1-Docosanol

1-Docosanol, also known as behenyl alcohol, is a saturated fatty alcohol with 22 carbon atoms. It has long been used in cosmetics as an emollient, emulsifier and thickener, and it later became a medicine. In July 2000 it was approved for medical use in the United States as an antiviral agent that reduces the duration of cold sores, and it is sold over the counter, most widely under the brand name Abreva. It is applied as a cream. Docosanol is thought to work by stabilizing the surface phospholipids of the host cell, which prevents the herpes virus envelope from fusing with the cell membrane and so blocks entry and replication. The most commonly reported side effect is mild headache, which occurred about as often with placebo in clinical trials, and rare allergic reactions have been described. A placebo-controlled trial found an average shortening of healing of 17.5 hours, and in 2007 a US class-action suit over the claim that it cut recovery time in half was settled.