SDG Lignan Standardization & Grades
SDG is secoisolariciresinol diglucoside, the main lignan of flaxseed. In the seed it does not occur free: it is held in an ester-linked macromolecule with hydroxymethylglutaric acid and with ferulic and coumaric acid glycosides, and an alkaline hydrolysis step releases it for measurement. The botanical entity is Linum usitatissimum L., and the extract is standardized to SDG, with total lignans as the related basis, because SDG is the defining lignan of flax and the compound that HPLC measures cleanly after hydrolysis.
| Grade | Assay & Method | Where It Fits |
|---|---|---|
| 10% SDG Lignans | HPLC | Drink powders and bar blends |
| 60% SDG Lignans | HPLC | Capsules and tablets, small fill weight |
Grade choice follows dose and fill weight. The 60% grade carries six times the SDG of the 10% grade per gram, so a capsule reaches its target with a fraction of the powder, while the 10% grade is bulkier, lighter in flavor and easier to dissolve in a beverage. Flax is also supplied as a 10:1 ratio extract with no marker figure, the Flaxseed Extract Powder, as milled seed, the Flaxseed Powder, and as a single compound, Secoisolariciresinol Diglucoside (SDG) 95%. The standardized extract is the row to use when an SDG figure has to appear in the specification of the flaxseed extract.












