A stuck thermostat is not usually the cause of coolant loss or coolant leaks but sometimes if the coolant thermostat stays stuck closed for too long and builds up enough pressure in the radiator hose then it could cause a leak between the hose and thermostat housing or between the gasket of the thermostat housing or a leak could happen somewhere else down the line of the radiator hose and thermostat.
If your coolant thermostat is indeed stuck closed and not opening back up properly then your engine will also overheat due to the coolant not being able to flow through the radiator and engine properly.
Coolant loss is more commonly caused by a bad leaking gasket somewhere such as the water pump, thermostat housing, crack in a heater hose, leaking water pump, bad freeze plug etc.
If your radiator hoses are 10 years old or older as well as your heater hoses you should get them replaced as preventative maintenance because you don't want those hoses to burst as they can cause your engine to overheat if the hoses burst and then damage your engine as well as leave you stranded.