we invest capital in forex but only that much that we can afford and if we get loss we can bear it..and when it comes to invest all our capital in forex market then the risk level is very high but there are people who are ready to take risks and they invest there capital fully but according to me its not a goood idea because as i said risk level is very high so if u can able to take the risk you can go for full capital investment otherwise just trade wisely and smartly