Melatonin has a great ability to penetrate all cells of the body thanks to a relatively simple, lipophilic and small molecule. So it easily overcomes cell membrane and reaches the nucleus and mitochondria . Within the cell it appears to have an effect at the level of mitochondria . In experiments with mice with accelerated aging they have reported increased survival and longevity by 35 % and 17 % respectively.
The effects of melatonin in these mice were explored and found that the main target of melatonin occurs at the level of mitochondria whose senescence is the cause of many cellular deaths and associated diseases . Melatonin counteracts many of the manifestations of aging such as increasing free radicals level, nitric oxide and inflammatory substances such as cytokines .
 Improved mitochondrial function and increased life span after chronic melatonin treatment in senescent prone mice. Rodríguez MI1, Escames G, López LC, López A, García JA, Ortiz F, Sánchez V, Romeu M, Acuña-Castroviejo D.