It was a randomised controlled clinical trial:
https://pubmed.ncbi.nlm.nih.gov/26793732/ "Comparison of the Hyaluronic Acid Vaginal Cream and Conjugated Estrogen Used in Treatment of Vaginal Atrophy of Menopause Women: A Randomized Controlled Clinical Trial"
"Results: The results of this study showed that the symptoms of vaginal atrophy compared with the baseline level were relieved significantly in both groups. Dryness, itching, maturation index, PH and composite score of the vaginal symptoms were relieved significantly in both groups (P<0.001). Dyspareunia in Premarin (P<0.05) and hyaluronic acid (P<0.001) decreased compared with pre-treatment. Urinary incontinence only showed improvement in the hyaluronic acid group (P<0.05). Improvement in urinary incontinence, dryness, maturation index (P<0.05) and composite score of vaginal symptoms (P<0.001) in the hyaluronic acid group was better than those in the Premarin group.
Conclusion: According to the results of the present study, hyaluronic acid and conjugated estrogen improved the symptoms of vaginal atrophy. But hyaluronic acid was more effective and this drug is suggested for those who do not want to or cannot take local hormone treatment."