To date the only clinical proof of St. Jon's Wort's therapeutic efficacy has come from preparations that are standardised on hypericin. It is this compound that is used as the standardisation marker in Lamberts St Jogn's Wort. Each tablet supplies 1000µg hypericin. Most other one a day products supply just 900µg hypericin.
Please note: Patients taking any prescribed medicines should check with their pharmacist before taking St John's Wort as it may affect the way they work.