Does the use of Circadin® make the body less able to manufacture its own melatonin; i.e., does the natural melatonin system ‘switch off’ and, if so, does it switch back on again when Circadin® treatment is stopped?

Published literature has shown that administration of exogenous melatonin does not affect the endogenous production of melatonin^{18 19 14}. A long term study of Circadin^®, for up to 1 year, showed that melatonin rhythms are preserved in the patients even after 6 months of treatment²⁰.