I think it normally has a slight effect on mood; "contributes to lift inhibition of action" or words close to this,from a seller on ebay,don't remember but I think he was copying from the original notice.
But is it not known that any drug with this effect can also have the opposite effect on some people ? Especially at this kind of dose you are mentioning ? the seller says ordinary treatment is three times 200 mg a day.
Also,as mentioned here and there on this forum,beware of products of unclear origins.
The powder is bought from Smart Powders.
From my little research on the "opposite effect" you are talking about, I have read that it make you act "colder", getting away emotion, but for some people it can make their dopamine receptors more sensitive (I am not an expert and not absolutely sure about that).