A randomized, double-blind, placebo-controlled study of collagen tripeptide bioavailability and improvement of skin condition

INTERVENTION: Group 1:Oral collagen tripeptide powder;Group 2:Oral collagen tripeptide and elastin peptide mixed preparation;Group 3:placebo; CONDITION: Skin aging PRIMARY OUTCOME: Skin elasticity;Skin wrinkles;Skin pores;Skin tone; SECONDARY OUTCOME: Skin microbiota;Skin metabolites;Fecal microbiota;Fecal metabolites;Blood biochemistry;Urine metabolites; INCLUSION CRITERIA: Healthy women aged 30‐55 years; Dry skin on the forearms according to self‐assessment; Photo types I‐IV (Fitzpatrick scale); Good general health and mental condition; Consent to the trial process and sign the informed consent form; Attend in person at the study group appointment time and be willing and able to adhere to the study rules and flow charts.