Hand sanitizer requires just three or four ingredients: alcohol, glycerol, hydrogen peroxide, and water. The World Health Organization published two formulations designed for local production, and they remain the gold standard for making effective sanitizer at home. The key requirement is that your final product contains at least 60% ethanol or 70% isopropyl alcohol, which is the threshold needed to reliably kill most pathogens.
The Two WHO Formulations
The WHO offers two recipes, depending on which type of alcohol you can find. Both produce a liquid sanitizer, not a gel.
Ethanol-based formula (final concentrations):
- Ethanol: 80% by volume
- Glycerol: 1.45%
- Hydrogen peroxide: 0.125%
- Distilled or boiled water: remainder
Isopropyl alcohol-based formula (final concentrations):
- Isopropyl alcohol: 75% by volume
- Glycerol: 1.45%
- Hydrogen peroxide: 0.125%
- Distilled or boiled water: remainder
For a small batch of roughly one liter, you would combine about 833 mL of 96% ethanol (or 751 mL of 99.8% isopropyl alcohol) with 14.5 mL of glycerol, 41.7 mL of 3% hydrogen peroxide, and enough distilled or boiled water to bring the total volume to 1,000 mL. Mix in a clean container, then let it sit for 72 hours before use to allow the hydrogen peroxide to neutralize any bacterial spores that may have been present in the container or ingredients.
What Each Ingredient Does
The alcohol is the active germ-killing agent. It works by disrupting the outer membranes of bacteria and viruses, causing the membranes to leak and the cell’s internal enzymes to shut down. It also breaks apart the protective envelopes on many viruses. This is why concentration matters so much: below 60% ethanol, the alcohol evaporates before it can do enough damage to the pathogen.
Glycerol serves as a moisturizer. Alcohol strips oils from your skin, and repeated use can cause dryness, cracking, and irritation. The glycerol counteracts this by holding moisture against the skin. The WHO chose it specifically because it’s safe, inexpensive, and widely available. You can substitute other skin-safe moisturizers, but glycerol is the simplest option.
Hydrogen peroxide is not there to kill germs on your hands. It’s included at a very low concentration (0.125%) to eliminate any bacterial spores that might be contaminating the bottle or raw ingredients during production. It plays no role in the sanitizer’s effectiveness once you apply it.
Getting the Alcohol Concentration Right
This is where most homemade batches fail. If you start with rubbing alcohol that’s only 70% isopropyl alcohol and then add glycerol and water, you’ll dilute it well below the effective threshold. You need to start with high-concentration alcohol, typically 96% ethanol or 99% isopropyl alcohol, so that after dilution the final product still lands at 75% to 80%.
Vodka and most drinking spirits won’t work. Standard vodka is 40% alcohol, far too low even before you add anything else. A few high-proof grain alcohols (like Everclear at 95%) can technically work, but they’re expensive and not available everywhere. Pharmaceutical-grade or lab-grade ethanol and isopropyl alcohol are the intended starting materials.
Ingredients You Must Avoid
Never use methanol (wood alcohol). The FDA has documented cases of blindness, seizures, and death from hand sanitizers contaminated with methanol, in both adults and children. Methanol is toxic when absorbed through the skin and potentially fatal when ingested. It is not an acceptable substitute for ethanol or isopropyl alcohol under any circumstances. If an alcohol product doesn’t clearly label its contents, don’t use it.
Also avoid adding essential oils, aloe vera gel, or other thickeners without carefully recalculating your alcohol percentage. Many popular DIY recipes floating around the internet call for large amounts of aloe vera gel, which dilutes the alcohol below the effective threshold. A pleasant-smelling product that doesn’t kill germs defeats the purpose.
Mixing and Storing Your Batch
Use a clean glass or plastic container with a tight-fitting lid. Measure your ingredients carefully, using a graduated cylinder or measuring cup with milliliter markings. Pour the alcohol in first, then add the hydrogen peroxide, then the glycerol (which is thick and sticky, so you may need to rinse the measuring vessel with a bit of your distilled water to get it all out). Top off with water, seal, and gently swirl.
Let the mixture rest for 72 hours before you start using it. This waiting period gives the hydrogen peroxide time to deal with any contaminants introduced during mixing. After that, transfer it to smaller squeeze bottles or pump bottles for everyday use.
Shelf life is more forgiving than you might expect. A study examining hospital hand sanitizers found that the active ingredients remained stable for over 900 days after opening, with no decrease in disinfecting ability regardless of storage temperature or humidity. Still, keep the cap on when you’re not using it. An open container lets alcohol evaporate, and once the concentration drops below the effective range, the sanitizer becomes useless.
How to Use It Properly
Apply enough sanitizer to thoroughly wet both hands. Rub it over all surfaces of your hands and between your fingers until your skin is completely dry, which takes about 20 seconds. Don’t wipe or rinse off the sanitizer before it dries on its own. The alcohol needs that full contact time to work.
Hand sanitizer is less effective than soap and water when your hands are visibly dirty or greasy, because the grime creates a barrier between the alcohol and the germs. It also doesn’t work well against certain pathogens like norovirus. For everyday situations where soap isn’t available, though, a properly made sanitizer with the right alcohol concentration is highly effective.