About Long Nails Long nails on women are considered sexy by many people, but there is caution. According to a study done by Shelly McNeil, M.D., an infectious-disease specialist at Dalhousie University in Halifax, Nova Scotia, nails longer than three centimeters (just a bit over one inch) are five times more likely than trimmed nails to carry the pesky pathogens that cause staph and yeast infections. To be on the safe side, Dr. McNeil warns that you need to be diligent about washing your hands (especially after contact with such germ-prone items as doorknobs, public toilets and gym equipment). You also might want to carry an alcohol-based hand gel that can be used to disinfect your hands when soap and water aren't available. Note: Acrylics and other falsies can carry more harmful bacteria and are more difficult to disinfect.