Study purpose: efficacy and safety of fractional Co2 laser versus fractional Nd:YAG in hand rejuvination determination. Study design: randomized, double blind, parallel, phase1 clinical trial. Target selection: patients referring to Shohadaye Tajrish Educational Hospital. Inclusion criteria: females aged between 45 and 75 years old; patients with mild to moderate hand sun damage. Exclusion criteria: females younger than 45 years old; cosmetic procedures affecting the treatment area (e.g., chemical peeling) within the last 6 months; oral administration of isotretinoin within the last 6 months; history of keloid formation. Target sample size: 36 patients. Study interventions: patients were randomly assigned to receive treatment on each hand, one with a fractional CO2 and one with a fractional Nd:YAG laser. Time of the intervention:3 treatment sessions with 1 month interval for each patient. Study outcome: the evaluation both before each treatment session and 3 months after the last one will be done with reviscometer and digital photography as well as assessment of side effects (eg., pain, stinging, pruritus, redness, bulla, bleeding, crust formation, hypopigmentation, hyperpigmentation, scar, atrophy) will be performed.