Extract Ratios Explained

An extract ratio such as "10:1" tells you how much plant material was used to make a given amount of extract. On its own it does not tell you how strong, pure or useful the extract is. A review of the topic says these ratios "can be misleading" when people do not understand what they mean. [1] The idea applies to any botanical extract, including extracts of adaptogen plants such as ashwagandha (Withania somnifera; supplements typically contain root, leaf or root-and-leaf extracts) and rhodiola (Rhodiola rosea; the root and rhizome are the parts used in EU herbal medicines). [2][3][4] Note that "adaptogen" is a contested label, and nothing on this page says an extract works.

What the ratio means

A plant-to-extract ratio compares the amount of plant used with the amount of extract that came out. [1] The European Medicines Agency (EMA) calls this the DER, short for drug-to-extract ratio, and its guidance applies it to the "genuine" (native) extract, meaning the extract before any carrier or filler is added. [1]

The review gives a plain example: a dry extract with a native ratio of 10:1 means that about 10 g of dried raw material were needed to make 1 g of native extract. [1] The review also says that crude extracts without added excipients are called native or genuine extracts, and that excipients are often added later to improve handling or to adjust the concentration of certain compounds. [1]

The ratio can be a range, not one number

Real batches vary. The review gives an example in which one 100-kg lot of plant material yields 14 kg of native extract and another lot, made the same way, yields only 11 kg, so the honest ratio is a range (7-9:1). [1]

A higher number is not a stronger extract

The review calls the idea that a higher ratio means a stronger, better extract "perhaps the most common misconception." [1] Its reasoning:

• A ratio describes the yield from a given raw material using a given process. [1]
• For most dry plant material extracted with water or water-and-alcohol, the soluble part is usually between 10 and 25 percent of the plant, which works out to ratios of roughly 10:1 down to 4:1. [1]
• Woody roots may hold little extractable material, so they can give high ratios even when extracted thoroughly. [1]
• A high ratio can reflect a targeted extraction, but Australia's TGA is quoted as saying it may also simply reflect a partial extraction. [1]

The review uses two adaptogen plants as examples. Using minimum extractive values from Hong Kong's Chinese Materia Medica Standards, it works out a theoretical ratio of about 33:1 for eleuthero root (Eleutherococcus senticosus) and about 4:1 for Asian ginseng root (Panax ginseng). [1] In other words, two different plants can have very different "normal" ratios, so a ratio cannot be compared across plants. The review also notes that ginsenoside levels differ between parts of the ginseng root, which changes the ratio needed to reach the same marker level. [1]

What a ratio does not tell you

Why this matters for trial results

Trials of ashwagandha, rhodiola and ginseng use specific extracts, and results for one extract do not transfer to another. NIH's National Center for Complementary and Integrative Health notes that supplements bought in stores or online may differ in important ways from the products tested in studies. [7] A matching ratio on a label does not show that a product matches a trial extract. For the markers that trials report, see Standardization and marker compounds; for amounts that were used in trials, see what clinical studies say about amounts.