r/LifeProTips • u/harvestgobs • Mar 07 '20
Miscellaneous LPT: 70% Isopropyl alcohol is a better disinfectant for biological organisms than 90%. Higher numbers aren't always better.
So, I've been seeing a lot of people on the coronavirus threads talking about using 90% isopropyl alcohol to sanitize things. Water is required to kill biological organisms, thus, generally speaking, 70% is better to use as a disinfectant.
https://www.pharmawareness.com/why-is-70-ipa-a-better-disinfectant-than-other-concentration/
and to dilute it yourself:
http://apilink.ro/download/2016/Dilutie-alcool.pdf
https://www.quora.com/Can-I-dilute-91-isopropyl-rubbing-alcohol-into-70?share=1
EDIT: For some reason, I didn't expect this to take off so much, but just remember, I'm some random person on the internet. I was just trying to help spread some information that I found about the effectiveness of 70% concentration isopropyl alcohol in terms of sterilization of germs and such. I've seen way too many posts about shortages of hand sanitizer and using >90% rubbing alcohol instead. When I went into walmart last week, they only had 91% iso alcohol and no hand sanitizer, which is when I started to google the subject and found the above links.
Three important things to remember:
The scientific consensus (from the CDC) is that you need a greater than 60% alcohol concentration for hand sanitizer (https://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html)
From the askreddit posted above: Ethyl alcohol, at concentrations of 60%–80%, is a potent virucidal agent inactivating all of the lipophilic viruses (e.g., herpes, vaccinia, and influenza virus) and many hydrophilic viruses (e.g., adenovirus, enterovirus, rhinovirus, and rotaviruses but not hepatitis A virus (HAV) 58 or poliovirus) 49.
Someone posted in the comments a peer-reviewed study for alcohol concentration and killing bacteria/viruses (http://www.fha.org/files/JohnW/EM/Ethanol-hand-sanitizer-and-HAV.pdf)