Milk Thistle Extract 70–80% Silymarin

The seed of Silybum marianum, which is the fruit of the plant, carries its flavonolignans in the seed coat, and that is the material behind this milk thistle extract. Ethanol extraction recovers them from the defatted seed, and the liquor is dried to a light yellow powder defined by its silymarin content.

The primary grade is 80% silymarin by UV, expressed as silybin, with a 70% grade as the lower end of the range. The powder is 80 mesh and insoluble in water. The 80% grade suits capsules and tablets with a small fill, and the 70% grade suits premixes in which a fuller extract profile is wanted.

SKU: BOT-STX-0011 Category: Standardized Extracts Tags: Ethanol Extracted, Flavonoids, Milk Thistle, Seed & Grain, Softgels & Oil Fills, Standardized Extracts

Silymarin Standardization & Grades

Silymarin is not one compound. It is a complex of flavonolignans, chiefly silybin, isosilybin, silychristin and silydianin, together with the flavonoid taxifolin. Silybin itself is a pair of diastereomers, silybin A and silybin B, and the names silymarin, silybin and silibinin are often mixed up in trade. A milk thistle extract is standardized to the whole silymarin complex because the members travel together through extraction and because the complex defines the botanical. Botanically the part sold as seed is an achene, a dry one-seeded fruit, and the trade uses the word seed for it. The percentage therefore describes the complex in the finished powder and says nothing about any single flavonolignan inside it. The entity is Silybum marianum (L.) Gaertn., and only the seed is used.

Grade	Assay & Method	Where It Fits
70% Silymarin	UV (expressed as silybin)	Premixes and softgel fills
80% Silymarin	UV (expressed as silybin)	Capsules and tablets with small fill

Grade choice follows fill weight, handling and cost. The 80% grade carries a little over 14% more silymarin per gram than the 70% grade, so the difference in capsule fill is small, and the choice is often decided by supply and by how the formula is written. The 70% grade brings slightly more of the non-silymarin fraction, which can improve compressibility. Milk thistle is also supplied as a 10:1 ratio extract with no marker figure, the Milk Thistle Extract Powder, as milled seed, the Milk Thistle Seed Powder, and as the purified compound Silybin (Silibinin) 98%.

Silymarin Analysis & Purity Risks

The UV method reads the sample against a silybin reference and expresses the total absorbing flavonolignan fraction as silybin. It counts the complex as a group and does not separate its members. HPLC separates silybin A, silybin B, isosilybin, silychristin and silydianin and adds them as individual peaks, which often gives a different total for the same lot. A UV figure expressed as silybin and an HPLC sum are therefore not interchangeable, and neither should be converted into the other.

Secondary markers sit beside the main complex. Taxifolin, the flavanonol that serves as a building block of the flavonolignans, and the fatty-acid residue of the seed are both watched. The pattern of the five flavonolignan peaks forms the fingerprint, and the proportion between silybin and the other members varies with the cultivar and the extraction route. This is why an identity check by chromatogram is useful on top of the single number.

Purity risks follow from the botany. The seed is oil-rich, and incompletely defatted material carries residual oil that dilutes the silymarin and gives a sticky powder. Silymarin concentrates in the seed coat, so a product from the whole plant differs from one made from seed. Look-alike thistles, such as blessed thistle (Cnicus benedictus), are different plants with different chemistry, and the CAS numbers for silymarin and silybin are often confused on trade sheets. The specification therefore ties the percentage to species, plant part and method.

Sample preparation also matters. Silymarin dissolves poorly in water, so the extract is dissolved in methanol or another organic solvent before reading, and the solution is kept from light. A reading taken from a solution that was not fully dissolved comes out low. For that reason a milk thistle extract figure should always be reported with its reference compound and its solvent, and a second laboratory should follow the same preparation before results are compared.

Typical Specifications

Specification Item	Product Information
Latin Name	Silybum marianum
Plant Part	Seed & Grain
Processing	Ethanol Extraction
Compound Class	Flavonoids, Polyphenols
Common Name	Milk Thistle
Ingredient Type	Standardized Extract
Marker Compound(s)	Silymarin (flavonolignan complex including silybin)
Primary Grade	80% Silymarin (UV, expressed as silybin)
Available Grades	70% · 80% Silymarin (UV, expressed as silybin)
Appearance	Light Yellow powder
Solubility / Dispersibility	Insoluble in Water
Quality Parameters
Moisture (LOD)	≤5.0%
Total Ash	≤5.0%
Particle Size	80 mesh
Heavy Metals	Lead ≤2 ppm · Arsenic ≤1 ppm · Cadmium ≤1 ppm · Mercury ≤0.1 ppm
Microbiology	TPC ≤1,000 cfu/g · Yeast & Mold ≤100 cfu/g · E. coli Negative · Salmonella Negative/25 g
Shelf Life	24 months in unopened original packaging, cool and dry storage

Applications by Grade

80% Grade for Compact Capsules

The 80% grade fills a capsule at a small weight and flows moderately well. The powder is fine and slightly static, so a glidant and a dry filling room keep the weight steady, and a clear capsule shows the pale yellow tone without adding color.

80% Grade in Tablet Blends

Tablets of the high grade need a dry binder and a lubricant, because the waxy seed residue can stick to punches. Run a compression trial on the full blend and check hardness after a week, since the powder draws a little moisture from the air.

80% Grade for Phospholipid Complexes

Silymarin barely dissolves in water, so formulators pair it with phospholipids or other carriers. The 80% grade keeps the inclusion in these complexes small, and the pre-blend is milled and dried before encapsulation to avoid lumps.

70% Grade for Softgel Suspensions

Softgel fills disperse the powder in oil with an emulsifier. The 70% grade suspends smoothly after milling, and settling should be checked before encapsulation, since the particles are insoluble and heavier than the oil phase.

70% Grade for Powder Premixes

Dry premixes for sticks and sachets take the lower grade at gram-level inclusion. The extract does not dissolve, so the cup is a suspension, and it belongs in opaque drinks or in mixes meant for shaking with a thickener.

Technical & Quality Considerations

The extract is a light yellow powder with a faint, slightly bitter taste and little aroma. It is practically insoluble in water and dissolves in acetone, methanol and ethanol, with limited solubility in oils. In water-based systems it forms a hazy suspension that settles quickly, so solid dosage forms and lipid carriers handle it more easily than clear drinks. The flavonolignans oxidize slowly in light and air, and silybin can isomerize in alkaline conditions, so the extract should be kept out of strongly basic bases.

For scale-up, sieve the powder, premix small inclusions in two steps with a dry carrier and check the fill weight at each lot change. Tablets need a hardness check after storage, and softgel suspensions need a settling test. Keep opened drums closed and shaded. Compare each lot with a retained sample for color and flow, and record the species, plant part and method on the batch record so the identity of the milk thistle extract is kept with the percentage.

Powder behavior deserves attention at the 80% grade. The fine particles are cohesive and tend to bridge in hoppers, so vibration or a screw feeder keeps the flow even, and a pre-blend with a flow agent at low inclusion avoids rat-holing. In dry premixes the pale yellow tone is easy to mask, but the insoluble fraction can leave a visible haze in water, which makes milk thistle extract a poor fit for clear drinks.

Packaging & Commercial Supply

Essencefield supports product evaluation, formulation trials, commercial orders, and ongoing ingredient supply. Packaging, storage, and shipping arrangements are determined by product characteristics, order quantity, stability requirements, and destination-market needs.

Supply Item	General Information
Sample	Available upon request for formulation, testing, and supplier evaluation
Order Quantities	100 g · 1 kg · 5 kg · 25 kg · 100 kg · 500 kg · Bulk
Sample Lead Time	Typically 5–7 days after sample confirmation
Production Lead Time	Typically 15–30 days after order and specification confirmation
Packaging	Suitable protective inner packaging with bags, cartons, drums, or other appropriate outer packaging
Storage	Store in tightly sealed, suitable protective packaging in a cool, dry environment. Protect from moisture, heat, and direct sunlight. Specific storage conditions follow the approved product specification.
Documentation	COA · Product Specification · TDS · SDS · Applicable declarations (as applicable)

Final order quantities, lead times, packaging, documentation, and shipping arrangements are confirmed according to the selected product and commercial requirements.