What to know about the 4 stages of hair growth

Fifty percent of women are expected to experience some form of hair loss or thinning when they turn 50. While genetics is an important factor, other factors can disrupt or support the natural hair growth cycle, affecting how it looks and feels. Understanding how your hair works optimally can help you better understand what’s really going on when you shed a few too many strands—and then develop a routine that gets to the root of the problem, rather than just masking it.

Here, Dr. Mamina Turegano, a certified dermatologist based in Louisiana, helps break down each phase of the hair growth cycle and shares her proactive approach to achieving stellar strands.

The four stages of hair growth

1. The antigen (growth) phase

“The antigen phase is when the follicle is in the process of producing hair, and the stage where most of your hair currently exists,” says Dr. Turegano. About 90 percent are in this growth phase now. How long your hair stays in this early stage is especially telling of how long you can – or can’t – let it grow. People who can grow very long hair (on the lower back and beyond) “genetically has an extremely long antigen phase,” she notes. “For most it lasts about three to five years, but for those with hair that can grow, this phase can last up to seven years.”

Courtesy of Michiru

2. The catagen phase (regression)

After a new hair has sprouted and fully formed, the follicle moves into the catagen phase, a short period in the hair growth cycle that typically lasts about a week to 10 days. “It is at this stage that the follicle begins to shrink at the base and separate from the bottom,” explains Dr. Turegano. “It’s not ready to go down yet, but it’s getting ready for the next phase.”

3. The telogen phase (resting)

This is an inactive phase that lasts about three to five months per strand, during which time the hair no longer grows. As a result, “the hairs are almost completely loose and ready to fall out,” says Dr. Turegano. She notes that at any given time, you’ll usually have some hairs in this phase that are ready to part, and other hairs newly growing in the antigen phase.

4. The exogenous phase (shedding)

This final stage of the cycle is when strands start to clump your hairbrush or fall down your favorite sweater. It’s totally normal to lose between 50 and 100 a day.

What affects the hair growth cycle

Dr. Turegano says she often caters to clients with hair loss and hair loss issues. “Telogen effluvium is the most common form of hair loss — where there’s been a shock to your body, either from an illness or a major stressful event like childbirth, surgery or a death in the family,” she says. “Your body sends a signal to the hair follicles, which then convert many hairs from the antigen growth phase to the telogen resting phase.” The result: a growth phase prematurely cut off much of your hair.

But keep in mind that due to the length of the telogen phase, you may not notice excessive shedding or thinning until three to five months later. “When patients come in with sudden hair loss, I do a thorough history and ask, ‘Okay, what happened three to five months ago?’” she says. “We can usually date it back to a specific event.” And this disruption of the delicate balance can have a domino effect. “It can take many months to recalibrate and get back into your normal growth phase – and that will also depend on whether you are still being exposed to that stressor,” says Dr. Turegano.

Committing to healthy hair is like a marathon.

Another factor that can lead to hair thinning is nutritional deficiency; the two most common involve iron and vitamin D, says Dr. Turegano. Simply replenishing your intake of these nutrients with a supplement can make a big difference in your hair’s health, she adds; however, it is best to consult your physician first for a personalized strategy. To deftly diagnose deficiencies, she does a full blood test, “just to rule out any easy fruit that we might sort out by recommending supplements.”

Plus, “there are underlying conditions that can exacerbate hair loss,” she says. “This can include thyroid disease, as well as hormonal issues, like when you have an extreme drop in estrogen — whether it’s menopause or postpartum — because estrogen can also help with hair follicle stimulation.” In other words, when the hormone wears off so sharply, so can your hair.

The condition of your scalp is also important. “One condition I see frequently on the scalp is seborrheic dermatitis, the most common cause of dandruff, which also causes inflammation,” she adds. “People get itchy and flaky scalps, which can exacerbate hair loss.”


Courtesy of Michiru

How to create a hair care routine that optimizes growth

Okay, so let’s assume you’ve got your stress levels under control, as well as your hormones, you’re eating a balanced diet while supplementing with a multivitamin, and a sunny, vitamin D-drenched vacation is just around the corner. You could still be sabotaging your wires. That’s because the way you consistently treat your hair—harsh chemical processes like highlights and coloring, heat styling, and more—can make straight, shiny strands dull and damaged way too soon.

Scalp health is essential for hair health.

Dr. Turegano helps her clients carefully curate a hair care routine specifically geared towards strengthening strands and supporting the scalp. She emphasizes the importance of treating your hair as gently as you treat your skin – minimizing chemical treatments and frequency, carefully combing out tangles, avoiding tight buns and ponytails, and wrapping delicate damp strands in soft microfiber towels at instead of common ones. how to choose the right shampoo, conditioner, and other products to promote a healthy scalp. “It’s essential when it comes to hair health,” she says. For clients with weight loss issues, she specifically recommends Michiru Fullness Shampoo It is Fullness Conditionerplus the brand hair tonic. Michiru infuses traditional Japanese extracts like senburi extract and silk protein into scientifically advanced formulations that nourish the scalp and help you achieve beautifully growing hair.

Fullness Shampoo
Fullness Conditioner
Michiru Fullness Conditioner
hair tonic

“Senburi extract, an herb native to Japan, has been shown to promote hair growth by helping to improve blood circulation in the scalp,” explains Dr. Turegano. “Silk protein can increase moisture retention in the hair shaft as well as improve elasticity and shine.” And the Scalp Tonic, which is applied directly to a clean scalp while hair is still damp, contains the antioxidant niacinamide, which “helps build, nourish and repair the skin barrier,” she adds. “We are learning more and more about the importance of the microbiome in our skin – we have billions, if not trillions, of bacteria living in this cohesive ecosystem on our skin and scalp. If our skin barrier is healthy, everything on the skin, including our hair follicles, can be healthier too.”

But remember, the hairs you see in the mirror every day are at different points in the growth cycle, so results won’t happen overnight. “The commitment to healthy hair is like a marathon,” says Dr. Turegano. As with skin care, committing to a scientifically proven routine is the real secret to transforming long-term scalp and hair health.

Nicole Catanese headshot

Nicole Catanese is a beauty and wellness editor.

What to know about the 4 stages of hair growth

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