high strength extract standardised at 3% rosavins, correct dose and species of rhodiola , perfect partner to siberian ginseng, magasorb and theanine ,excellent value for uk-made taste free, coated tabletsnature\'s best rhodiola is a premium, high strength extract equivalent to 500mg of dried rhodiola rosea, obtained from the rhizome and root of the herb. standardised to ensure that it contains exactly what the label states, 2 tablets provides a guaranteed 3.75mg (3%) of precious rosavins, the \'active\' compounds found in the herb and referred to in studies. in the course of developing our product we tested a number of raw materials available and determined that the few claiming to contain higher percentages than 3% often did not. the raw material we use is specifically tested for its rosavin level and reassuringly, we screen all herbal materials to ensure none have been irradiated. rhodiola rosea has been used for centuries and it makes the perfect partner to siberian ginseng, magasorb® and our theanine/lemon balm supplement!