Hydrogen peroxide vs Isopropyl alcohol: what is the difference?

How they differ

Both sit in the same first-aid cabinet and they kill microbes by different mechanisms. Hydrogen peroxide is an oxidiser: it breaks down into water and oxygen, and the fizzing on a cut is that reaction being catalysed by an enzyme in your own tissue. Isopropyl alcohol denatures proteins and dissolves membranes instead, which is faster and does not depend on contact with tissue enzymes. Peroxide is the milder disinfectant of the two at the 3 percent strength sold for household use, and it also damages healthy cells in a wound, which is why its use on open cuts has fallen out of favour. Alcohol evaporates and leaves nothing behind; peroxide leaves water.

Side by side

Common questions

What is the difference between Hydrogen peroxide and Isopropyl alcohol?

Both sit in the same first-aid cabinet and they kill microbes by different mechanisms. Hydrogen peroxide is an oxidiser: it breaks down into water and oxygen, and the fizzing on a cut is that reaction being catalysed by an enzyme in your own tissue. Isopropyl alcohol denatures proteins and dissolves membranes instead, which is faster and does not depend on contact with tissue enzymes.

Is Hydrogen peroxide bigger than Isopropyl alcohol?

Isopropyl alcohol is the heavier molecule, 60.1 g/mol against 34.02 g/mol for Hydrogen peroxide. Hydrogen peroxide is H2O2 and Isopropyl alcohol is C3H8O.