What is the Hair Growth Cycle?

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Hair loss and hair thinning is one of the most dreaded parts of the aging process. Unfortunately for all of us, most researchers are still largely unsure as to how exactly we can stop hair loss. However, that doesn’t mean that there’s nothing you can do. Here is some relevant information to help you better understand the hair growth cycle and things you can do to slow down hair loss or speed up hair growth. 

What is the hair growth cycle?

We all approach hair care differently. How often we get it cut, how often we shampoo and condition our hair, the hair products we use, our diet, our lifestyle, and even our sleeping habits are all said to have an impact on our hair growth. However, researchers can’t quite pinpoint just how much impact these factors have. There is one thing that researchers agree on, and that is the hair cycle. Here are the three cycles:

  • The anagen phase - This phase is the period of growth. Hair actively grows from the roots for an average of 2-7 years before hair follicles become dormant. In this time, hair can grow anywhere between 18-30 inches (1)
  • The catagen phase - This period is short, only lasting 2-3 weeks on average. In this stage, hair stops growing and detaches itself from the blood supply
  • The telogen phase - This is the final stage of the cycle. The stage lasts around three months and includes the hair resting in the root while new hair begins to form in the resting hair follicles.

So how long exactly is the hair growth cycle? In total, this cycle can last anywhere from 2-8 years. It’s important to note that each hair follicle is completely independent and goes through the growth cycle at different times. 

How to Increase Hair Growth Cycle

As we mentioned earlier, there are several different factors that dictate your hair growth rate. The best way to try and increase your hair growth is to take steps during the anagen phase, where hair growth is at its highest. Here are some things that researchers and experts suggest doing to increase the speed of hair growth:

  • Increase your vitamin intake - If you’re experiencing nutritional deficiency you could be suffering from hair thinning and loss
  • Eat foods rich in protein and biotin - Biotin (Vitamin H) helps create protein in the body. Hair growth starts at the follicle, which is made of protein cells
  • Use coconut oil - Due to coconut’s oil molecular weight and structure, it directly sinks into the hair follicles instead of just sitting on top of the hair. This means that effects are not just surface level but rather it helps to also repair and stimulate the hair instead of being discarded after a wash (2)
  • Silk pillowcases - Cotton pillowcases can create friction which can lead to hair loss

Unfortunately, it’s still a mystery as to why some individuals have higher growth rates than others. Even still, researchers do believe that the tips above can help you increase your hair growth rate. 

Can Hair Grow Overnight?

Unfortunately, as of right now, there is no way to grow hair overnight. While hair follicles do grow overnight, they grow slowly. As we mentioned earlier, the anagen phase, where hair grows, can last anywhere from 2-7 years. Instead of focusing on overnight growth, something most researchers don’t believe in, you should focus on things to avoid. These things can negatively affect hair growth:

  • Genetics
  • Hormonal changes
  • Lack of nutrition
  • Medications 
  • Stress
  • Trauma that damages follicles
  • Diseases

It should be noted that if you are experiencing rapid and unexplained severe hair loss, you should consult with your doctor. There are certain illnesses and health conditions that can cause rapid hair loss. While we have established that it’s not likely you’re going to rapidly grow hair overnight, it should be noted that women who are pregnant may feel as though their hair is growing overnight. This is because, during pregnancy, the hormone estrogen actually causes a woman to have a higher ratio of hair follicles in the growing phase. After the baby is born, hair follicles return to the “resting” phase, making it appear as if they are shedding hair.

How fast does hair grow?

The American Academy of Dermatology claims that hair grows about half an inch per month on average. This adds up to a grand total of six inches per year for the hair on your head. When we lose hair it’s not because we lose the hair follicles. We are born with about five million hair follicles, 100,000 of them being on our heads. As we get older, some of those follicles stop producing hair. How fast your hair grows will depend on your:

  • Age
  • Specific hair type
  • Overall health
  • Other health conditions

Science has discovered a little bit about how hair growth is controlled at the cellular level in the body, but not enough to know how we can directly speed up hair growth

Can hair regrow after thinning?

Hair can regrow after thinning or hair loss but it does require time. It also depends on one major key factor - the underlying cause of your hair loss. Here is a quick breakdown of the structure of hair and the hair growth cycle depending on the reason for hair loss:

  • Pattern hair loss - Unfortunately, hair typically doesn’t grow back after pattern hair loss. This is because the follicle itself will shrivel up and is incapable of re-growing hair. Most men who have male pattern hair loss will eventually go bald
  • Alopecia - This is an autoimmune condition where the immune system mistakenly attacks hair follicles. It can be unpredictable and hair may start growing back at any time, but it may fall out again
  • Scalp psoriasis - This is also an autoimmune disease. It causes scaly red patches on the skin. Your hair will begin to grow back once you find an effective treatment for your psoriasis
  • Hormonal changes - Women can lose their hair during menopause or childbirth while men can lose hair due to hormonal changes as they age
  • Thyroid issues - Hair loss caused by thyroid disorders can usually be reversed after the thyroid disorder is successfully treated

If your hair loss is caused by a medical condition, you’ll need treatment to address the full condition, not just its symptoms, before the hair can recover.

Supplements Can Help Hair Growth

Taking care of your body with a proper diet, exercise routine, and supplement regimen can help you prevent hair loss. Supplements, such as a spermidine supplement, can help you live a longer life by inducing autophagy throughout your body. Autophagy is the body’s process of replacing older, potentially damaged cell parts, with newer healthier ones. 

This process becomes increasingly important as you get older and your cells become more and more worn down. Supplements can be beneficial because it can be difficult to get your recommended daily intake of spermidine through your diet alone. By taking a spermidine capsule with your dinner, you ensure that you always get your daily dose of spermidine. 




  • Don Moxley - Director of Applied Science

    Don Moxley is the Director of Applied Science at Longevity Labs. Moxley draws upon his career as an athlete, a sports scientist, and an instructor to lead and educate on the science of autophagy and longevity.