Skin aging is an irreversible, slow and progressive process. It is influenced mainly by age, but also by external factors such as ultraviolet radiation, smoking, alcohol, among others. It is increasingly common to look for procedures that slow this process by limiting or hiding its effects on the skin and its appearance. Intradermal platelet-rich plasma (PRP) injection is a new modality of treatment which has possible beneficial effects on skin rejuvenation. In addition, studies have shown photobiomodulation (PBM) benefits to the skin. The purpose of this paper is to investigate the effects of combined use of intradermal PRP injection on the face and photobiomodulation for facial rejuvenation. To this end, a randomized, double-blind, controlled clinical trial will be conducted with volunteer participants who wish to improve facial aesthetics, attended at the Nove de Julho University specialty medical outpatient clinic in the city of São Paulo. Participants will be divided into three groups: one group will undergo intradermal application of PRP in association with PBM; another group will undergo intradermal application of PRP and placebo light and a third group will receive intradermal application of 0.9% saline solution (placebo) associated with PBM. Only one application of PRP or saline solution will be performed at defined points on the face. PBM sessions will be held immediately after the first application of PRP or saline solution, 3 days after the first application and weekly for the next 3 weeks. The following variables will be studied for further analysis: face moldings analyzed by optical coherence tomography; skin viscoelasticity; histological study of the dermis; evolutionary comparison of photographic images by plastic surgeons (Wrinkle Assessment Scale) and participants' satisfaction level (FACE-Q). All data will be statistically evaluated according to their distribution.

Inclusion Criteria:

• Menopause (at least 12 months without menstruation);
• Healthy;
• Skin phototype from I to IV by Fitzpatrick classification.

Exclusion Criteria:

• History of photosensitivity;
• Use of corticosteroids, anticoagulants, or any drug known to increase photosensitivity, including systemic retinoids and topical retinoic acid use for the past 6 months;
• Carriers of any collagen-related diseases, malnutrition, anemia, immunosuppression, cancer diseases, smokers, predisposition to hypertrophic and keloid scarring, history of dermatological diseases, facial surgery, facial trauma, conditions that could affect skin condition and psychiatric diseases;
• Patients with blood dyscrasias and thrombocytopenia;
• Esthetic procedures on the face, such as botulinum toxin application in the last year, facial filling in the last 2 years, chemical peels, ablative laser and dermabrasion in the last year;
• Those who do not comply with post-treatment recommendations or fail to attend a treatment session;
• During the procedures those who present any type of complication (hematoma, allergies) will not be part of the statistical analysis, as these cases will not be in the expected pattern for these procedures. However, these data will be described and discussed, as well as possible adverse effects ,and participants will receive treatment to solve the condition.

A single researcher will perform the treatment and he/she will not perform any evaluation. Pre- and post-treatment evaluations will be made by four examiners (three plastic surgeons and one pathologist) who will not be aware of the group to which each patient will be allocated. Participants will not be aware of whether or not they have received the PRP, the application syringes will be camouflaged with opaque adhesive on the outside and they will not be aware whether or not they have received the PBM application as they will be using eye protection and the person who applies it will position the equipment at the irradiation sites on all participants and will only turn on the light in the specific experimental group. The characteristic sound of the device will be triggered by recording in the placebo groups for the PBM.