Table 2. Efficacy Results of the Included Studies .

Reference	Intervention	Main Results of efficacy
Salama and El-Sawy20	Red LED (636.6 nm, 1.3 W, at 5 cm) at intervals of 2, 5, and 10 min (0.496, 1.241, 2.482 J/cm2 imposed energy).	# A significant increase in PR sperms and a significant decrease in IM sperms at every time point. # Motility peaked after 5 min, although this peak was not significantly higher than the one happening after 2 min. Then, the PR motility dropped significantly after arriving at the 10-min point. # Motility in washed samples was significantly higher than that in the non-washed samples. # A slight non-significant increase in sperm CK activity after 5 min of treatment was detected.
Espey et al21	Pulsed laser probe (655 nm, 50 mW/cm2, 200 sec. impulse duration) at intervals of 0, 30, 60, 90, and 120 min (4, 6, 10 J/cm2 imposed energy).	# Doses of 4 and 6 J/cm2 exhibited the strongest effect on motility and velocity. # The rate of PR raised toward the 32% threshold marker after treatment with 6 J/cm2. # In the time-independent comparison, the VSL increased in the AZ group after treatment with 4 J/cm2. # LIN & STR were negatively affected in NZ samples by 10 J/cm2. # LIN, STR & WOB increased in the AZ group by 6 J/cm2 in the overall group comparison.
Salman Yazdi et al22	GaAlAs laser (830 nm, 100 mW, 0.67 cm2 aperture size) at intervals of 0, 30, 45, and 60 min (0, 4, 6, and 10 J/cm2 imposed energy).	# Strongest significant increases in motility were observed in doses of 4 J/cm2 at 60 min, and 6 J/cm2 at 45 min. # The PR motility significantly increased at each time interval and each dose compared to controls. # The 10 J/cm2 group showed the least effect on motility.
Safian et al23	Group A: Red laser (630 nm); Group B: NIR laser (810 nm); Group C: Red + NIR laser. All at 18 cm at intervals of 15, 30, and 60 min. (0.6, 1.2, and 2.4 J/cm2 exposed energy).	# PR sperms in the groups exposed to the three energy densities of the Red + NIR lasers showed a significant increase only after 60 min in all energy densities. # PR sperms significantly increased in most of the groups exposed to the three energy densities of the NIR laser except the 1.2 J/cm2 after 30 min. # The best increase in motility resulted from the shortest radiation time (23 s) of the NIR laser at an energy density of 0.6 J/cm2. # This study confirmed the superiority of the NIR laser at 0.6 J/cm2 compared with the Red and Red + NIR protocols.
Allameh et al15	Light energy was transferred by laser fibers to several specific points performed by technicians of acupuncture using a Laser (810 nm, 300 mW, 18 J/min energy, at 90 degrees) on the skin at intervals of 5 to 10 seconds twice a week for consecutive 5 weeks. In the control group, sham laser acupuncture was performed. Three semen samples were taken from all patients; the first before the intervention, the second immediately after the intervention, and the third three months after the intervention.	# Sperm volume and morphology did not differ significantly in both control and intervention groups (all three samples). # Sperm motility and concentration were significantly higher only in the 3rd sample (3 months after the intervention).
Safian et al24	The control group underwent conventional sperm cryopreservation, group 2 underwent pre-freezing exposure (810 nm, diode laser, and 0.6 J/cm2), and group 3 underwent post-freezing and thawing PBM exposure.	# Group 2 exhibited the highest increased motility outcomes compared to groups 1 and 3.
Frangez et al25	Group 1: 850 nm, 2.16 mW/cm2; Group 2: a mix of 625, 660, 850 nm, 3.92 mW/cm2; Group 3: 470 nm, 5.06 mW/cm2; Group 4: a mix of 470, 625, 660 nm, 8.23 mW/cm2. All groups were exposed for 3 min., and their motility was evaluated 30 min. later.	# After treatment, the increase in the ratio of PR sperms was statistically significant in all investigated groups. # The improvement of sperm motility was the largest in group 3 semen samples, although not statistically different from the other treated groups. # This study indicates that LLLT using LED significantly improves sperm motility regardless of the wavelength.
Safian et al26	Samples received a single dose of NIR exposure from a laser diode (810 nm, 0.6 J/cm2, at 18 cm) before cryopreservation. Samples were analyzed 30, 60, and 90 min. after thawing.	# Results showed a significant motility increase in the NIR laser-preconditioning groups compared to the control.
Zupin et al27	Group L1: Class IV diode laser (800 nm, 0.1 W/cm2, 5 J/cm2); Group L2: Class IV diode laser (800 nm, 0.1 W/cm2, 15 J/cm2). Samples were analyzed at 0 and 60 min post-irradiation.	# The total motility increases or stays constant in all irradiated samples compared to that of the untreated ones. # Considering the progressive motility in a couple of cases, it can be seen that the L1 setting induces a decrease while L2 causes an increase, compared to that of the control samples.
Gabel et al28	The 104 LED cluster (56 x 660 nm, 10 mW and 48 x 850 nm, 30 mW, total power 2W at 5 cm with 39.5 mW/cm2) was projected for periods of 25, 50, and 75 seconds to the 1st frozen sample and 50, 100, 200, and 400 seconds to the fresh sample. The GaAlAs single divergent laser beam (200 mW, 810 nm, at 5 cm with 90 mW/cm2) was projected for periods of 10, 20, and 40 seconds to the 2nd frozen samples and 15, 20, and 30 seconds to the fresh sample.	# 30 min post-irradiation, a maximal effect on motility was achieved. # The 104 LED cluster caused just over a four-fold increase in motility with 75 s. exposure, whilst the laser produced an optimal effect of just below a four-fold increase at 20 s exposure. # The best effect on motility 30 min after exposure came from a treatment time of 50 s of LED while the longevity of the effect from higher doses diminished more rapidly. # The best overall longevity of sperm motility came from the shortest irradiation time (15 s). # The benefit from higher doses was shorter-lived.
Saeed et al29	Irradiated using a continuous He-Ne laser model (IFHN05) for 30 min.	# The results showed that 30-min laser irradiation increases the percentage of PR sperms significantly.
Firestone et al30	Irradiated with a laser system (905 nm, 50 mW/cm2, 1.5 J/cm2) for 30 seconds. Motility was assessed after 30 and 120 min.	# Results showed a statistically significant increase in motility in the treated samples 30 min after exposure. This difference was not observed 120 min after exposure. # Most significantly, those samples that were classified as both AZ + AO exhibited the greatest increase in motility (83.5%) as a result of the treatment.
Shahar et al31	Irradiated for 3 min. with 40 mW/cm2 visible light (400–800 nm) with maximum energy at 600 nm.	# Exposure caused a significant increase in PR sperms. However, no effect was seen on total motility. # This significant effect of light on PR sperms was seen within 10 min of incubation and it continued for at least 3 h. # A significant increase in VSL and LIN of the samples was observed 30 min after the treatment.
Fekrazad et al32	Red and Infrared lasers with 635 and 830 nm wavelengths were used.	# The mean total motility, PR motility, and VLC significantly increased in both Red and Infrared groups. The size of this effect was higher in the Infrared group, but the difference between the Red and Infrared groups was not significant.
Highland et al33	Exposed to a NIR source using a Philips Infrared bulb (750-1100 nm, 230 V, 50 Hz, 150 W) for a short duration of 15 min.	In this study, the efficacy of PBM in motility was not assessed and only safety tests were done.

Abbreviations: PR, progressive motile sperms; IM, immotile sperms; CK, creatine kinase; AZ, asthenozoospermic; NZ, normozoospermic; AO, asthenospermic and oligospermic; NIR, near infrared; VSL, straight-line velocity; LIN, linearity of the curvilinear path; STR, straightness of the average path; WOB, wobble parameter for oscillation; PBM, photobiomodulation.