This link highlights a sad story of young woman in the U.K. who died using a Raspberry Ketone mix supplement. They also talk about similar problems in the U.S. with OTC supplements. So, buyer beware.
https://www.yahoo.com/health/death-by-raspberry-ketones-and-caffeine-powder-104865586867.html
https://www.yahoo.com/health/death-by-raspberry-ketones-and-caffeine-powder-104865586867.html