Photodamage is a growing concern in contemporary society because promotes early skin aging and different pathologies resulting from prolonged and repeated exposure to ultraviolet solar radiation, which is considered the main extrinsic factor of this process. Affected by radiation, the hands play an important role in the manifestation and visibility of aging, as they are very exposed body regions. The study proposal is developed by the potential mechanism of tissue repair, skin rejuvenation, anti-inflammatory and analgesic effects of photobiomodulation, complementing the benefits of chemical peel. The main objective of this randomized, controlled, double-blind clinical trial is to compare the photorejuvenating effects of 20% trichloroacetic acid (TCM) peel applied alone and the effects of the association of 20% TCM peel with 660nm light emitting diode (LED) photobiomodulation (PBM) in the treatment of the back of the hands. Participants will be divided into 2 groups and will receive different therapies according to the allocation group. Group A will be subjected to 04 chemical peel sessions of 20% TCM and PBM. Group B will also receive the 04 chemical peel sessions of 20% TCM with PBM simulation. The application sessions will be monthly and the consultations for fortnightly evaluations. Analysis of photoaging characteristics such as fine and coarse wrinkles, dyschromias and global assessment of the back of the hands will be carried out using periodic standardized photographs. A visual-analog pain scale and a 5-point Likert scale will also be applied regularly to assess participants' satisfaction.

Participants will be divided into two groups for the treatment of photoaging of hands:

(A) Group 20% TCM + PBM: Application of chemical peel of 20% trichloroacetic acid solution in association with photobiomodulation with red spectrum LED (660nm) on the back of the hands.

(B) Group 20% TCM + PBM placebo: Application of chemical peel of 20% trichloroacetic acid solution in association with simulated photobiomodulation on the back of the hands.

It is observed that all participants included in the study will receive treatment recommended for photoaging on the back of the hands. The chemical peel (20% TCM solution) will be performed monthly, totaling 04 sessions with an average time of 40 minutes (guidelines, photos, skin exfoliation) with intervals of 04 weeks between applications. Biweekly assessments (guidelines and photos) will be carried out with an average time of 20 minutes during the study period. In addition, a group will also be subjected to photobiomodulation with 660nm LED during the sessions for the analysis of the association of therapies and comparison with exfoliation monotherapy.

It is noteworthy that both hands will be treated and control will be maintained in another randomized and uniform group, with no possibility of ethical compromise of different therapies with asymmetric results in the participants. Another important benefit provided by the separation of the control group will be the impossibility of light to influence the non-irradiated tissue. This case would occur if the hand subjected to photobiomodulation plus exfoliation was in the same individual as the hand subjected to exfoliation monotherapy. This influence is defended by countless scientists who research on the systemic effects of phototherapy.

In addition, both groups will prepare the skin properly before the treatments in order to enhance the effects of the exfoliation, allow the uniform penetration of the chemical solution in the back of the hands, decrease the healing time after the procedure and significantly reduce the risks of major complications such as post-inflammatory hyperpigmentation. Throughout the period, the participants will also be instructed on the importance of photoprotection with the daily use of factor 30 sunscreen. If there is a patient with severe hypersensitivity or major complications, the intervention will be discontinued immediately and properly treated according to its severity.

It should be noted that regardless of the results obtained at the end of the research, even if photobiomodulation improves or accelerates the benefits of chemical peeling, participants will not be submitted to new treatment sessions, as both groups will already receive treatment recommended for photoaging of hands. Furthermore, the application of photobiomodulation without the association of previous skin exfoliation is unlikely to bring better results, because early application after tissue injury is the most important factor for this purpose.

Inclusion Criteria:

• Individuals without comorbidities or with controlled comorbidities (ASA I and ASA II physical status classification).
• Participants must also have skin phototype I, II or III according to the Fitzpatrick classification.

Exclusion Criteria:

• Smoking, alcoholic, oncological, malnourished, anemic, pregnant, immunosuppressed participants.
• Patients with blood dyscrasias, psychiatric illnesses, collagen diseases (even with proper control), photosensitivity, individuals undergoing chemotherapy or hormone therapy and with scar changes (keloids and hypertrophic scar).
• Also excluded from the study are individuals who performed previous aesthetic procedures on their hands and use of medications that influence skin color, such as amiodarone, tetracyclines, tricyclic antidepressants, phenothiazines and others.