Table 3. Safety Results of the Included Studies .

Reference	Results
Salama and El-Sawy20	# CK activity increased insignificantly after 5-minute LED treatment. # Both SMI and SHCC remained stable after the treatment for 10 min.
Espey et al21	# No significant changes in the DFI were detected after therapy. # The pattern of CD46 expression confirmed the maintenance of acrosomal integrity after therapy.
Salman Yazdi et al22	# The results of SCD and HOS tests in the 10 J/cm2 group were not significantly different compared to the control group.
Safian et al23	# Both the Red and Red + NIR lasers at 0.6, 1.2 and 2.4 J/cm2 significantly decreased viability and increased DFI. However, this difference was not significant between NIR and control groups.
Allameh et al15	In this study, the safety of PBM in motility was not assessed and only motility tests were done.
Safian et al24	# DFI and LPL were significantly reduced in group 2 compared to group 1. # Early apoptosis and necrotic cells decreased significantly in group 2 compared to either group. # The expression levels of PRM1, PRM2, and ADD1 were not significantly different among the study groups. # PBM therapy prior to cryopreservation has a significant protective role against cryo-damage.
Frangez et al25	In this study, the safety of PBM in motility was not assessed and only motility tests were done.
Safian et al26	# No significant differences were observed in the morphological features. # PBM treatment before cryopreservation significantly increased the concentration of viable spermatozoa. # PBM before cryopreservation significantly increased the number of high MMP sperms and decreased the number of low MMP sperms post-thawing. # The PBM-preconditioning significantly decreased the intracellular ROS level and LPL.
Zupin et al27	# An increase in the Na + content was detected after PBM, suggesting that this change could be vital in the enhancement of sperm movement.
Gabel et al28	# SCSA assay revealed no increase in DFI from the very high doses of both laser and LED therapy.
Saeed et al29	In this study, the safety of PBM in motility was not assessed and only motility tests were done.
Firestone et al30	# DFI was not significantly different.
Shahar et al31	# ROS was produced after 1–3 min of light irradiation, while there was a significant reduction in ROS in the presence of SOD or azide. # Mitochondrial respiration is the main source of ROS produced by light therapy in sperms. # HAM in DCF loaded cells was enhanced by light. # Azide caused complete inhibition of the light effect on HAM. # Light therapy did not affect DFI. # Intracellular Ca2 + concentration increased significantly after PBM.
Fekrazad et al32	In this study, the safety of PBM in motility was not assessed and only motility tests were done.
Highland et al33	# The sperm viability significantly decreased in both groups after exposure to NIR which was higher in group 2 compared to group 1. # A significant decrease in the number of swollen spermatozoa was observed after NIR exposure in both groups as compared to pre-treated samples. # Percent of apoptotic cells increased more significantly after NIR exposure in both groups as compared to pre-treated groups. This increase was significantly higher in group 2 compared to group 1 post-treatment. # Toroid disruption increased insignificantly after NIR exposure in group 1, but group 2 showed a highly significant increase. # The number of sperms with normal chromatin dispersion decreased significantly in groups 1 and 2 after NIR exposure as compared to the pre-treated samples. # SOD activity diminished significantly after NIR exposure in both groups. # LPL increased significantly after NIR exposure in groups 1 and 2.

Abbreviations: SMI, sperm membrane integrity; HOS, hypo osmotic swelling test; SHCC, sperm head chromatin condensation; ANBS, aniline blue staining; DFI, DNA Fragmentation Index; LPL, lipid peroxidation level; PRM, gene expression levels of protamine; ADD1, adducin 1 alpha; MMP, mitochondrial membrane potential; ROS, reactive oxygen species; SCSA, sperm chromatin structure assay; SOD, super oxide dismutase.