Does the hair you leave in the shower, on your comb, or on your pillow make you feel concerned? If you’re worried that this is a sign of hair loss, don’t be — hair loss is a normal part of the hair growth cycle.

Of course, there’s such a thing as too much hair loss. Autoimmune problems, skin infections, stress, and other factors can lead to serious hair loss symptoms. Knowing what’s normal and what’s not is important when dealing with hair loss.

​How does hair grow?

Every hair on your head comes from a hair follicle. According to a study in the Dermatologic Clinics journal, each of these hair follicles goes through three different stages as part of the hair growth cycle. These are known as the anagen, catagen, and telogen phases.  

The first phase, the anagen phase, is also known as the growth phase. The anagen phase lasts for approximately three years. Hair growth rate during this phase is about 1 centimeter (0.4 of an inch) per month.

After the anagen phase, the hair follicle moves on to the catagen phase. In the catagen phase, the hair follicle shrinks over a period of about two weeks.

The third phase of hair growth lasts around three months. The telogen phase is known as a resting phase. It culminates with the fourth and final phase, known as the exogen phase, where the hair fiber is shed from the scalp. At the end of this phase, a new anagen phase should start.

Why do people lose hair?

Although all hair follicles go through the four hair growth phases, they don’t do so at the same time. If they did, we’d all go through a period every few years where our scalps would have no hair at all.

Obviously, this doesn’t happen. Instead, hair growth and hair loss stages are staggered. According to the Dermatologic Clinics study, at any given moment, most people have:

• 86 percent of their hair follicles in the anagen phase
• 1 percent of their hair follicles in the catagen phase
• 13 percent of their hair follicles in the telogen phase

Some hair loss is normal, as your scalp is constantly growing and shedding hair. But, when a phase lasts too long or the hair growth cycle is altered in some other way, future hair growth can be affected.

Altering the hair growth cycle can lead to hair loss. For instance, a study in the Journal of Clinical and Diagnostic Research says that a longer than average telogen phase could be a sign of telogen effluvium, which is a type of diffuse hair loss.

However, there are many other reasons you might lose hair. According to NYU Langone Health and a study in the Journal of Cosmetics, Dermatological Sciences, and Applications, hair loss is often influenced by hair shaft abnormalities and hereditary, hormonal, and microbial factors.

Understanding hair growth rate and hair loss

Hair growth and loss can be influenced by many different things. NYU Langone Health and the study in the Journal of Cosmetics, Dermatological Sciences and Applications say that diet can play a major role in your scalp’s health. Similarly, medications or dietary supplements you take can affect hair growth.

Certain health issues, like kidney or liver problems, extreme stress, and inadequate nutrition can also play a role in hair loss. Even the way you style your hair might contribute to hair loss.

You might not think that eating a lot of junk food can affect the health of your hair, but the Dermatology Practical and Conceptual journal says that it really comes down to the amount of nutrients you’re ingesting. For instance, if you’re not consuming enough of a certain nutrient, like zinc or certain B-complex vitamins, you might actually be contributing to your hair loss.

Unfortunately, sometimes hair loss is out of our control. According to a study in the Journal of Drugs in Dermatology, serious stress – like an illness or unexpectedly losing your job – can also cause hair loss.

Stress can occur for many reasons. Hair loss caused by virtually any problem – even an autoimmune issue or skin infection – can cause stress. This results in a cycle, where your hair loss is occurring due to the main issue, but worsened further by your stress.

Can you experience hair loss in stages?

Some hair loss is sudden, brief, and unexpected. That’s not true for all hair loss, though. In fact, a study in the Journal of Cutaneous and Aesthetic Surgery says that androgenetic alopecia (male pattern baldness), the most common form of hair loss, occurs in stages. 

The Norwood-Hamilton scale, which is one of the most common classification systems for hair loss, has defined seven different hair loss phases:

1. Hairline recession starts, but isn’t very obvious.
2. Hairline recession becomes more defined.
3. There is obvious hair loss at the temples and/or crown of the head.
4. There is little to no hair on a specific area of the crown of the head.
5. There is hair loss at both the front and crown of the head, but they are separated by a strip of hair.
6. The band of hair separating both sections of hair loss is lost, joining the two main areas of hair loss.
7. Hair loss is present on most of the head, except for the lower sides and back of the head.

It can be hard to be sure that you’re experiencing hair loss. The earlier you do identify the problem, though, the faster it can be treated.

Talk to your doctor if you’re experiencing hair loss but aren’t sure why. They can help you determine if your hair loss is a serious issue and why it’s occurring.

Hacking the hair growth cycle

If you’re having an issue with hair growth – or are losing more hair than you think you should, don’t worry. There are a variety of different ways to hack the hair growth cycle.

From surgeries to supplements, lots of different treatments can help support hair growth. Two popular treatments are finasteride, which is taken orally, and minoxidil, which is applied topically.

A different study in the Journal of Drugs and Dermatology particularly recommended minoxidil, as this treatment is effective for a variety of different types of hair loss. Minoxidil can be used for male pattern hair loss, autoimmune-related hair loss issues, and even certain congenital hair disorders.

Drugs like finasteride and minoxidil can be combined with other therapies, too. Generally, using multiple therapies is even more effective than using them one at a time.

Takeaway

If the hair growth cycle is affected, hair loss can occur in a variety of different ways. Other factors, like your diet or stress, can also contribute to hair loss.

If you’re not sure why hair loss is happening to you, talk to your doctor. They can help you determine the reason for your hair loss and recommend different treatment options that can help your hair grow back.