Table 1.

Summary of studies examining the efficacy of combined therapy versus monotherapy

Reference	Patient population	Experimental groups	Assessment	Results
Ferrara 2021 [16]	21 men with AGA	12 min of LLLT followed by topical minoxidil application (1 mL of 5% solution), to the affected scalp two times per day for 6 months. LLLT devices were modified such that the left half emitted light, and the right half did not	Efficacy assessed by blinded analyses of clinical photos and automated phototrichograms (TrichoScan) taken before treatment and after 3 and 6 months of treatment	In combined treatment group, the number of total hairs was significantly increased after 3 (p < 0.001) and 6 months (p = 0.001) An increase was observed on the minoxidil-only side, at both 3 (p < 0.001) and 6 months (p < 0.001) No statistically significant differences were detected between sides (p > 0.05)
Mahe 2021 [17]	135 volunteers with alopecia	Group A: 45 patients received full-head exposure of 0.1 J/cm2 once per day for 70 s and used minoxidil 2% twice daily for 5 straight days per week for 6 months Group B: 45 used minoxidil 5% twice daily for 5 consecutive days per week for 6 months Group C: 22 patients who received no treatment	Change in hair density measured by Tiff counting method Tiff counting method: phototrichogram photograph from pre-shaved area of the scalp of 1 cm2 New photographs are taken of the same precisely delineated area after 1.5, 3, 4, and 6 months of treatment	Similar increase in hair density in the combined treatment group and the 5% minoxidil treatment group compared to control At 6 months, the rate of increase in hair growth began to decrease in the 5% minoxidil group but was sustained in the combination group
Liu 2021 [14]	Ninety women (age between 18 and 60 years old) with FPHL	Group A: 30 patients received a 30-min laser helmet treatment with iHelmet device (650 nm) at home every other day for 6 months Group B: 30 patients used 5% minoxidil twice daily for 6 months Group C: 30 patients received a combination of both 5% minoxidil twice daily and iHelmet device (650 nm) 30 min every other day for 6 months	Hair density (n/cm2) and hair thickness evaluated by standardized phototrichograms recorded at baseline, 3 and 6 months The levels of scalp oil secretion assessed by TrichoScan digital image analysis conducted at baseline and 6 months Global macroscopic photographs taken at baseline and 6 months were assessed by 3 blinded experts	Hair microscopy and global photographs showed hair density and hair diameter of the three groups were significantly improved (p < 0.05) Sebum secretion significantly decreased in group A (LLLT) and group C (minoxidil and LLLT combination groups), but not in group B (minoxidil) Hair density: improvement of hair density in the combined group was higher than that in minoxidil Group (p = 0.036) and LLLT group (p = 0.012) Minoxidil group improved hair density to a higher degree than the LLLT group; difference was not statistically significant (0.409)
Esmat 2017 [13]	45 female patients with FPHL randomly divided into three equal groups	Group A: 15 patients applied topical minoxidil 5% twice daily Group B: 15 patients received LLLT using the iGrow helmet device for 25 min 3 days weekly Group C: 15 patients received a combination of both topical minoxidil 5% twice daily and LLLT for 25 min 3 days weekly for 4 months	Evaluation was done according to clinical, dermoscopic, and UBM parameters	The combination (group C) was best regarding Ludwig classification and patient satisfaction UBM and dermoscopic findings showed significant increase in the number of hair follicles at 4 months in all groups UBM showed such significant increase at 2 months in the combination group (C) only UBM at 4 months showed significant increase in the number of hair follicles detected in both groups B and C A nonsignificant increase in the hair diameter was also documented in the three groups
Faghihi 2018 [15]	50 patients with AGP The patients were randomly divided into a control and a treatment group	Group A received topical minoxidil 5% solution plus LLLT twice per day Group B Topical 5% minoxidil and a laser comb system that was turned off to act as a placebo	Changes in patients' hair density and diameter and overall regrowth as well as their satisfaction with the treatment were assessed at months 0, 3, 6, 9, and 12	Group A showed a significant increase in recovery percentage at 6, 9, and 12 months after the intervention (p < 0.001) compared to group B Mean hair count was higher in group A compared to group B at 9 and 12 months (p < 0.001) Group A showed an increase in hair diameter at 12 months compared to group B (p = 0.045) Mean increase in hair count was higher in group A compared to group B (78.3% versus. 51.3%; p < 0.001) Mean increase in hair diameter was higher in group A compared to group B (45.4% vs. 32.3%; p = 0.002)

UBM, ultrasound biomicroscopic.