Q&A for Consumers: Hand Sanitizers and COVID-19 | FDA- percentage of alcohol for sanitizer ,If I add alcohol to non-alcohol hand sanitizer, will this be better to prevent COVID-19? A. No. Addition of alcohol to an existing non-alcohol hand sanitizer is unlikely to result in an effective ...Why 70% Isopropyl Alcohol Is a Better Disinfectant Than 99 ..."Isopropyl alcohol 99 percent is pure isopropanol and isopropyl alcohol 70 percent is pure isopropanol diluted with 30 percent purified water by volume," explains Dr. Lucky Sekhon, fertility specialist and board certified OBGYN in New York City."Isopropyl alcohol 70 percent, or isopropyl alcohol 99 percent diluted to 70 percent with purified water, kills organisms by denaturing their proteins.