Doesn't it seem like hair stops growing after a certain point? There are women who have hair that reaches way down their backs , but for others, growing hair to that length feels impossible.

For some, it seems hair gives up at some point, or perhaps has reached its full-growth capacity. But scientifically-speaking, we're curious: Will hair stop growing once it reaches a pre-determined length? How much does age factor in?

In this week's edition of Beauty Myths , we enlisted Elizabeth Cunnane Phillips, a trichologist at the Philip Kingsley Clinic in New York City who has been studying hair and scalp health for over 22 years, to clarify whether hair does indeed stop growing past a particular length or age in life.

"We are genetically pre-programmed to grow our hair to a certain length," confirms Cunnane Phillips. "There are three recognized phases to the typical growth cycle: anagen (the growth phase), catagen (a short resting phase) and telogen (the shedding phase that can result in the hair releasing over a period of time). The anagen phase can range anywhere from two to six years; this is what will determine the maximal length we can achieve."

Can certain events "shock" hair and essentially affect length? "Lifestyle and general health factors can contribute to that picture," notes Cunnane Phillips. "Stressful periods can cause an increase in the amount of hair we lose. It is not uncommon that three months or so following a very difficult time we can see an increase in hair loss when hair is washed or styled."

What about as we get older, does growth slow down? "As we live and breathe we are growing hair, but older age can bring with it variables that are not optimal for hair growth," says Cunnane Phillips. "Thus it seems that it grows more slowly. But a quick look around at the people in our lives suggests that they still trimming and coloring, so perhaps the frequency has changed somewhat, but we are still growing hair!"

But is there a certain age when hair is at its healthiest? "There is no magic age for 'healthiest hair," says Cunnane Phillips. "We see young women, who many consider to be at their prime, with hair issues. There are so many variables that have the ability to reflect in our ability to grow hair that we really treat it on a case by case basis. Variables that have the ability to influence its presentation and growth can be present at any age."

Conclusion: Maximum hair length is determined by one's anagen phase (period of growth), which can range anywhere from two to six years.

For Beauty Myths , we've enlisted the help of pros to help debunk and demystify some of the most popular advice out there. Do you have a myth you'd like us to investigate? Let us know in the comment section, and check out previous questions in the gallery below.

Check out these tips for growing hair out , and don't miss our favorite long-haired celebrities .

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