 
diff --git a/src/Server/RemoteUser.php b/src/Server/RemoteUser.php
index 69aa424..25c1a61 100644
--- a/src/Server/RemoteUser.php
+++ b/src/Server/RemoteUser.php
@@ -39,6 +39,29 @@ public function __construct($id)
         }
     }
 
+    /**
+     * Is this attribute specified on the user?
+     *
+     * @param  string  $key
+     * @return bool
+     */
+    public function __isset($key)
+    {
+        // We read some fields directly from the OAuth token, and so
+        // they can always be considered "set" (even if they're null):
+        if (in_array($key, ['id', 'northstar_id', 'role'])) {
+            return true;
+        }
+
+        // Otherwise, we'll need to load the user's full user profile
+        // attributes & check if requested key is set there:
+        if (! $this->loaded) {
+            $this->loadAttributes();
+        }
+
+        return isset($this->attributes[$key]);
+    }
+
     /**
      * Get an attribute, either from the token on the request or by
      * lazy-loading the full profile from the authorization server.
@@ -59,10 +82,7 @@ public function __get($key)
         // duration of this request. (This instance is kept by the
         // user provider.)
         if (! $this->loaded) {
-            $user = gateway('northstar')->withToken($this->token)->getUser($this->id);
-
-            $this->attributes = $user->toArray();
-            $this->loaded = true;
+            $this->loadAttributes();
         }
 
         if (array_key_exists($key, $this->attributes) || $this->hasGetMutator($key)) {
@@ -71,4 +91,18 @@ public function __get($key)
 
         return null;
     }
+
+    /**
+     * Load the attributes on this 'RemoteUser' by requesting
+     * the corresponding user profile in Northstar.
+     *
+     * @return void
+     */
+    private function loadAttributes()
+    {
+        $user = gateway('northstar')->withToken($this->token)->getUser($this->id);
+
+        $this->attributes = $user->toArray();
+        $this->loaded = true;
+    }
 }