Diabetes mellitus (DM) is currently an important cause of morbidity and mortality. Global estimates indicate that 382 million people live with diabetes (8.3%), and that number could reach 592 million in 2035. The diabetic foot ulcers (DFU) present as sore wounds with disintegration of the skin. The DFU affect 15% of diabetic patients. Several studies have been conducted aiming to find therapeutic strategies for the healing of DFU, among the reported therapeutic methods the Low-level Laser Therapy (LLLT) has been highlighted. The aim of this study is to investigate the effects of different doses of LLLT in the treatment of DFU. Methods: This study is characterized as a double-blind randomized clinical trial (RCT), consisting of four groups, the control group will have only dressing and placebo LLLT application and the other three groups will have dressing and real LLLT GaAs 904 nm application. Expected outcomes: to elucidate the effects of different doses of LLLT GaAs 904 nm on the treatment of DFU, beyond to identify the most effective dose.

All groups will perform the same procedures twice weekly. Volunteers will be comfortable with the affected foot exposed. The diabetic foot ulcers (DFU) will be cleaned using saline solution and gauze, then the ulcer temperature will be checked using the digital infrared thermometer. Diabetic wounds will be measured and photographed at baseline and every 10 visits until the study is completed, the images will be analyzed using the ImageJ program for follow-up throughout the intervention. The DFU will be ranked according to the Wagner Scale. Afterwards the volunteers will receive LLLT application and conventional treatment in the form of Helianthus Annuus oil dressing. Both therapist and participant will be instructed on precautions to be observed when using LLLT. Goggles will be provided prior to administration. The lower cylinder of the LASER probe will be placed perpendicular to the DFU, the floor and edges of the ulcer will be irradiated using punctual and scanning techniques, respectively. Once a week blood glucose levels will be obtained for patient screening. All data will be recorded until the end of the visits in a control form prepared.

Inclusion Criteria:

• Type 2 diabetes mellitus patients with diabetic foot ulcers;
• Patients aged 18 and over.

Exclusion Criteria:

• Type 2 diabetes mellitus patients with ulcers in parts of the body other than the feet;
• Patients with infected diabetic foot ulcers.

Masking will be double-blind, the volunteer and outcome assessor will not be aware of the individual allocation of participants in the intervention groups.