There really isn’t one.
if you have been driven to a site to sell you one from a web page that you were viewing… well, at the point of writing this, it is a con. No pills are taking the UK by storm. No such pill exists.
Someone had to say it.
If it were true it would be all over the mainstream news and the scientific community would be on fire. Calories in need to be accounted for; used or stored.