The Consumer Guide to Herbs
In this guide...
Why Take Herbs?
Which Product Types are Best?
Concentration vs. Potency—a Key Distinction
Herbs Teas and Air-Dried, Encapsulated Herbs
Freeze-Dried Herbs
Extracts (liquid or dried)
Guaranteed Potency Extracts
Standardized Extracts
Crude Extracts
Extracts: Which Dosage Forms are Best?
Encapsulated Dried Extracts
Liquid Alcohol Extracts
Liquid Glycerin Extracts
Browse Our Herb Department
Why Take Herbs?
Scientific research into traditional medicinal herbs has been a foundation of modern medicine for more than 150 years. Even today, up to three-quarters of all pharmaceutical drugs contain compounds derived from plants, or variations of plant compounds. For example, aspirin is a synthetic (man made) variation on salicylic acid from white willow bark, a pain-relieving herb used by native Americans. As adjuncts to standard health care, specific herbal medicines offer unique benefits in three areas:
- Added therapeutic choices
- Unique preventive health benefits
- Stress-resistance
Herbs are widely used and prescribed in Europe, and form the basis of medical care throughout most of the developing world. But herbs occupy a precarious position on the fringes of American health care, often ignored, dismissed as unproved, or suppressed as dangerous or fraudulent by mainstream medical institutions.
If herbs are as useful as advocates claim, why aren't herbal products, and information about their benefits, more available? Current U.S. law only permits health claims to be made only for FDA-approved drugs. But there is no financial incentive for manufacturers to apply to the FDA for approval of drug claims for herbs—a process that costs drug companies an average of $200 million per product. There is no incentive to spend this money researching herbs and botanical chemicals, because it is very hard to obtain the patent protection that is considered a necessary requirement before investing such enormous sums.
This strong financial disincentive has kept the benefits of many well-researched herbs from the general public.
Which Product Types are Best?
Herbal products come in one of five dose forms, which can be ranked in terms of likely relative potency and longevity:
FAIR-GOOD: Herb teas (loose or tea bags)
GOOD: Air-Dried (encapsulated)
BETTER: Freeze-Dried (encapsulated)
BETTER: Liquid Extracts (alcohol- or glycerin-base)
BEST: Dried Extracts (encapsulated or "solid")
Concentration vs. Potency: A Key Distinction
In addition to understanding other differences among the five basic forms, it is important to grasp the distinction between concentration (strength) and potency:
- Concentration (strength) is a measure of how much herb was used to make each gram or fluid ounce of finished product. Concentration may or may not correlate with medicinal potency.
- Potency is a measure of biological activity in the body. An herbal product could be very strong in terms of concentration, but weak in potency because it was made from herb deficient in active compounds. Your best, if not definitive, assurance of potency is to choose a "guaranteed potency" or "standardized" extract, or a highly concentrated crude extract (liquid or dried) from a reputable manufacturer.
What Are the Pros and Cons of the Five Dosage Forms?
Herb Teas—(Air-Dried, Encapsulated Herbs)
Air-dried, encapsulated herbs aren't usually as potent or durable as extracts. In most cases, dried herbs lose potency faster than extracts—in months rather than years. But, air-dried herbs usually cost less than extracts or freeze-dried herbs, and can represent a good value—especially if you choose a reputable brand, purchase them well before the sell-by date, and consume them within a few weeks or months of purchase. Air-dried herbs are usually measured in milligrams of dried, ground herb per capsule. Some product labels also provide the percentage of active ingredients (e.g., "550 mg of ginger root per capsule, containing 1.5% essential oil").
Whole, air-dried herbs can be made into teas, used in cooking, or chopped finely and encapsulated. Herbal teas are ideal when an herb is intended for relief of respiratory and sinus symptoms (e.g., ginger, lemongrass), or is effective in a relatively dilute strength (e.g., chamomile, spearmint). Note: Herbal tea only provide the water-soluble compounds in herbs. Asian peoples often use dried medicinal herbs in cooking (e.g., astragalus, galanga, and shiitake )
Freeze-Dried Herbs
Freeze-dried herbs may contain the greatest amounts and range of plant chemicals. However, freeze-dried herbs are rare in the marketplace, and are relatively untested in clinical trials.
It is difficult for manufacturers to obtain steady supplies of fresh-harvested herbs, so they typically used dried herbs to make extracts. But certain active constituents of some plants are lost through air-drying. Freeze-drying preserves the active compounds in fresh herbs, while retaining their color, aroma and taste. (Research indicates that freeze-dried feverfew is as effective as fresh feverfew leaf for preventing migraine headaches, and that freeze-dried echinacea contains a broader range of active compounds than dried echinacea or alcohol-extracts of echinacea.) How does it work? Plants are picked at their peak, washed, flash-frozen, and dried at very low temperature in a vacuum chamber. Freeze-dried herbs are encapsulated for sale, or stored for later use to make extracts.
Extracts (liquid or dried)
Extracts are preferred for most uses, because solvents used (ethanol or glycerin) make available the maximum amount and range of chemical compounds. Herbal teas only provide the water-soluble compounds, and the body cannot effectively extract some active compounds from dried, encapsulated herbs. Extracts are also backed by more clinical research than air-dried or freeze-dried herbs. Alcohol and glycerin also preserve an herb's chemical constituents for two years or more.
Extracts can be made from fresh or dried herbs. Some herbs lose significant medicinal potency when dried, while others gain potency after drying. Reputable manufacturers (Gaia Herbs, Herb Pharm, Frontier, Zand, etc.) try to use the most potent form whenever possible.
Extracts fall into three basic categories:
- Guaranteed potency extracts (alcohol or glycerin) contain a minimum amount of an active compound, such as ginsenosides in Asian ginseng, or a minimum amount of a "marker" compound that merely confirms the identity of the source plant, such as parthenolides in feverfew. There are relatively few herbs whose medicinally active compounds have been clearly identified. And in many cases, an herb's beneficial effects depend on all its compounds acting together. The guaranteed potency declared on a product label—for example, "contains 3% ginsenosides" —indicates the minimum amount of active or marker compound found in it. The actual amount may be greater.
It is important to note that the presence of a specific amount of a certain compound cannot by itself guarantee efficacy. Look for products that offer a chemical fingerprint or "chemotype" that most closely matches the chemotype of the source plant. How can you know? At this point, consumers and retailer alike must rely largely on manufacturer's claims and reputation for integrity, as testing each extract would be prohibitively expensive. You can place greater faith in products analyzed using modern techniques such as HPLC (high pressure liquid chromatography), TLC (thin layer chromatography), MS (mass spectrometry), and NMR (nuclear magnetic resonance)—features we look for when choosing brands to offer.
- Standardized potency extracts (alcohol or glycerin) provide a specified, consistent level of one or more active compounds or "marker" compounds in the herb, with a very small range of variability. For example, the maker of one dried kava extract expresses the product's concentration/potency in three ways—the amount of extract per soft gel capsule (175 mg), the percentage of active compounds (kavalactones) in the extract (40%), and the amount of kavalactones per capsule (70 mg).
Standardization of an herb extract makes more sense when the specific chemicals responsible for an herb's therapeutic effects have been clearly identified—ginkgo and milk thistle are good examples. European physicians prescribe a standardized herbal extract when a patient needs a precise, rather than guaranteed minimum dose of a particular compound or compounds.
As with Guaranteed Potency products, it is wise to choose products that offer a chemical fingerprint or "chemotype" as close as possible to that of the source plant.
- Crude extracts (alcohol or glycerin) can be cheaper than guaranteed potency or standardized extracts, but just as potent and effective. Strength is expressed as a ratio of herb to solvent. For example, 1:2 means there is one gram of herb to two milliliters of solvent. The smaller the second number the stronger the extract. The term "tincture" is sometimes used interchangeably with "extract," but usually refers to a relatively weak homemade extract (1:5 is a typical strength).
The quality of an extract depends upon the medicinal quality of the source plant, which is affected by genetics, soil, climate, and the skill of the manufacturer. There is greater assurance of potency if you choose a crude extract from a highly reputable brand like Gaia, Zand, Herb Pharm, or Frontier.
Extracts: Which Dosage Forms are Best?
(Dried, Alcohol, Glycerin)
It is hard to say which of these three forms is superior. Many herbalists prefer liquid alcohol extracts, because their taste and smell may trigger important reactions in the body. But there is no proof liquids actually work better, and some consumers can't stand the taste of certain herb extracts.
Dried extracts avoid the taste issue, and will last longer. Glycerin extracts eliminate alcohol as an issue, but may not contain quite the range and quantity of active compounds found in an alcohol extract (liquid or dried). Any form of extract is acceptable, if it comes from a reputable manufacturer. With a little hunting, you can usually find crude, guaranteed potency, or standardized extracts in any of these three dosage forms.
- Encapsulated Dried Extracts are more stable than liquid extracts, and will preserve the potency of the active compounds for a longer period. They are made by vacuum distilling (removing) the alcohol from a liquid extract at very low heat, and/or "spray-drying" the liquid in large steel cylinders. Concentrations range upwards from 1:1. Dried extracts come in hard shell or soft gel capsules. "Solid" extracts are even more concentrated than regular dried extracts, and usually come as thick, resinous material in one-to-four ounce jars. Solid extract labels express concentration as a ratio of herb to finished product. For example, a concentration of 4:1 means that each gram of solid extract was made from four parts whole herb. The larger the first number, the more concentrated the product. Concentration ratios can range up to 100:1.
- Liquid Alcohol Extracts are the most common, usually packaged in one to four-ounce glass bottles with dropper tops. Many come in a concentration of 1:1 or 1:2, that is, one part herb to one or two parts alcohol. They are preferred by most herbalists, based on a traditional belief that part of body's response to herbs is related to tasting and smelling their constituents—a not unreasonable stance, given that the olfactory bulb is part of the brain. Alcohol extracts are used to produce solid and powdered extracts (see descriptions, below).
Many plants have compounds that are only extractable with alcohol, others by a mixture of water and alcohol. For many herbs, the best preparation and extraction methodologies are codified in the U.S. Pharmacopoeia and National Formulary. These considerations will affect the amount of alcohol contained in the finished product, unless the manufacturer has gone to the expense of evaporating some of it.
Note: You cannot effectively evaporate the alcohol from an extract by mixing the extract in hot water.
- Liquid Glycerin Extracts are offered for children, and for adults who do not wish to consume any alcohol. Like alcohol extracts, they are usually packaged in one to four-ounce glass bottles with dropper tops, and come in concentrations of 1:1 or 1:2.Glycerin, made from vegetable oils, has a naturally sweet taste, and extraction powers similar to alcohol's. (Depending on the herb, glycerin may not do as good a job of extracting certain active compounds.) Glycerin (trihydroxy alcohol) is metabolized in the body like a carbohydrate, is very easily digested, and has mild antibacterial qualities.