A retrospective, double-center study evaluated the effects of a solution of low molecular weight hyaluronic acid (LMWHA) and highly concentrated oxygen (HCO) via the Caress Flow© device compared with hyaluronic acid (HA) alone on mild to moderate stress and mixed urinary incontinence in postmenopausal women with genitourinary menopausal syndrome (GSM). The study ran from October 2021 to September 2023, and patients were divided into two groups. The primary outcome was the patient's overall impression (PGI-I), the secondary outcomes were the ICIQ-SF and IQoL questionnaire. In the LMWHA and HCO combination group, 28 women (80%) reported symptom improvement (PGI-I ≤3), versus 7 women (21%) in the HA group. According to the ICIQ-SF, there was a statistically significant difference after treatment (median 7 [5–11] vs. 10 [8–11]; p = 0.03). The IQoL questionnaire showed a pre-treatment score of 71 [IQR 55–81] vs. 89 [IQR 67–94]; p < 0.01 and after treatment 78 [IQR 65–86] vs. 88. The combination of LMWHA and HCO improved incontinence in women with GSM more than HA alone, the results need to be confirmed in further controlled studies with a larger population.