Background and objective: Currently, there are no data on how the topical application of amino acids influences the complex moisture retaining system of the skin in vivo.
Patients/methods: An open study was performed to investigate the effects of topical application of arginine hydrochloride on epidermal stratum corneum urea content, transepidermal water loss, skin hydration, and clinical status of patients with atopic dermatitis and dry elderly skin.
Results: Treatment of patients with atopic dermatitis with 2.5% arginine hydrochloride ointment over 4 weeks showed a significant increase in urea in the stratum corneum as well as a continuous increase in skin moisture.
Conclusions: The urea deficit in the stratum corneum in atopic dermatitis and elderly skin was corrected not by applying the moisturizer urea itself but instead by using arginine - its precursor in the Krebs-Henseleit urea cycle. This topical treatment also improved the clinical symptoms of dry skin.