Although the FDA acknowledges the benefits of Trametes veriscolor , one of the main reasons why they can't legally approve extracts of coriolus, like PSK, is because the API (active principal ingredient) needs to be precisely identified. According to Paul Stamets, "PSK is an assortment of sugars and attached proteins but has no unique molecule responsible for its impact on the immune system. Without that API, verification from batch-to-batch is not possible. Thus, it is classified as an undefined drug. This is one reason why PSK cannot be legally imported nor marketed in the United States."
Disclaimer: The entire contents of this website are based upon the opinions of Dr. Mercola, unless otherwise noted. Individual articles are based upon the opinions of the respective author, who retains copyright as marked. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the research and experience of Dr. Mercola and his community. Dr. Mercola encourages you to make your own health care decisions based upon your research and in partnership with a qualified health care professional. If you are pregnant, nursing, taking medication, or have a medical condition, consult your health care professional before using products based on this content.