What’s The Hair Growth Cycle?

What’s The Hair Growth Cycle?

Hair growth is not as simple as you might assume - the hair growth process occurs in a cycle, with four different stages and, much like your fitness regimen, goes through phases of growth, transition, rest, and shedding.

Understanding the hair growth cycle will help you come to terms with why hair thins and falls out. In this post we explain each of the stages of the hair growth cycle, what causes hair loss and how to regrow your hair. 

You have approximately one hundred thousand hair follicles on your scalp and over the course of your life, you will not generate any new follicles. Each follicle has its own immune system and growth cycle. This means that at any given time, every hair will be at a different stage in the cycle. The length of time that is spent in each phase also differs from person to person.

Hair Growth Phases

The hair growth cycle is broken down into 4 stages – the anagen, catagen, telogen, and exogen phase. These stages have the following characteristics: 

Anagen Phase

  • This is the growth phase that lasts on average 2-7 years
  • The cells in the root of the hair are dividing rapidly
  • A new hair is formed, pushing out hair that has stopped growing or is no longer in this growth phase
  • This phase determines the length of hair and hairs grows approximately 1cm every 28 days

Catagen Phase

  • transitional phase that lasts about 10 days
  • The hair follicle shrinks, and the papilla detaches. This means that the hair no longer has its nourishing blood supply
  • 3% of your hair is in this phase at all times

Telogen Phase

  • This is the resting phase that lasts approximately 3-months
  • The hair follicle is at rest and 10% of your hairs are always in this phase

Exogen Phase

  • This phase is commonly considered part of the telogen phase and is associated with shedding the old hairs and making way for new hairs to grow
  • Humans are the only mammal where shedding hair is random and not seasonal. It is normal to shed 25 to 100 telogen hairs per day

Just like any other important process in your body, the hair growth process can be interrupted and affected by external factors like stress, nutrition, and illness. It can also be affected by male pattern balding.


Stress and Diet

The fact that the telogen phase lasts approximately 3-months means that any change in your stress levels or diet can result in hair loss that doesn’t happen until months later (when your hair enters the exogen phase). This means that if you suddenly start feeling stressed or stop getting enough vitamins or minerals from your diet, it could take months before your hair starts to thin or fall out. It is vital that you eat a healthy diet and manage your stress levels to ensure your hair maintains a healthy growth cycle.

Male Pattern Balding

Male pattern balding affects the hair growth process by making the effects of the catagen phase more severe. One of the primary causes of this is dihydrotestosterone or DHT, which attacks the hair follicle and causes the miniaturisation of hair follicles. Not all hairs are sensitive to DHT, so this type of hair loss typically occurs on the scalp and follows a recognisable pattern that enables you to identify whether the hair loss you are experiencing is a result of the genetic condition. A common sign of male pattern balding is when you notice that you are shedding more than 100 (telogen) hairs per day.

Hair Regrowth

To regrow your hair, you need to identify the cause of your hair loss.

Preventing hair loss because of stress will require active stress management techniques. Here are a few suggestions to try each day that could help you find your inner-zen:

  • Breathing exercises
  • Physical exercise
  • Meditation
  • Connecting with family and friends
  • Spending time in nature

If your hair loss is related to malnutrition, it is important that you visit your doctor and get checked for any mineral or vitamin deficiencies. You should also ensure that you are consuming a balanced diet.  

The best way to regrow some of the hair you have lost as a result of male pattern balding, is by blocking DHT and managing the levels of Prostaglandin D2 on your scalp. Typically, it is only possible to regrow hairs from follicles that are still active and healthy - this is why it is so important to treat male pattern balding as early as possible.