Geroprotective properties of peptides are associated with their influence on systems maintaining homeostasis in the body and regulation of mechanisms underlying aging. Peptides normalize synthesis of tissue-specific proteins and regulate expression of genes responsible for proliferation and differentiation of cells. Thus, peptides maintain normal physiological functions and decelerate aging.

Exposure of male rats to permanent or natural illumination of North-Western Russia accelerated their death in comparison with animals exposed to standard (12 h) light. Permanent illumination promoted the development of spontaneous tumors in comparison with the standard photoregimen. Injection of epithalone (synthetic Ala-Glu-Asp-Gly peptide; subcutaneously 0.1 microgram/rat 5 times a week from the age of 4 months until natural death) virtually did not change the mean lifespan of male rats, but was associated with a significant (p<0.05) normalization of population aging rate and hence, time of mortality rate doubling in groups exposed to natural or constant illumination.

Epithalone injected to rats exposed to any photoregimen significantly inhibited the development of spontaneous tumors, primarily testicular leydigomas and leukemias.