As a result, HA represents the main circulating antioxidant system in the body. Sexually-Transmitted Diseases Patients should be counseled that this product does not protect against HIV infection (AIDS) and other sexually transmitted diseases. John’s wort may reduce the effectiveness of darunavir by increasing the breakdown of darunavir by the metabolic enzyme CYP3A This is so that if you need to change the dose after a routine blood test, you can do this the same day rather than waiting until the following morning.