The extraction solvent decides what comes out of the plant. The carrier is what goes into the powder besides the extract.
Two short lines of a botanical extract specification are easy to pass over: the extraction solvent and the carrier. The first describes how the extract was made. The second describes what the powder contains apart from the extract. Both matter for the rules your product has to meet and for what goes on its label.
Here are six checks to make on these two lines, with the definitions regulators use, the food rules of the European Union and England, and the labelling rule of the United States. The example comes from our own catalogue. Our earlier articles covered the specification, the extract ratio and the Certificate of Analysis; this one stays with the solvent and the carrier.
01 / THE SOLVENT LINE
What does the solvent line state?
The solvent line names the liquid the plant material was extracted with, and its strength. European medicines guidance asks that “the name and composition of the solvent(s) used in the first extraction step” be included in the declaration of a herbal medicine, and its examples show the form: “Extraction solvent: Ethanol 70 % V/V”, or “First extraction solvent: Acetone 60 % m/m”.1 A companion guideline requires the nature and concentration of any extraction solvent or solvent mixture to be indicated.2
Read the figure with its unit. Ethanol 70% V/V is a mixture of ethanol and water with 70 parts of ethanol in 100 parts by volume; m/m means parts by mass. A water extract, a 70% ethanol extract and a 96% ethanol extract of the same plant are three different materials, because each solvent dissolves a different share of what the plant contains.
Check: the name of each solvent, its strength, and whether the strength is given by volume or by mass.
02 / LATER STEPS
Was any other solvent used after the first step?
What the guidance asks to be declared is the solvent of the first extraction step.1 An extract may then be concentrated, purified or divided into fractions, and those steps can use other liquids. The same guidance adds the word “refined” to the name of a preparation that has been purified,1 and the international guideline on residual solvents counts as likely to be present both “the solvent used in the final manufacturing step” and solvents from earlier steps that are “not removed consistently by a validated process”.5
Solvent may also be recovered and used again. European guidance on herbal medicines says of this practice: “Any use of recovered/recycled solvent should be justified”.2 If your quality system has a position on purification solvents or on recycled solvent, raise it before you order.
Check: whether the extract was purified or divided into fractions after the first extraction, which solvents those steps used, and whether solvent is recovered and reused.
03 / FOOD RULES
Is the solvent permitted for your product?
In the European Union, the list of extraction solvents for foods is closed. The law defines an extraction solvent as one “which is removed but which may result in the unintentional, but technically unavoidable, presence of residues or derivatives in the foodstuff or food ingredient”. It authorises water, to which substances regulating acidity or alkalinity may have been added, and “other food substances which possess solvent properties”, and it lists seven solvents for all uses: propane, butane, ethyl acetate, ethanol, carbon dioxide, acetone and nitrous oxide.3
Two more, methanol and propan-2-ol, are listed for all uses with a maximum residue of 10 mg/kg in the extracted food or ingredient. Others are listed only for named uses: hexane, for example, for producing fats and oils, defatted protein products and defatted cereal germs, and for preparing flavourings. Member States “shall not authorise the use of other substances and materials as extraction solvents”.3 The regulations for England carry the same seven solvents and the same 10 mg/kg limits, and forbid the use in food production of any extraction solvent that is not permitted.4
These lists apply to foodstuffs and food ingredients. A medicine is assessed under different rules, as the next check shows.
Check: that every solvent used is permitted for foods in your destination market, and for the kind of product you make.
04 / THE RESIDUE
How much solvent may remain?
Extraction solvents are removed, but not always completely. For the seven solvents listed for all uses, European Union food law sets no figure: their use must leave only “residues or derivatives in technically unavoidable quantities presenting no danger to human health”. For the others it sets figures, such as the 10 mg/kg for methanol and propan-2-ol.3
Guidance for medicines works differently. It sorts solvents into three classes: “Solvents to be avoided”, “Solvents to be limited” and “Solvents with low toxic potential”. Ethanol, acetone and ethyl acetate are in the third class, for which up to 5000 ppm, or 0.5%, “would be acceptable without justification”; methanol and hexane are in the second, with concentration limits of 3000 ppm and 290 ppm.5
The two systems can give very different answers for one solvent: 10 mg/kg for methanol in a food ingredient in the European Union, 3000 ppm in the medicines guideline, three hundred times as much. So a residual solvent row tells you little until you know which rule its limit was taken from. The row should also name the solvent that was tested for and the method, typically gas chromatography.5
Check: which solvents the residue row names, the limit and its unit, and whether the limit comes from food law in your market or from a medicines guideline.
05 / THE CARRIER LINE
What is in the powder besides the extract?
Many dry extracts contain a second material. European medicines guidance separates two kinds of addition: excipients for adjustment, which bring a standardised extract to its declared content, and other excipients, “technological excipients (e.g. carrier substances) which may be part of herbal preparations”. The native extract is “the preparation without excipients”.1 For extracts that are not standardised in that sense, the companion guideline allows excipients “for technological reasons only”, for example “to improve flowability, compressibility or solubility of the extract”, and says their content “must be stated as a fixed percentage”.2
Food law has its own description of what a carrier does. In the list of functional classes in the European Union’s regulation on food additives, which reads the same in Great Britain, carriers are “substances used to dissolve, dilute, disperse or otherwise physically modify” an additive, a nutrient or another substance added to a food, “in order to facilitate its handling, application or use”.6
Our Bamboo Extract shows how such a line reads. The documented grade is standardised to at least 75.0% silicon dioxide (SiO₂), measured by ICP-OES; it uses a maltodextrin carrier and is highly dispersible in water. The questions for any carrier are what it is, how much of the powder it makes up, and whether the figures on the specification refer to the powder as supplied. Our article on extract ratios shows how far a ratio moves when the carrier is counted.
Check: what the carrier is, its percentage, why it is there, and whether the assay and the ratio refer to the powder as supplied.
06 / YOUR LABEL
What do the two lines mean for your own label?
The carrier changes the arithmetic of a dose. In the European guidance’s example, a capsule holds 200 mg of a dry extract that is 80% native extract and 20% other excipients, and the declaration reads 160 mg of extract.1 If you calculate a dose from the weight of the powder, you need the carrier percentage.
Labelling rules ask about both lines. In the United States, where a dietary ingredient is an extract from which the solvent has been removed, “the weight of the ingredient shall be the weight of the dried extract”. For a liquid extract the solvent appears on the label: “Where the name of the solvent used is not included in the nutrition label, it is required to be listed in the ingredient statement”. And ingredients that are not dietary ingredients, “such as excipients, fillers, artificial colors, artificial sweeteners, flavors, or binders, shall be included in the ingredient list”.7
Rules for ingredient lists differ from market to market, and this article does not cover them all. In each of them you need the name and the share of the carrier to write your own label.
Check: the amount of extract without carrier in your dose, the name of the carrier for your ingredient list, and the solvent wherever your label must name it.
WHAT TO SEND
Ask about the solvent and the carrier with your enquiry
When the solvent or the carrier matters to your product, tell us:
- the ingredient, and the plant part if more than one is offered;
- the extraction solvent or method, if your product requires a particular one;
- any carrier, solubility or other technical requirements;
- solvents or carriers your product must not contain;
- the residual solvent limits your quality team applies, and the rule they come from;
- your intended application and destination market;
- your name, company and contact details.
Customisation can include concentration, extract ratio, target active-compound levels, extraction options and carrier or solubility requirements. You can discuss water, ethanol or solvent-free extraction options and carrier selection with us; feasibility is reviewed for the selected ingredient and project. Specification ranges in our catalogue are references, and feasibility, availability and price are confirmed with your quotation.
The product example is taken from the YOHOLIFE® catalogue; confirm the selected grade, its extraction solvent and its carrier when enquiring. Sources 1, 2 and 5 were written for medicines and are cited here for their definitions and limits; sources 3, 4 and 6 are food law; source 7 is the United States labelling rule for dietary supplements. Legal references were checked on 12 November 2026 and are given for orientation, not as regulatory advice.
