There is a huge difference between brands of herbs, vitamins and minerals, and all "natural" products for that matter. It is Just like the difference in quality between brands for any other type of product . . . one company chooses to go the quality route while another company chooses to become the low-price leader.
An article appearing last year in Nutraceuticals World, July/August 2007, opens the door to the herbal products industry and allows the reader to learn more about concerns that companies have about the raw materials they buy as ingredients in their herbal dietary supplements. This article was written by Dr. Steven Dentali of the AHPA. Even though Dentali is on the staff of a trade association which promotes herbal products (the American Herbal Products Association) his concerns are expressed openly about the unethical practice of allowing raw materials providers to defraud the consumer. These suppliers often come from China.
Take, for example, those botanical products which are used for Dietary Supplements from the Biberry (Vaccinium myrtillus). Dentali says in this article that bilberry extracts are now being found in the market which are adulterated with the chemical dye amaranth, more commonly known as Red Dye #2. This was banned from the food supply in 1976 when the FDA discovered it was a possible carcinogen.
Quality companies (like Indena , the 120 year old leader in the field of bilberry) do assays via HPLC (high pressure liquid chromatography) to ensure the quality of their product. This testing produces an HPLC "fingerprint" which tells them if the tested material identifies with the original appearance of the plant's various compounds. In the case of Bilberry, there are fifteen different biochemicals called "anthocyanins" that create the fingerprint.
Producers of Bilberry extracts are now concerned, as they should be, that raw materials providers often substitute these fake-bilberry agents. Regularly, HPLC fingerprinting done on bilberry products shows a different appearance than the pure botanical agent would via the same test.
Rhodiola is another herb which could be faked. A popular new Rhodiola product is MIND BODY & SPIRIT, which is the purest form of Siberian Rhodiola roseain the world. Each batch of that Rhodiola is HPLC fingerprinted and standardized to the dozen biochemicals which make for the Rhodiola effect on the brain (mental clarity, energy, mood uplift, etc). It is entirely possible, however, (and in fact it has been reported) that some of the biochemicals in Rhodiola can be found cheap and easily in other plants. Unscrupulous raw materials suppliers can take advantage of companies that don't do thorough HPLC fingerprinting. In those cases, Rosavins and Salidrosides (two of the active biochemical compounds in Rhodiola) may appear to be from Rhodiola rosea, the plant of choice, but in actuality they could be substitutes from another species.
Cheap brands of Rhodiola are now showing up in drug stores, Internet sites and vitamin shops. Herbal analysts are concerned this one may be the next herb to be tainted by adulteration.
In all matters, whether it is herbs or anything else, you generally get what you pay for. A botanical extract from one company may not even resemble the extract sold by another company. That's why it is so important for consumers to rely on companies that perform their own clinical trials. And the results of those clinical trials do not in any way support other brands of products that may not check their raw materials suppliers as rigorously. Always buy from companies that perform their own studies, as they use this research to ensure a quality product free from adulteration.