Fibromyalgia (FM) syndrome is defined by the American College of Rheumatology (ACR), as a chronic widespread pain and tenderness in at least eleven of eighteen specific tender points. Despite the increased understanding about FM, there is currently no cure for this syndrome and the treatment aims to provide symptomatic relief and improvement of physical capacities to perform daily tasks and quality of life. Evidence has suggest that photobiomodulation therapy (PBMT) can be used as monotherapy or as a supplementary treatment to other therapeutic procedures in patients with FM. However, the lack of consensus regarding therapeutic protocols hinders multicenter comparisons of the many clinical trials published. Further studies are needed to establish ideal parameters of PBMT to be used as a therapeutic tool in the management of fibromyalgia. Therefore, the aim of this project is to investigate the effectiveness of PBMT combined with static magnetic fields (sMF) in pain relief in patients with fibromyalgia.

To achieve the proposed objectives it will be performed a randomized, triple-blind, placebo-controlled trial, with voluntary patients with fibromyalgia. Ninety patients will be randomly allocated to two treatment groups: 1. Active PBMT (MR5™ ACTIV PRO LaserShower) or Placebo PBMT (MR5™ ACTIV PRO LaserShower). The patients will be treated by a blinded therapist.

The patients randomly allocated to the different groups will be subjected to treatment 3 times a week, total of 9 sessions (with approximately 48 hours between each session), a total of 3 weeks of treatment.

The clinical outcomes will be obtained at the stabilization phase, baseline, end of treatment and 30 days after the conclusion of treatment.

The data will be collected by a blinded assessor.

Statistical analyzis:

• The primary statistical method to analyze the primary endpoint will be Fisher's Exact Test to compare the proportion of success between the test (Active PBMT) and the control procedure (Placebo PBMT) groups, considering that randomization has been diligently conducted and important covariates between the two groups are well balanced. Statistical significance is set at p < 0.05.
• Unpaired T test will be applied to analyze pain intensity through EVA. Mean and individual subject changes in VAS ratings across and between all study evaluation time-points, within and between procedure groups considering that randomization has been diligently conducted and important covariates between the two groups are well balanced. Statistical significance is set at p<0.05.
• For patient satisfaction, measured through a Likert Scale, the data will be reduced to the nominal level by combining all agree and disagree responses into two categories of "accept" and "reject". Differences in satisfaction with Study Outcome Ratings between procedure groups at both evaluated time-points, and any change between. The chi-square, will be used after this transformation. Statistical significance is set at p<0.05.

The investigators will analyze: degree of pain rating (tender point count), pain intensity, patient satisfaction and adverse events

Inclusion Criteria:

• being female;
• age between 30 and 55 years;
• have an ovulatory cycle;
• height between 1.50m and 1.80m, body mass between 50 and 80 kg and BMI in the range of > or = to 18.5 kg/ m2;
• present a diagnosis of fibromyalgia and meet the current criteria of the American College of Rheumatology;
• had symptoms of fibromyalgia greater than 3 months;
• Widespread Pain Index (WPI) score > or = to 9, Visual Analogue Scale score > or = to 50 Fibromyalgia Impact Questionnaire score > or = to 50
• is not pregnant;
• not having diabetes mellitus and uncontrolled blood pressure;
• not having psychiatric illness or having malignant tumors;
• did not present dengue, Zika or Chikungunya in the last year;
• not to be hypersensitive to light;
• cognitive level enough to understand the procedures and follow the guidelines;
• consent to participate in the study and sign the consent form.

Exclusion Criteria:

• arthritis, chronic fatigue syndrome, lupus, auto-immune diseases;
• cognitive changes;
• people who perform some exercise;
• having a pacemaker;
• people under the age of 30 and more than 55 years;
• injuries in the last 6 months;
• not attend for more than two consecutive sessions;
• at any time and for any reason expressing an intention to leave the study.

A researcher will program the device (placebo or PMBT) and will be instructed not to inform the patients or other researchers as to the type of treatment (PMBT or placebo). Therefore, the researcher responsible for the treatment, the investigator and the outcome assessor will be blinded to the type of treatment being administered to the patients. The sounds and signals emitted from the device as well as the information displayed on the screen will be identical, regardless of the type of treatment (placebo or PBMT).