Where germs live on your hands

Not every part of your hand is equally germy. One spot carries far more bacteria than the rest.

  • First published May 18, 2008
  • Rewritten Sept 27, 2026

Bacteria per square centimeter

  • Under the fingernails61,368
  • Palm847
  • Back of the hand250
  • Between the fingers223
  • Top of the fingernails89

Colony-forming units (CFU) per cm², log scale. Source: McGinley, Larson & Leyden, J Clin Microbiol 1988.

What it means

The area under the nails is warm, protected and hard to reach, so bacteria build up there. A quick rinse or a sloppy rub misses it entirely. That’s why every handwashing method, including CDC’s and WHO’s, calls out the fingertips and nails.

What to do

  • Keep natural nails short. CDC’s guidance for healthcare workers is that they shouldn’t extend past the fingertip.
  • Scrub your fingertips and nails into the opposite palm every time you wash or use sanitizer.
  • If you work with high-risk patients, skip artificial nails. Germs survive under them even after hand rub.
Sources
  1. McGinley KJ, Larson EL, Leyden JJ. Composition and density of microflora in the subungual space of the hand. J Clin Microbiol. 1988;26(5):950-953.
  2. CDC. Clinical Safety: Hand Hygiene for Healthcare Workers.
  3. WHO. Guidelines on Hand Hygiene in Health Care. 2009.

Keep going