diff --git a/src/Composer/Command/UpdateCommand.php b/src/Composer/Command/UpdateCommand.php
index e37109271..4d9462910 100644
--- a/src/Composer/Command/UpdateCommand.php
+++ b/src/Composer/Command/UpdateCommand.php
@@ -48,7 +48,7 @@ class UpdateCommand extends BaseCommand
                 new InputOption('dry-run', null, InputOption::VALUE_NONE, 'Outputs the operations but will not execute anything (implicitly enables --verbose).'),
                 new InputOption('dev', null, InputOption::VALUE_NONE, 'DEPRECATED: Enables installation of require-dev packages (enabled by default, only present for BC).'),
                 new InputOption('no-dev', null, InputOption::VALUE_NONE, 'Disables installation of require-dev packages.'),
-                new InputOption('lock', null, InputOption::VALUE_NONE, 'Updates the lock file hash to suppress warning about the lock file being out of date, and also updates the packages\' mirrors/URLs if they changed.'),
+                new InputOption('lock', null, InputOption::VALUE_NONE, 'Overwrites the lock file hash to suppress warning about the lock file being out of date without updating package versions. Package metadata like mirrors and URLs are updated if they changed.'),
                 new InputOption('no-install', null, InputOption::VALUE_NONE, 'Skip the install step after updating the composer.lock file.'),
                 new InputOption('no-autoloader', null, InputOption::VALUE_NONE, 'Skips autoloader generation'),
                 new InputOption('no-scripts', null, InputOption::VALUE_NONE, 'Skips the execution of all scripts defined in composer.json file.'),