Introduction:

Human aging has been a mystery from the dawn of civilization because of its biological
complexity -genetic composition, inheritance, epigenetics—along with a constantly changing
living environment. Age is different from aging. Age can be identified as a unit of time, such
as years (e.g., chronological age). Aging is multifaceted. For example, lifespan/lifecycle is
viewed as the duration between the biological conception (gestation) of an individual to the
termination of life or death. However, individual genetic inheritance, generational changes,
and living environment in different age cohorts (and their bio-psycho-social characteristics)
complicate the understanding of aging. Nevertheless, the aging process demonstrates a constant
change in molecular composition in human cells with or without external environmental
stimuli.

There is a significant amount of research identifying several hallmarks of the aging process.
There are twelve hallmarks identified in relation to aging. All of them are specific changes at
the molecular level. Genomic instability, telomere attrition, epigenetic alterations, loss of
proteostasis, disabled macro autophagy, deregulated nutrient-sensing, mitochondrial
dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication,
chronic inflammation, and dysbiosis are the twelve hallmarks of aging1,2