Rhodiola extract 500 mg from Vitortho contains 15 mg of rosavine (3% of 500 mg) per capsule. The amount of salidroside is not known.

The Rhodiola Root Extract contains at least 7.5 mg of rosavine and 2.5 mg of salidroside per capsule.

It is quite possible that the Rhodiola extract from Vitortho also contains 2.5 mg of salidroside per capsule, or even 5 mg, but no data is available on this.

Regarding the Rhodiola rosea 1000 mg from Lamberts (actually 250 mg of a 4:1 dry extract), it contains 8 mg of rosavine per tablet, which is only half a milligram more than Solgar's formula. The amount of salidroside is also unknown for this product.

Per capsule, the Rhodiola from Vitortho has the highest dose of rosavine (15 mg), followed by Lamberts (8 mg) and Solgar (7.5 mg).

Both Lamberts and Vitortho are excellent manufacturers. Solgar has an excellent reputation, but when it comes to herbal formulas, other manufacturers are often just as good and may offer a better price/quality ratio.