It means Amazon has not purchased wholesale yet. But HJOE stated they are ahead of projections and Amazon said they are going to allow to have the Hangover Recovery shot sold as well.
I think Amazon buying wholesale is not out of the question in the future. There should be something in the contract that states sales figures and progression options.
Sold by Amazon => Amazon buys the item wholesale and sells it directly to you.
Shipped by Amazon => A seller buy hundreds of an item and has it shipped to an Amazon warehouse. When you order the item, Amazon gets it from the warehouse and ships it to you.