I straghtened my hair many moons ago (after I had a really dodgy perm…don’t ask!)……….so can’t vouch for the Boots one.
But basically it’s the same process/chemicals as a perm just not using little rollers to get the curl…………
Depends on whether you want to use the product just the once or will continue??? If it will be an ongoing thing then I probably wouldn’t recommend it, unless you went to the hairdressers to have it done professionally (and cost you an arm and a leg).