Since herbs are not regulated as drugs, no legal
standard exists for their processing, harvesting, or packaging. Supplements do
not have to be manufactured according to any quality control guidelines and
ingredients do not need to be standardized. Manufacturers could be buying herbs,
without testing them to determine the potency of ingredients and do not need to
ensure they are not contaminated. Since products can be marketed in a
unrestricted regulatory environment, consumers must realize that this lack of
standardization will lead to variation in purity and strength of ingredients
used in different brands.
Lack of Scientific Data
Most available research on herbal supplements has been done in Europe, Asia, and India but there is a paucity of data that has been generated in the U.S. Scientific research on both vitamin/mineral and herbal supplements is needed, but is costly, and the government cannot do it alone. DSHEA has helped to establish an office on Dietary Supplements that is working with the newly established National Center on Complementary Alternative Medicine within the National Institutes of Health to conduct more test clinical trials to determine the efficacy, and biological action of botanicals and dietary supplements.
In the meantime, manufacturers rely on existing data available from other studies which often have limitations and cannot be considered as conclusive. Many studies are based on animal data rather than human clinical trials. Often industry claims are based on testimonials, case studies or small sample size rather randomized, controlled, double-blind clinical studies. The lack of standardization of herbal products makes it even more difficult to compare efficacy of claims between different brands.
Currently, industry has not attempted to spend the millions of dollars required to conduct clinical trials as is done by pharmaceutical companies since supplements can be brought to market without it (as long as treatment for disease claims are not made). Supplements contain naturally available ingredients that are not patented, and are not exclusive. This makes it less likely that industry will want to pay for conducting a clinical trial since other manufacturers can market a product containing the same ingredients.