Low-back pain has a high impact on the world population, and solutions are in demand. The behavior of specific physiological processes has been modified using magnetic fields, whether for pain relief, bone consolidation, or improvement of vascularization. The use of tape with magnetic properties could help in these cases. A double-blind randomized clinical trial was designed to use Magnetic Tape® versus placebo Kinesio tape. Blood flow variables were evaluated using pulsed power Doppler ultrasound. Resistance index, pulsatility index, systolic velocity, and diastolic velocity were measured. The pressure pain threshold was measured using algometry in 22 subjects. The results reveal significant differences between the groups for the pulsation index variable (8.06 [5.16, 20.16] in Magnetic Tape® versus 5.50 [4.56, 6.64] in Kinesio tape) and lower (0.98 [0.92, 1.02] for Magnetic Tape® versus 0.99 [0.95, 1.01] for Kinesio tape) in the resistance index variable. The pressure pain threshold variable presented significant differences at multiple levels. The application of Magnetic Tape® causes immediate effects on blood flow and pain and could be a technique of choice for pain modulation. Further studies would be necessary.