This double-blind, randomized, sham-controlled clinical trial aims to evaluate the effects of vascular photobiomodulation on blood pressure and vascular function in hypertensive patients treated with losartan. A total of 80 patients using losartan (100 mg/day for at least two months) will be recruited and followed for 4 weeks. Participants will be randomly allocated to either an active photobiomodulation group or a sham control group.

This is a double-blind, parallel-group, randomized, sham-controlled clinical trial. A total of 80 hypertensive patients under stable treatment with losartan (100 mg/day for at least two months) will be recruited and randomly allocated (1:1) to one of the following groups:

• Photobiomodulation Group;
• Sham Control Group.

The intervention will last 4 weeks, with two sessions per week, totaling 8 sessions. Each session will last 30 minutes.

The photobiomodulation intervention will consist of laser irradiation applied over the radial artery using a red laser (wavelength: 660 nm; power: 100 mW; duration: 30 minutes per session; total energy: 180 J per session). The sham group will undergo an identical procedure; however, the laser emission will be blocked to ensure no therapeutic effect. Blinding will be maintained for all participants and outcome assessors, with only the technician responsible for device setup aware of group allocation.

Assessments will be conducted at the following time points:

• Before and after the first intervention session (acute effects);
• Before and after the final intervention session (chronic effects).

Outcome measures will include:

• Blood pressure: office blood pressure (systolic and diastolic) measured using validated automated devices, and residential blood pressure monitoring throughout the study period using standardized protocols.
• Vascular function: endothelial function assessed by brachial artery flow-mediated dilation using Doppler ultrasound, following established guidelines.

Additional measures:

- Heart rate at rest and during assessments.

This study is designed as a feasibility trial to explore the potential synergistic effects of vascular photobiomodulation combined with losartan therapy in hypertensive patients without major comorbidities.

Inclusion Criteria:

• Patient in use of losartan at a dose of 100 mg/day divided into two doses as the only antihypertensive medication, for a minimum of 2 months.
• Present systolic blood pressure is less than or equal to 140 mmHg and diastolic less than or equal to 90 mmHg.
• Not having used any other antihypertensive medication in the last 2 months.
• Age between 18 and 65 years
• If female, not pregnant
• No cutaneous/subcutaneous lesions on both arms.
• No musculoskeletal, rheumatic, cardiovascular, metabolic, neurological, oncological, immunological, hematological, psychiatric or cognitive diagnoses and that may be worsened by the intervention or prevent the correct application of FBM vascular.

Exclusion Criteria:

• Changes in medication status during the study

We plan to share the protocol and data after the completion of the study

The protocol will be submitted briefly The data will be shared after the publication of the main results of the study

It will be open