Milk thistle extract is a dry, light-coloured powder that is easy to encapsulate. The hard parts are elsewhere. Silymarin is poorly soluble and poorly absorbed, and the percentage on the certificate depends on the assay method. Both affect what you can put on the label.
Solubility and Absorption
Silymarin is a mixture of flavonolignans: silybin (silibinin), silychristin, silydianin and others. It dissolves poorly in water. Javed and colleagues (Alternative Medicine Review, 2011) describes poor absorption, rapid metabolism and low oral bioavailability. The review also lists the techniques used to improve it, from cyclodextrin complexes to phytosomes.
Kidd and Head (Alternative Medicine Review, 2005) describes the silybin–phosphatidylcholine complex. If your concept depends on an enhanced form, specify it as a separate ingredient with its own data. Do not assume a standard extract behaves like one.
Capsules and Tablets
Standard silymarin extract suits capsules and tablets. Fill weight follows from the grade. At 80% silymarin, 175 mg of silymarin needs about 220 mg of extract, which leaves room for other actives in a size 0 capsule. At 70%, the same silymarin needs 250 mg.
The extract is often slightly hygroscopic. Keep it sealed, and check flow and weight variation on your filler.
Drinks and Powders
Standard extract does not dissolve in drinks. For beverage or powder concepts, ask about water-dispersible or organic grades, which we supply on request. Then test sedimentation and taste in the full recipe.
Match the Label to the Assay
UV and HPLC report silymarin on different bases. A UV figure counts everything that absorbs at the test wavelength. HPLC measures individual flavonolignans. The same lot can give two different numbers.
State the method next to the percentage in your specification and on supplier certificates. Our stock grade is 80% silymarin by UV with HPLC identity. Silibinin by HPLC is available per batch for labels that follow a monograph. See silymarin: UV vs HPLC.
Choosing the Grade
| Grade | Typical use |
|---|---|
| Silymarin 80% (UV, HPLC identity) | Premium capsules and tablets |
| Silymarin 70% (UV) | Mainstream capsules and tablets |
| Silymarin 65% (UV) | Cost-sensitive and blended formulas |
| Silibinin by HPLC (on request) | Monograph-matched labels |
| Organic or water-dispersible (on request) | Organic lines and beverages |
Grades and documents are on the milk thistle extract page. For dose ranges see the silymarin dosage guide.
Silymarin with the method stated
Tell us the grade, the format and the label basis you need. We send the specification and a reference certificate.