There is no minimum amount required to set aside in your MediSave Account (MA). A portion of your working contributions will be allocated to your MA until your balance reaches the Basic Healthcare Sum (BHS). The BHS is the estimated savings you need in your MA to cover your basic subsidised healthcare needs in old age and is the maximum amount you can hold in your MA. Any amount above the BHS will be channelled to your other CPF accounts, depending on your age. You can find out how MediSave contributions above the BHS are channelled to other CPF accounts via this
link.