70% and 96% alcohol are regularly sold as common disinfectants in homes and workplaces, especially during a health pandemic. Both antiseptics have shown effectiveness against bacteria and viruses. What are the differences? Here we explain it to you.
Differences between 70% and 96% alcohol
According to Nuria Salazar Sánchez, professor of Pharmacy and Pharmaceutical Technology at the CEU San Pablo University, 96% alcohol is the most concentrated compared to its counterpart, while 70% alcohol is more diluted (70% ethanol and 30% water).
However, they are authorized as antiseptics for healthy skin. However, their use on open wounds would be misused, according to Joaquina Huarte, second vice president of the Spanish Society of Clinical, Family and Community Pharmacy (SEFAC).
"It should not be used for this purpose, as it is very irritating and in contact with organic matter it could coagulate proteins, thus facilitating the survival of some bacteria," commented the pharmacist. Highlighting that only in such cases, the use of chlorhexidine or iodized alcohol is recommended.
Why is 70% alcohol better than 96%?
This is a common belief, since 96% alcohol would be more effective against viruses and bacteria due to its concentration. However, 70% alcohol would have the highest bactericidal effectiveness; it is capable of eliminating up to 90% of bacteria on the skin.
On the other hand, 96% alcohol would only manage to eliminate 75% of bacteria, in addition, it has the ability to evaporate quickly and would not have enough time to disinfect, unlike 70% alcohol.
Which alcohol is better against the coronavirus?
According to pharmacists, 70% and 96% alcohol are useful tools for hygiene and disinfection when it is not possible to wash hands with soap and water to remove traces of the coronavirus.
"For a hydroalcoholic gel to have virucidal activity, alcohol must be present in the formula at a concentration between 60% and 95%," commented the specialist from the CEU San Pablo University, so a concentration of 70% would be optimal.
It was determined that the use of 90% alcohol is more concentrated, "but less effective for hand hygiene and antiseptic," indicated the General Directorate of Medicines, Supplies and Drugs (Digemid). "This alcohol will evaporate very easily, therefore, the contact time with the germs that is needed will be much shorter," added specialist Roselly Robles from Digemid.
Similarly, alcohol should have a minimum effect of 30 seconds on the skin, before allowing it to evaporate and dry on contact with air. Thus, it is reminded that alcohol gels would have the same degree of effectiveness and practicality; it would prevent the dehydration of the skin that they do cause in their original form.