A structural molecular model of the hormone Melatonin. It is an antioxidant and a regulator of circadian rhythms, one can use it as a drug for jet-lag. Isolated on white. Shutterstock . vector - A structural molecular model of the hormone Melatonin. It is an antioxidant and a regulator of circadian rhythms, one can use it as a drug for jet-lag. Isolated on white. - ID: 171615884