As a result of these findings, Nonoxynol-9 became the ingredient of choice in many spermicidal products. The chemical also acts as a lubricant, an added benefit in the eyes of some users. However, additional research revealed that Nonoxynol-9 actually makes people more prone to infection because it can irritate mucus membranes, making it easier for bacteria and viruses to enter the body. In 2007, the United States Food and Drug Administration issued a warning about Nonoxynol-9, informing consumers that although the product is an effective spermicide, it does not protect against sexually transmitted infections, and can in fact increase the risk of transmission.