## 4 Discussion
Other reports indicated that a healthy vaginal microbiota predominantly consists of _L. cripatus_, _L. jensenii_, and _L. iners_[41; 42]. In our study, increases in _Lactobacillus_ species after 2- or 4-week consumption of VGA-1 or VGA-2 (including the increase in _L. crispatus_ at week 2 for VGA-2 group), _L. jensenii_ and _L. gasseri_ at week 4 for VGA-1 group, and _L. iners_ at week 4 in the VGA-1 and VGA-2 groups, were observed (Table 4). We also observed that the abundance of _L. acidophilus_ in VGA-1 group was positively correlated with total _Lactobacillus_, _L. gasseri_, or _L. crispatus_ (Figure S6). Thus, the consumption of VGA-1 or VGA-2 increased the abundance of vaginal _Lactobacillus_ species to achieve beneficial effects to BV. A limitation of this study was that this was not a placebo controlled trial. The main reason for not including a placebo group was the medication rights of BV patients because they strongly suffer in vaginal itching and the strong fishy smell of vaginal secretion. In addition, probiotics interventions by oral consumption or vaginal implantation are widely considered to improve clinical symptoms of BV [43; 44]. [PERSON] et al. conducted a trial to investigate GR-1/RC-14 and tinidazole's efficacy combined with tinidazole single-agent treatment for 28 days. The Amsel test's positive rate was decreased to 12.5% in a combination of antibiotics and probiotics group, whereas 50% of subjects in the placebo group remained positive in the Amsel test [16]. [PERSON] et al. conducted a trial of probiotics vaginal tablet in BV subjects, for 28 days or 56 days, and the results indicated that 58.3% of subjects with a probiotics vaginal tablet implantation, displayed a decreased Nugent score less than 4, whereas the reduction in Nugent score in the placebo group did not show a significant difference. Furthermore, the self-recovery time of subjects in the placebo group was more than 56 days in this trial [45]. These trials clearly demonstrate that probiotics interventions are beneficial to BV patients, which could be distinguished from placebo effects. The trials of medical interventions in BV without a placebo group are not uncommon, such as the trial of _L. [PERSON]_ BMX 54 in BV subjects with concomitant HPV-infections [46] or vaginal lactoferrin administration in BV patients [47]. Based on these reasons, the goal of our trial was to compare the efficacy of two combinations of GNML _Lactobacillus_ strains and the results indicated that the improvement effect of VGA-1 worked faster than VGA-2, as there was a reduction in vaginal discharge odor/color, secretion, and itching after 2-week-consumption (Figure 4E). The decreased Nugent score was observed in 66.7% or 77.8% of subjects in the VGA-1 group at 2-week or 4-week-consumption, respectively (Table S9). The decreased Nugent score was only observed in 52.6% or 57.9% of subjects in the VGA-2 group at 2-week or 4-week, respectively (Table S9). Although we could not rule out the spontaneous recovery of subjects in VGA-1 or VGA-2 consumption group, the differences in the efficiency in the improvement of clinical symptoms between the VGA-1 and VGA-2 group might reduce the concern of placebo effects. In the future, it is necessary to design a placebo controlled trial involving more subjects for VGA-1 to clearly prove the improvement effect in BV.