Hi Steve,
Well that's probably because it's just a combination of Epsom Salt, any Calcium Salt like Calcium Sulfate and maybe some Iron Sulfate. These are easy to find at bulk prices and that's what the GH Boosters are all about.
Here's a tip: When these people don't list the contents of the package, it's usually because the contents are something ridiculously easy to find and to reproduce yourself. When the vendor knows that the material is either difficult to find, have complicated sounding names, is highly toxic to handle, or is proprietary then they have no problems listing the package contents.
Calcium and Magnesium are very easy to find online, at the Chemist's, or maybe even in the supermarket. All this mumbo-jumbo about "special shrimp product" is just another illusion because it's the same stuff we know, repackaged in a box having a picture of a shrimp on it and endowed with a mysterious sounding name, so it appears to be exotic and otherwise unobtainable. I'll bet the fact that it's "only available in Germany" gives it that extra marketing sizzle.
Cheers,