Only 60 percent of the oral joint supplements analyzed recently by Canadian researchers contained the level of glucosamine specified on their labels. [...] Fourteen of the products tested matched their label claim of glucosamine content, nine did not and four of those varied "substantially," meaning they deviated more than 30 percent from the label claim. [...] The researchers also noted a disparity between the dosing instructions on the products and the standard recommended dose of 10 grams per day, which is based on previous research. The average label dose was half of the standard recommended dose. [...] These findings, say the researchers, reveal the need for better oversight and regulatory control of supplement contents to protect consumers.
Now, EoR feels compelled to point out this wasn't actually a study, it was a short communication. Also, it's not clear how many samples of the various products were tested. Nonetheless, it is clear that relying on supplements to provide a specific dose (or, indeed, any dose) is pretty much a hit and miss affair.
This is not a one-off in the alternative and complementary supplements market. Pan Pharmaceuticals in recent history in Australia were shown to provide what could only be called a fairly random quality control of their products.
Of course, if you're not sure that your product is effective, you could always try adding some real pharmaceutical drugs to it.
So: what's in that supplement/alternative treatment/herbal mix you're taking? How do you know? Is the dose of any active ingredients as stated? Is it less? Is it higher? What are the effects of under/overdosing? What standards (if any) does it have to adhere to? Are these the same as registered pharmaceuticals?