While it is impossible to overdose on vitamin D from sunlight, it is impossible to overdose on it from supplements.
Adults, say the NHS, should have no more than 4,000IU (100 micrograms) per day.
Taking too much vitamin D over a long period can lead to serious problems, including damage to the heart, kidneys and bones.
This is because of the build up of too much calcium in the body, a condition known as hypercalcaemia.
