Many poets, writers and artists mention the fountain of youth in their works. They did it in the past, they do it now. A lot of expeditions have been organized in search of the fountain of youth. Some travellers have even claimed that they have finally found the place of the fountain. This symbol of eternal youth proves the fact that people have always been eager to find immortality.

The development of new technologies and sciences gives people hope that the key to eternal youth and life are around the corner. In order to understand how it can be possible to live long or eternally, one should first become aware of peculiarities of the human aging process. Many brilliant scientists were and are obsessed by finding clues and theories that can open the secret of human aging and how to prevent it.

While doing scientific research in the field of human aging, the term senescence has appeared. Senescence refers to the physiological human aging process, the process of showing that people get old. We are getting old due to a biochemical deregulation, a natural course of life. The human growth hormones is the only way to slow the process of human aging down.

The interesting fact is that senescence affects different species differently. Let us compare two mammal species that are about the same size: a bat and a rodent. We can find out that a bat generally lives longer, up to 30 years compared with a rodent, whose life span is only 2-3 years. Some animal species have a characteristic called the negligible senescence. Their life span is very long in comparison with other species and can reach 200 years. Such species as rockfish, turtles, and lobsters belong to this group.