Do urea/ammonium lactate combinations achieve better skin protection and hydration than either component alone?

Skin Pharmacol Appl Skin Physiol. 2002 Jan-Feb;15(1):35-43. doi: 10.1159/000049387.


Twenty subjects with healthy skin were treated with the following formulations for two weeks: drug-free W/O vehicle, 5% ammonium lactate (CAS 52003-58-4) in W/O vehicle, 5% urea (CAS 57-13-6) in W/O vehicle, 3% ammonium lactate + 3% urea in W/O vehicle, 5% ammonium lactate + 5% urea in W/O vehicle. These formulations were applied in randomized order to 6 test areas on the forearms; one area was left untreated. Repetitive washings were additionally performed in the second treatment week. TEWL, stratum corneum water content (corneometry-determined electrical capacitance), and cutaneous blood flow (laser Doppler) were measured at baseline, day 7, and day 14. 5% urea and both ammonium lactate/urea combinations produced significant stratum corneum hydration and improved stratum corneum barrier function; there were no significant differences between these three treatments.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Chemistry, Pharmaceutical
  • Double-Blind Method
  • Drug Combinations
  • Female
  • Humans
  • Lactic Acid / pharmacology*
  • Lactic Acid / therapeutic use
  • Male
  • Middle Aged
  • Quaternary Ammonium Compounds / pharmacology*
  • Quaternary Ammonium Compounds / therapeutic use
  • Skin / blood supply
  • Skin / drug effects*
  • Statistics, Nonparametric
  • Urea / pharmacology*
  • Urea / therapeutic use


  • Drug Combinations
  • Quaternary Ammonium Compounds
  • Lactic Acid
  • Urea