Skin patch testing or spot testing is critical for any new substance being introduced to the skin, especially potentially damaging ones like AHA (glycolic acid) peels.
 

If you’ve never used a peel before, you have no way of knowing how your skin will react. Even if you’re quite used to chemical peels, you will still want to do a patch test to determine how your skin will respond to a new brand of peel.
 

To perform a patch test:

  1. first pick an appropriate place to test
    • if you plan to use the peel on your face, pick an inconspicuous spot on or near the face (i.e. under the ear on the jawline)
    • if you plan to use the peel on your hands, try a spot on your wrist
  2. cleanse the test area thoroughly and pat dry (you don’t want to irritate the skin by rubbing dry)
  3. use a q-tip to apply a small amount of the peel to the test area
  4. let sit for about 1 minute and then neutralize (use common sense here: if the peel starts burning as soon as you apply it, neutralize immediately)
  5. if you feel fine after 1 minute, feel free to leave it on a bit longer
  6. after you’ve left it on for the duration you’d like to test, neutralize and remove
  7. wait 24 hours to determine the peel’s effect on your skin
  8. look for any signs of adverse reaction, such as
    • bumps
    • rash
    • redness
    • itchyness
  9. if you see no adverse reactions, proceed with the full peel with caution