Hand sanitizer, explained
How alcohol rub and antiseptic soap kill germs, why 60% alcohol matters, what sanitizer misses, and how to use it properly.
Two ways to kill germs on hands
Alcohol-based hand rub
The go-to in healthcare. It kills most bacteria, including MRSA, and many viruses within seconds, and it’s gentler on skin than constant washing. Look for 60% to 95% alcohol. Once it dries, it stops working.
Antiseptic soap
Hospital antiseptic washes usually contain chlorhexidine gluconate (CHG). Unlike alcohol, CHG binds to skin and keeps working for hours, which is why it’s used for surgical scrubs. Triclosan, once common, can no longer be sold in these washes without FDA approval.
What sanitizer can’t do
Alcohol rub is great, but it isn’t magic. Use soap and water instead for:
- Visibly dirty or greasy hands
- Norovirus (stomach bugs)
- C. difficile
- Cryptosporidium
- Chemicals like pesticides or lead
How to apply hand rub
Apply enough product to cover all surfaces of both hands. Rub for about 20 seconds, until your hands are dry.
Step 1. Cup your hand and apply product. Clasp your fingers of the other hand and be sure to apply product under your nails and cuticles.
Step 2. Rub your palms together. Be sure to apply product on your wrists.
Step 3. Rub the back of your hand while your fingers are interlaced.
Step 4. Rub your hands with your palms together with your fingers interlaced.
Step 5. Rub your fingers with your opposing palms to ensure you apply the top of your fingers.
Step 6. Rub your thumbs in a rotation with your palms.
Watch a medical director demonstrate it, or use our 20-second timer.
Quick questions
Does hand sanitizer keep working after it dries?
No. Alcohol kills germs quickly but has no lasting effect once it evaporates. Products that add chlorhexidine are the ones with lasting activity.
Is a higher alcohol percentage better?
Up to a point. CDC’s guideline says solutions with 60% to 95% alcohol work best, and that higher concentrations are actually less potent.
Why does sanitizer sting?
Alcohol stings on cuts and cracked skin. That’s a sign your skin needs some care; see our skin care tips.
Does hand sanitizer expire?
Yes, usually after two to three years, as the alcohol slowly evaporates. How to tell if yours is still good.
Can I make my own hand sanitizer?
CDC and FDA recommend against it, mainly because it’s hard to reach 60% alcohol at home. Why DIY recipes fall short.
Should I use sanitizer before putting on gloves?
In healthcare, yes. Clean your hands before putting gloves on and again after taking them off. Gloves are not a substitute for hand hygiene.
- CDC. Clinical Safety: Hand Hygiene for Healthcare Workers.
- CDC. About Hand Sanitizer.
- Boyce JM, Pittet D. Guideline for Hand Hygiene in Health-Care Settings. MMWR. 2002;51(RR-16).
- WHO. Guidelines on Hand Hygiene in Health Care. 2009.
- FDA. Health Care Antiseptics final rule. Federal Register, Dec 20, 2017.