People recommending herbal supplements often advise, “Be sure to buy a standardized product from a manufacturer you trust.” That’s easier said than done, and trust has little to do with it.
“Standardized” means that the active ingredient is known, and that each dose contains the same amount of that ingredient and has the same absorption profile. An aspirin tablet, brand-name or otherwise, contains 325 milligrams of acetylsalicylic acid, and its effects and side effects are understood. Some herbal supplements are labeled “standardized,” too, and suggested dosages are specified on the labels. But this is all guesswork. If the active ingredient hasn’t been identified—and in most herbals, this is the case—how can the manufacturer figure out how much you need to take?
Even when a botanical is standardized for one or another identifiable ingredient, that may not actually be the active ingredient, or the herb may also contain other active substances. That’s how plants are— very complicated, chemically speaking. And some herbal supplements have been shown to have virtually no active ingredients at all.
Moreover, there are no validated analyses for botanical products and no legal definition of standardization for them.