Will menstrual cup loosen my vagina?

Menstrual cup won't loose the vagina. When you have the cup in your vagina, your vaginal and pelvic floor muscles keep it in. So you actually kinda work out when you wear the cup.

If the cup won't stay in, it is usually because of the weak pelvic floor muscles. This is quite common, for example, after multiple child births or when person ages. Vaginal tissue also lose its elasticity when you age.

Kegel exercises strengthen the pelvic muscles and prevent future problems like urinary leakage. These muscles also have a lot to do with sexual pleasure so a big bonus there to do some training!