Q: What exactly is a standardized extract?
JVW: As the term “standardized extract” typically refers to herbal medicine, I’ll let my colleague and regular Nutrition & Healing columnist Kerry Bone field this one. Here is what Kerry has to say:
KB: The term “standardized extract” gets thrown around a lot in herbal medicine. But there’s actually no set definition for it, so, in many cases, it means different things to different people.
Part of the confusion and controversy over the issue is probably due to the fact that there are actually different types of standardized extracts. Based on how they’re made, standardized extracts can be classified into three basic types.
Galenical-type extracts are the most common form of standardized extract. They’re same sort of traditional alcohol-water liquid extracts or tinctures used for centuries by herbalists and naturopaths, but they’ve just been dried for use in tablets. They are not highly concentrated and generally contain the full spectrum of phytochemicals found in the original herb. Examples include standardized extracts of St. John’s wort, devil’s claw, horse chestnut, Echinacea, and kava.
The second type of standardized extract is a highly concentrated extract. This version is made by a refining process that limits some of the phytochemicals in the extract. The best-known example is Ginkgo biloba extract.
The last variety of standardized extract is called a selective phytochemical extract. These are similar to highly concentrated extracts, but in this case a particular phytochemical group is selectively removed from the herb. Essential oils, milk thistle, grape seed extract, evening primrose oil, and turmeric that contains mostly curcumin are good examples of selective phytochemical extracts.
