In the lab, studies have demonstrated quercetin’s antiviral effect against both herpes simplex virus type 1 (HSV-1) and 2 (HSV-2). Quercetin extracted from apples inhibited both HSV-1 and HSV-2 replication by greater than 50%.75
One doctor recommends taking 500 mg of quercetin three times a day as a treatment for shingles (herpes zoster), an often painful condition caused by reactivation of dormant varicella-zoster—the same virus that causes chicken pox.76