Superthrive isn't allowed to be sold in Oregon and several other states.
It's kelp concentrate and vitamins. Kelp contains gibberellins which is where Gibberellic acid/GA3 comes from. It's nothing special and overuse could potentially lead to male parts on female plants because GA3 can be used to reverse a plant to produce feminized pollen for making feminized seeds.
"Another hormone found in kelp is gibberellin (also known as gibberellic acid or GA), which encourage stem growth and elongation. At high concentrations gibberellin can be used to encourage germination of seeds or manipulate gender expression, but at the levels found in kelp it is generally considered a growth stimulant."
I have a theory that some of the additives people are using in excess is a possible cause of many of the hermaphrodite plants people end up growing.
Just out of curiosity what do you think it's going to do? There is nothing super about it and their marketing is straight out of the Snake oil Salesman's playbook.