Estriol is primarily used in hormone replacement therapy (HRT) to alleviate symptoms of menopause, such as hot flashes, vaginal dryness, and urinary discomfort. It is often preferred for its milder estrogenic effects compared to other estrogens, reducing the risk of side effects. Additionally, estriol is utilized in topical creams and ointments to treat vaginal atrophy and improve the health of vaginal tissues. It is also being studied for its potential role in managing multiple sclerosis, particularly in reducing relapse rates and improving symptoms. In some cases, estriol is included in formulations for skin care products to enhance skin elasticity and hydration. Its use is carefully monitored due to its hormonal activity, ensuring it is administered safely and effectively.