Determining Quality and Identity of Valerian Root Extracts

Neil Levin

Valerian Root Extract is often tested by using a “marker compound”, a substance that is detected in a product sample to prove the identity, but not the potency, of an herbal product. The distinction is that the actual “active ingredient” in an herb may not even be known,1 or there may be more than one active component, in which case detecting one or more marker compounds is the standard way to confirm the identity of the herb without providing any scientific information as to its actual potency or efficacy.

Like other herbal remedies, valerian root has many chemical components, but as states on its website, “it is not clear which of these are most important to its effectiveness…”2  We can see that an assay for valerian marker compounds is not a definitive test of actual potency or quality, as it does not quantify the admittedly-unknown active constituents.

Test results for liquid extracts may commonly contain only about half of the marker compound levels as dried extracts that are used in capsules. This is only common sense, as removing the liquid fraction (typically grain alcohol), which commonly comprises roughly 50% of the volume in a liquid extract, is necessary in order to produce a dried form of an herbal extract. The amount of alcohol in liquid extracts can vary, and sometimes the liquid extract is spray-dried onto a neutral carrier material such as starch, making comparisons with dried extracts less precise because of the natural variation in raw plant material and variations in the use of these processing aids and carriers.

The use of liquid herbal extracts is also significantly different than using a similar dried extract in a capsule. The same principles that allow our brain to identify molecules from smells or tastes, that in turn guide the body’s responses, apply to molecules in liquid extracts that are both inhaled and tasted. People that use liquid extracts do so because they understand that they are faster acting and have stronger effects than capsules, which makes sense due to the extra information that is imparted to the body from a substance signaling the brain via direct contact with sensors in the nose and mouth. This is the same principle as Aromatherapy, and the body routinely sends taste and scent signals from foods to the brain in order to trigger digestion.3-10

These points show that laboratory testing to determine the relative efficacy of different forms of valerian root supplements to be scientifically flawed, though the identity of the herb can be confirmed through the observation of known marker compounds called valerenic acids.

At NOW’s Quality Control lab, skilled analytical chemists tested samples of NOW's Valerian Liquid Extract, also sending a sample of the same lot to an independent lab for confirmation of the results. The valerenic acids were confirmed to be within a range of 0.35 to 0.41 mg per milliliter (mL), with the independent lab reporting slightly higher amounts than NOW’s own lab. Since the serving size is 2 mL, the amount of valerenic acid marker compounds found in this product would be in the range of 0.70 mg to 0.82 mg, per serving. By comparison, Consumerlab reports that a dried root powder of valerian should provide about 0.17% valerenic acids; an amount equivalent to 0.68 mg in a 400 mg capsule, which would provide about the same amount of marker compounds found in one serving of NOW's liquid extract. This is not to suggest that the two forms are equivalent, as dried valerian root would contain fiber and other inactive material that is not present in a liquid extract and the extract contains roughly 50% alcohol, which is not present in the dried root. A liquid can also work on different metabolic pathways than a capsule, as discussed earlier. An alcohol extract can also concentrate active material that is oil soluble, such as certain alkaloids, that tend to be naturally produced and concentrated in some herbal roots.

While these assays cannot determine the actual potency of any valerian product, they do give strong evidence that NOW Valerian Liquid Extract has been properly prepared from authentic, high-quality valerian roots, attesting to the overall quality of the finished product.


1 Herbal Medicine: Expanded Commission E Monographs, American Botanical Council, Published by Integrative Medicine Communications.


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