Objectives: To study lip hydration levels when applying a lipstick sunscreen for 3 months and to evaluate the influence of size of lips, age, sex, smoking and skin phototype. Study design: The study group was formed by 140 volunteer subjects, one group consisting of 70 patients applying a commercial lipstick sunscreen three times a day and the other group of 70 controls in which no product was applied. The age range was 20-86 years. The influence in lip hydration levels of age, sex, phototype, size of the lips and smoking habits was studied using a Corneometer 825® (Courage and Khazaka Electronic GmbH, Cologne, Germany). Results: An increase in lip hydration was found between the basal (53.49 ± 15.259) and final (59.34 ± 14.51) Corneometer 825® (Courage and Khazaka Electronic GmbH, Cologne, Germany) measurements over the three months of treatment, with statistically significant differences with respect to the control (p=0.002). However, no statistically significant differences in lip hydration were observed with regard to age, (p=0.48), gender (p=0.876), skin phototype (p=0.653), lip area (p=0.291) and smoking (p=0.178). Conclusions: Application of a lipstick sunscreen 3 times a day for 3 months increases lip hydration