Is Zenbev an effective sleep aid?

A lot of people have asked about Zenbev, the "organic sleeping aid" available in health food stores. This combination of pumpkin seed extract and dextrose with some rice starch and guar gum was developed by psychiatrist Craig Hudson based on the assumption that the tryptophan-rich protein in the seed releases tryptophan upon digestion, and that insulin secretion in response to the dextrose component leads to other amino acids being absorbed into muscle cells leaving trytophan free to cross the blood brain barrier. This amino acid is the precursor both for serotonin and melatonin with melatonin production being favoured in the dark. Since melatonin is known to enhance sleep, Zenbev should work, at least in theory. Hudson quotes a couple of pilot studies but I can't find any proper randomized double blind trials. There appears to be plenty of anecdotal evidence and the product sells well, especially in Europe. The Natural Products Directorate in Canada has granted Zenbev an NPN (Natural Product Number) giving it some legitimacy, although the requirements for this are not very stringent. Emphasis is on safety, not efficacy. Demonstration of efficacy can come from theory or even anecdotes. There is probably no great risk in trying this product, which based on known biochemistry may actually work. Zenbev is cdertified as "organic" but that is irrelevant. It is also advertised to be s GMO-free which is just a marketing gimmick, as is the term "natural." Yes pumpkin seeds and dextrose are natural. But so what? So is morphine. And that can put you to sleep permanently.