Stages of the life of a Turkmen
0-12: childhood
13-25: adolescence
25-37: youth
37-49: maturity
49-61: prophetic
61-73: inspirational
73-85: wisdom
85-97: old age
97-109: Oguzkhan
The decree - published in a national newspaper - divides life into 12-year cycles.
This means that childhood for Turkmens will now last until the age of 12, youth to 37 and maturity to 49.
Later periods are also defined as the prophetic, inspiration and wisdom years.
Those lucky enough to live beyond 97 enter a period named Oguzkhan after the believed founder of the Turkmen nation.
However the average Turkmen citizen is unlikely to reach these twilight years, as men in the country on average live only until the age of 60 and women until the age of 65.
According to his own decree the 62-year-old Turkmen leader is in his inspirational period.
Eccentric commands
It is the latest unusual command by the eccentric leader of the former Soviet state, who last week proposed all 12 months of the year to be officially renamed in commemoration of the country's heroes and most potent national symbols.
The Turkmen leader proposes renaming January Turkmenbashi after his official name, which means Head of all the Turkmen.
Other months will be renamed to honour famous Turkmen poets and writers.
Mr Niyazov already has several schools, cities, airports and even a meteorite named after him.
Power extended
Turkmenistan's People's Council last week also called for Mr Niyazov to remain in power until his death, rejecting his proposal to step down and hold elections in 2010.
He was made president for life in 1999.
Mr Niyazov has ruled the country since he was appointed Communist Party chief in 1985 when it was still part of the Soviet Union.
He quickly developed a cult of personality surrounding himself, suppressing legitimate political opposition.
He has spent vast sums of money on lavish palaces and statues of himself, despite the country's increasing poverty.
Much of the cash for such grandiose projects is thought to stem from deals involving Turkmenistan's rich oil and gas reserves.