Researchers discovered women feel most confident and happy with their love life and body shape shortly before they reach 30.
It is also the period in their life when they enjoy the best sex – but the happiness is relatively short lived.
Because by the time they have turned 30 they start worrying about growing old and developing grey hair and wrinkles.
A spokesman for home hair colour brand Clairol Perfect 10, which carried out the study of 4,000 women, said: "Everything in life hits its peak at some point, and nearly reaching your thirties isn't so bad now.
"The age of 28 has been pinpointed as the time in a woman's life their hair looks the best, body shape is at its peak and confidence is at an all-time high.
The survey of 25-65 year olds recorded the age at which women were most content in 12 key areas of their life.
According to the results, women are happiest in their career at 29 and most content with their relationships one year later at 30, despite having the best sex at 28.
But all is not lost for the over 30s, as women feel most content with their financial situation at 33 and at ease with their home and family life at 32.
The research found two thirds of women feel they age more quickly than men. It also emerged that 56 per cent of women worry about losing their looks as they get older.
But drinking from the fountain of youth doesn't come cheap as the average woman will spend ￡600 every year on beauty products in a bid to stay looking young.
The research also found women spend over five days a year on their beauty routine – an average of 22 minutes every day.