Background: Genitourinary syndrome is a common, chronic condition associated with estrogen deficiency that negatively impacts vaginal health, sexual function, and quality of life in peri- and postmenopausal women. Non-hormonal vaginal moisturizers represent an important therapeutic option for women who cannot or do not wish to use estrogen therapy. Objective: The aim of this study was to evaluate the safety and efficacy of Provagin^®, a hyaluronic acid–based non-hormonal vaginal moisturizer, in postmenopausal women with mild to moderate vaginal dryness. Methods: This was a prospective, single-center, open-label, before-and-after clinical study with sexually active postmenopausal women. Participants applied 3 g of Provagin^® intravaginally every three days for 22 ± 2 days. Clinical assessments were conducted at baseline, 24 and 72 h after first application, and after 6 and 22 days of use. Outcomes included vaginal pH, vaginal microbiota, epithelial integrity, participant-reported symptoms (vaginal dryness, dyspareunia, and pruritus), and adverse events. Results: A total of 45 participants completed the study. Vaginal pH remained stable throughout the study period. No clinically relevant changes were observed in vaginal microbiota, except for a significant increase in Lactobacillus spp. counts. Epithelial integrity was preserved at all time points. Significant improvements in participant-reported symptoms were observed as early as 24 h after first use and continued through the study, with mean vaginal dryness scores decreasing by 69.3%. Conclusions: Provagin^® demonstrated a safety profile and was associated with improvements of genitourinary syndrome of menopause (GSM), without affecting vaginal pH, microbiota composition, or vaginal epithelial integrity. These findings support the use of Provagin^® as a safe, non-hormonal therapeutic option for postmenopausal women with GSM.