From the Manufacturer:
The first and only Cat's Claw product made exclusively from the root of the Uncaria tomentosa plant, where beneficial POAs are 200% more concentrated than in the bark.
Made from POA Cat's Claw, rigorously tested and verified by Immodal Pharmaka. This Cat's Claw affects your cellular immune system and supports the body's ability to produce the optimal level of immune activity.
(POA is short for pentacyclic oxindole alkaloids).
Standardized to be free of harmful levels of certain substances commonly found in traditional Cat's Claw.