Are You Under-Prescribing Extract Powders?

Although it’s been several years since I first wrote about extract powders and granules, I want to follow up on that article, as promised, with a discussion about dosages and prescribing guidance. I strongly suggest (re)reading that article since it provides a foundational knowledge of these popular products. In that article, I defined the difference between extract powders and extract granules, whether extract powders/granules are truly concentrated (or not), what the designation 5:1 means when referring to extract powders/granules (it’s the yield ratio, not the concentration), various factors that affect yield, and how excipients/fillers/diluents are used to improve yield.

One of the common questions to our consultants from clinicians is regarding the recommended dosages for our extract powder formulas and single herbs. What is the extract powder dosage equivalent of single herb compared to a raw herb (or formula)? After several discussions with our manufacturers and other experts in the production of extract powders/granules, I regret to report that there is no bona fide equivalency. In addition, in the case of extract powders and granules, and indeed across all dosage forms, the expression, “you’re comparing apples to oranges” applies. The various methods of herbal prescribing, extract powders and granules, draughts, decoctions, pills, tablets, tinctures, etc., feature dosages which are all over the place and do not lend themselves to any easy calculation of raw herb equivalency, in any sense. Mostly, clinicians must depend on their herbal training and experience and, in large part, the dosage recommendations of the manufacturer of the herbal formula product to determine a therapeutic dose. Regardless of the form of administration, the clinician is expected to adjust dosages based on several factors, most of which were clearly described in Laura Stropes’ article in the March 2018 newsletter.

Dried Optimized Decoctions

Extract powders and extract granules are two very similar products. Both begin with a formula comprised of raw (bulk) herbs that are decocted in an aqueous solution, using modern equipment, including pressurized, temperature-gradient cookers with volatile component recovery systems. The resultant liquid is condensed under low heat using vacuum evaporators to a thick syrup. The next step is where these two products differ. In an extract powder system, the condensed liquid is spray-dried into a powder. The main advantage of the resultant powder is that it does not require the addition of excipients before use. The one drawback to an extract powder product is that it is hygroscopic, which means that it readily absorbs moisture, even from the atmosphere. If spray dried powders are left open to air, they may form clumps in the powder, which is one of the reasons that some manufacturers add carriers. To obviate the need of adding such a diluent, Plum Flower® formula extract powders are packaged with a desiccant and a moisture-proof seal. In most cases, this hygroscopy is not a problem with herbal formulas since a 100 g bottle of an extract powder formulas, at normal doses, is customarily consumed in 7 to 12 days.

In an extract granule system, the condensed liquid is sprayed as an aerosol onto a carrier (excipient), usually in either a starch, dextrin, or maltodextrin. The resultant particles are sieved to achieve a uniform size. This form of wet-granulation is called flow-coating and it is the most commonly used to create extract granules, although there are alternate methods of creating granules. According to the Pharmacopeia of the People’s Republic of China, granule products contain at least 20% excipient to a maximum of 60%.

The powder from an extract powder product is 100% of the dissolved solids in the original aqueous decoction. This is a significant advantage of extract powders. There are no carriers (diluents) added to an extract powder. This means that compared to an extract granule product, an extract powder contains more of the original dried solids from the decoction, gram for gram. However, because single herbs are often opened and closed numerous times over a potentially lengthy period of time before a 100 g bottle would be completely consumed, Plum Flower® single-herb dried decoctions are produced in extract powder form with the additional of a minimal amount of excipients to prevent clumping.

Concentrate versus Concentrated

When deciding about dosages for dried decoctions, one must confront what the designation 5:1 means when referring to extract powders/granules. Although I discussed this extensively in Part One, it’s important to review this issue. 5:1 is the yield ratio, which expresses the weight of dissolved solids extracted and dried from the original decoction, including added excipients, versus the weight of the raw materials that were used to create the extraction. It is not the degree to which it is concentrated. Concentrated herbal products would be better expressed in terms of a factor, such as 2X, 3X, or 5X. For example, if a formula calls for 75 g of herbs cooked in 4 cups of water, one could create a 2X concentrated formula by using 150 g of herbs cooked in 4 cups of water. This formula would be twice as strong as the original formula. There is a diminishing return for this process due to the physics of solutions and it is quite difficult to even achieve a 4X concentration.

Thus, I want to make a distinction between something that is concentrated (4X) and a concentrate (4:1), which is a better way of understanding these products that are made from dried decoctions. A concentrate is a form of substance which has had the majority of the solvent removed. Typically, this is the removal of water. Think of frozen orange juice concentrate. Usually, the concentrate is re-constituted at the time of usage by the addition of the water. Herbal extract powders/granules are concentrates because the liquid solvent (water) has been removed. They can be re-constituted by dissolving the powder/granules in water. This is the most common way, at least in the U.S., that extract powders are consumed by patients, i.e. adding water to reconstitute and then drinking as a “tea”. (Of course, some patients prefer these powders/granules to be placed into capsules, and some hardy souls simply place the powder/granules on their tongues.) Now, imagine a 4X orange juice product that has four times the amount of orange juice solids in the beverage. While it will have 4 times as much vitamin C as normal orange juice, it might not be as popular a breakfast drink as it is now, because it would seem thick and overly sweet.

Although 5:1 is sometimes called the “industry standard”, the yields of herbs and herbal formulas are often below or above this 5:1 standard. For example, an analysis of 71 Plum Flower® formula extract powders from a report from our manufacturer, demonstrated a mean yield ratio of 5.88:1 (± 2.44) and the median was 5.12:1. The range, however, was 2.88- 14.81:1! Keep in mind that the numerator in this ratio indicates the amount of raw material needed to make the denominator. Thus, a 7:1 yield ratio represents a poorer extraction than a 5:1, and a 3:1 yield ratio means that more material was extracted from the raw material than in a 5:1 product. There are various factors that affect yield including the quality of the herbs that are used, and how much can be extracted from a particular herb in the first place, and I refer you to Part One for the complete discussion. A final point to consider is that not only are different herbal formulas going to provide different yield ratios, the yield ratio of a particular herb or formula is going to vary batch to batch. In order to avoid having to disclose production yields for every formula and every batch, manufacturers prefer to refer to the industry standard, that is 5:1, even though this is misleading. And, there is marketing. Some companies imply that 7:1 is “better” than 5:1, when in fact, the opposite is the case.

History and Evolution of the Use of Decocted Extract Powders

In researching published data for this article regarding dosages for our extract powders/granules, I discovered some interesting information. Several manufacturers do not state on their website what their recommended dosage for these products is. Otherwise, various authors recommend a wide range of dosages.

In Japan, extract granules developed into an important part of Kampo medicine in the 1950s. Kampo is based on ancient Chinese herbal formulas, especially those from the Shanghan Lun (Han Dynasty) and Hejiju Fang (Song Dynasty). Kampo formulas are often composed of 4 to 9 herbs and dosages were usually relatively small (for many theoretical reasons): between 2 to 6 g per day.

A short time later, Taiwan began using extract granules instead of home-prepared decoctions, mostly because of their convenience for patients. However, in Taiwan, in keeping with the development of the use of Chinese herbal formulas during the Yuan, Ming, and Qing dynasties, the formulas contained a larger number of herbs and the dosages prescribed were often three times higher than those in Japan. Depending on the formula, dosages were often 12 to 18 g per day. It is reported that the national health service in Taiwan will pay for up to 24 g per day.

When extract granules first appeared in the United States in the late 70s and early 80s, most companies recommended a dosage of 6 g a day. Today, various sources suggest a range of dosages from 3 g to 18 g per day. Generally, larger dosages are associated with acute conditions and smaller doses are associated with chronic conditions, especially when deficiency is involved, and long-term therapy is indicated. Other considerations include the size of the original formula in terms of the number of the herbs or total grams and not surprisingly, the actual yield ratio of the formula. Formulas with “higher” yield ratios, for example 7:1, may require a higher dose. Just as Laura Stropes pointed out in her article last March, one truly has to rely on one’s clinical experience. Of note, the published standard dose for Mayway extract powders (which contain no excipients) is 3 g, three times per day or 4-5 g, twice a day.

An Example


Let’s look at an example of recommended dosages for the classic formula for kidney yin deficiency Liu Wei Di Huang Wan (Tang), according to Bensky’s Formulas and Strategies:

Herb Grams
Shu di Huang 24
Shan Yao 12
Shan Zhu Yu 12
Fu Ling 9
Mu Dan Pi 9
Zie Xie 9
Total 75g per day in a decoction

Plum Flower® Liu Wei Di Huang San (100% extract powder) composition (note that this is the same composition as the textbook formula above):

Herb Percentage
Shu di Huang 32
Shan Yao 16
Shan Zhu Yu 16
Fu Ling 8
Mu Dan Pi 8
Zie Xie 8

These percentages represent the percentage amount of the herbs in 1 g, 6 g, 75 g, or 100 g, regardless.

Using Mayway’s dosing guidance, if one wanted to dispense a weeks-worth of this formula at 4 g twice a day, this would make a total of 57 g (rounded up) to be dispensed.

Using other companies’ extract granules and remembering that about one third of their extract granules is excipient, one would need to dispense 84 g, and do be taken as 6 g twice a day to achieve an equivalent dose to Mayway’s extract powder at the dose given.

Since extract powders/granules are dried decoctions, one interesting idea to try is to check the consistency of a single dose in a cup of water and compare that to a decoction made from raw herbs. If the “tea” appears to be “thin” (in color or taste), then this is probably not an effective dose when compared to a raw herbs decoction. Again, referring to orange juice concentrate, one can readily tell “weak“ orange juice or if it’s been appropriately diluted with water; it’s the same with dried decoctions. Of course, the correct dosage of extract powders/granules relies entirely on one’s clinical judgment.

Tailoring

In many ways, so far, this has been fairly straightforward. Now let’s look at tailoring classic formulas with single herb extract granules. This is quite a bit more complicated. There are a couple of issues that need to be considered. First, the little spoon that is dispensed with these formulas, sometimes called a “gram spoon”, is not necessarily equivalent to a gram (even though, for patients, it has great practicality). Really, it depends on the density of the extract powder or granule product. In the dispensary, a scale capable of accurately measuring grams is required. The second issue also relates to densities and granule size. Ideally, every dose of the finished product would be the same as every other dose. This requires significant mixing. Most dispensaries, whether in a practitioner’s office for a school of TCM are not equipped with a mixer capable of performing this task. It is not sufficient to stir the extract powder/granule mixture in a bowl with a spoon or to shake it in a bottle and call that “mixed”. In Mayway’s GMP-compliant dispensary, we use a Turbula®, a professional mixer to mix each tailored formula for at least 10 minutes.

In general, I have observed that nearly everyone adds single herbs to a tailored formula at far too low a dose. I’ve noticed that most clinicians when adding a single herb to a formula that they usually add 2 or 3 g, sometimes as much as 5 g, and rarely more than that.

Let’s look again at Plum Flower® Liu Wei Di Huang San (100% extract powder):

Herb Percentage g in 57g
Shu di Huang 32 18
Shan Yao 16 9
Shan Zhu Yu 16 9
Fu Ling 8 7
Mu Dan Pi 8 7
Zie Xie 8 7

Now suppose I want to add two herbs that supplement the Liver and Kidney yin and cool the Blood. For example, Han Lian Cao and Nu Zhen Zi. This herb couple is often added to a decoction at 9 g each in each bag of herbs. I look at the original formula and notice that three of the herbs in the original decoction are also dosed at 9 g per bag (otherwise, I would calculate what % of the total formula 9 g would represent). These three herbs appear in our weeks-worth of extract powder as 8% of the total formula and 7 g in 56 g for the week. Therefore, I would first consider adding 7 g of both Han Lian Cao and Nu Zhen Zi to the formula, but since the Plum Flower® single herb extract powders contain dextrin, I have to adjust my dosage to account for the excipients (since the formula extract powder does not contain excipients) to maintain the correct balance in the formula. Like all single herbs and formulas in extract granule form, each herb and formula will have a different amount of excipient depending on production requirements. Since I do not know the amount of excipients in each herb batch, I’m going to assume that the amount of excipient equals 30%. This means, to keep the formula balanced, I will need to add 10 g of each of the single herbs that I am adding to the extract powder formula. This results in a total formula of 77 g and my new dosage will be 5.5 g twice a day. (In practice, I probably would tell my patients to use 5 slightly heaping gram-spoons per dose.)

I trust this has been helpful; it’s obviously more complicated than one would think at first glance, but it provides you with a good place to start. In an ideal world the production yield ratio, that is 5:1, would be relevant, but it is not. Finally, I want to reemphasize that there is no quick and easy equivalency between dried decoctions, whether extract powders or extract granules, and the raw herb prescribing that we were taught in acupuncture school. There is a learning curve, but with a little thinking (and math) these products can be extremely valuable for both clinicians and patients.

RESOURCES

In addition to the author’s experience and interviews, the following resources were consulted:

 

Bio: Skye Sturgeon, DAOM, L.Ac.

Skye is the Quality Assurance Manager and Special Consultant for Mayway, USA. Skye was the former Chair of Acupuncture & East Asian Medicine and core faculty member at Bastyr University, core faculty member and Faculty Council Chair at the American College of Traditional Chinese Medicine, and President and Senior Professor of the Acupuncture & Integrative Medicine College, Berkeley. Before making Chinese medicine his career choice, Skye held various positions in the Natural Foods Industry for 12 years and prior to that was a clinical biochemist and toxicologist.

 

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