I think there is no such thing as the right dose. It all depends on each one of us. If we can take a relatively higher dose without feeling anything wrong, then I guess it is just fine to take that dose. On the other hand, there are also other people who can't take a high dose as their body reacts immediately. If for you 4 IU to 6 IU is the recommended dose for bodybuilding. For the others, the ideal dose might be 6 IU to 10 IU.