How to reload user profile from script file in PowerShell

I want to reload my user profile from a script file. I thought that dot sourcing it from within the script file would do the trick, but it doesn't work:

# file.ps1
. $PROFILE

However, it does work if I dot source it from PowerShell's interpreter.

Why do I want to do this?

I run this script every time I update my profile and want to test it, so I'd like to avoid having to restart PowerShell to refresh the environment.

So, the approach that you marked as the answer may work inside the Powershell command prompt, but it doesn't work inside PowerShell ISE (which, to me, provides a superior PowerShell session) and probably won't work right in other PowerShell environments.

Here's a script that I have been using for a while, and it has worked very well for me in every environment. I simply put this function into my Profile.ps1 at ~\Documents\WindowsPowerShell, and whenever I want to reload my profile, I dot-source the function, i.e.

. Reload-Profile

Here's the function:

function Reload-Profile {
    @(
        $Profile.AllUsersAllHosts,
        $Profile.AllUsersCurrentHost,
        $Profile.CurrentUserAllHosts,
        $Profile.CurrentUserCurrentHost
    ) | % {
        if(Test-Path $_){
            Write-Verbose "Running $_"
            . $_
        }
    }
}