by chelsea schuyler

Hydrogen Peroxide Kills Stuff

Feel the burn! Ever get a cut and feel the need to apply first aid like the good scout you are? You might have a choice between two uncomfortable options, both will feel like burning: Hydgrogen peroxide and isopropyl alcohol.

But in actuality, only one of these things is actually doing any damage. The other is an illusion of sorts….

Hydrogen peroxide is the truly evil one – it will burst your very cells open. (Though the wussy grocery store kind is diluted down to 3% so it doesn’t hurt. But get the 12% like for hair dying, and you will feel that sucker).

Now, hydrogen peroxide’s been used as a first aid ingredient for decades because it kills the bad stuff. Technically, it destroys the cell walls of bacteria, which makes them explode, a la Hindenburg.

It’s an oxidizing agent, meaning it steals electrons from nearby victims, damaging or collapsing them entirely. Kinda like how stealing away Jenga tiles leaves the tower tilting precariously or crashing altogether (and upsetting the children).

However, since apparently it bursts your own living tissue as well, best to just clean your wound with soap and water and let your immune system handle it.

In fact, the immune system is actually using hydrogen peroxide already – our bodies make it! (Those cheapskates at Safeway…)

Hydrogen Peroxide in Your Immune System

When you get cut, your body’s hydrogen peroxide comes to the wound and signals your white blood cells, which come an average of 17 minutes later as the major backup that saves the day.

While hydrogen peroxide can do some damage, white blood cells spew out a medley of destroyers, including more hydrogen peroxide, but lots of other stuff too. It’s basically a weapons upgrade from the default gun to the flamethrower in all the cool video games.

Take away a body’s hydrogen peroxide, and you don’t get the white blood cell upgrade (this discovery was a big deal – scientists figured it out by ‘nicking’ zebrafish tails and gathering round to see what happened).

Keeping Hydrogen Peroxide at Bay

Wait, how do we keep hydrogen peroxide in our bodies if it’s a walking cell-bomb? Well, first, it’s isolated into little packages in our cells called peroxisomes. There, an enzyme (catalase) keeps hydrogen peroxide immobilized by splitting it into water and oxygen (from 2H₂O₂ to 2H₂O and O₂).

Now, hydrogen peroxide breaks down into water and oxygen naturally – if you left a bottle of it open for a long time it would eventually turn in a bottle of water. But this enzyme speeds up that process, resulting in oxygen bubbles flying out everywhere.

It’s like sending in a samurai to lop heads off some enemy army instead of just waiting for them to starve to death. Cuz who has the time?

Cleaning Trick

Ever get a blood stain on your shirt? A great trick is to put hydrogen peroxide on it and watch the alka seltzery chemical reaction of fizzy goodness. Bonus: the stain will disappear!

Why does that work? Because blood has catalase in it, so it reacts to the hydrogen peroxide, and all those oxygen heads are separated from water bodies, making the little bubbles you see. A water stain is left instead, which evaporates.

Why We Go Gray:

Fun fact: as we age our catalase production factories wear down and less of it is made. This leaves excess hydrogen peroxide free to wreak havoc…at least in hair cells.

Melanin gives our hair its color, but without its samurai catalase protector, hydrogen peroxide moves in and breaks it down. This is partly why our hair turns gray as we age.

Alcohol – It Burns!! Except Not

Once again, if you cut yourself (stop doing that) and decide to clean the wound with rubbing alcohol, you will feel a burning. But rubbing alcohol isn’t like hydrogen peroxide – it’s not doing any actual damage.

It’s actually similar to what happens when you swallow hard liquor (ethanol – different chemical makeup, but similar enough). That burning in your throat isn’t an actual burn.

The alcohol is actually tricking your body into thinking there should be pain there.

VR1 Receptors Will Believe Anything

If you want to know what the weather’s like, but you’re stuck in a dark room somewhere, your friend might stick their hand out the window and report back about whether it’s hot, cold, misting, wind-chilled, or humid.

Well, your body (and throat) has a bunch of vanilloid receptor 1s (VR1), which are basically a bajillion little arms sticking out, reaching out to see what’s happenin, and reporting back to the brain.

If you touch something that’s over about 107 degrees, the VR1s tell the brain “HEY – things are really heatin up in here.” And the brain goes “That must be painful. I mean literally, I shall make that painful so you avoid it.”

Well, ethanol reduces a VR1’s temperature threshold to 93 degrees, so when you pour that isopropyl on that wound, your body gets confused and registers its own body heat (98.6) as burning.

It then runs off tattle-taling to the brain going “FIRE FIRE!” and your brain goes “AAAH!!” when in actuality, nothing is happening. Except that your uncle’s Scotch has just turned your throat into a scourge of screaming throat-hands.

Cool huh? Just like they say in WestWorld – “Pain is just a program.”

(P.S. – That doesn’t mean alcohol doesn’t damage your throat though. It doesn’t burn, but it does wash away mucous membranes (hence dryness) and heighten your risk of throat cancer. Wee!)

Images in the public domain EXCEPT:
flamethrower – photo by Daniel Herrera, CC by 2.0
catalase – photo by CNX OpenStax, CC by 4.0
isopropyl alcohol – photo by Craig Spurrier, CC by 2.5