8 Reasons Why Your Hair Won't Grow And What You Can Do About It

Have you ever sat down and wondered how you can get hair like Rapunzel? Maybe you're hoping your overgrown bangs will finally grow out, for instance. Whatever your reason, it can be frustrating when you feel your hair isn't growing fast enough. While it's possible to help your hair's growth, you have to determine what's causing your growth to slow down. Typically, hair grows only around half an inch per month, making it challenging to calculate daily hair growth. However, it's possible to deduce if you have hair growth issues by examining your lifestyle choices, overall health, and haircare routine.

Just like your height, your hair has a cycle of growth. This cycle is split into three parts: the anagen phase, the catagen phase, and the telogen phase. The anagen phase is the one where your hair is actively growing. This phase can last anywhere from two to eight years, except for pregnant women, who will remain in the anagen phase for their entire pregnancy.

The catagen phase lasts four to six weeks and serves as a transition period. During this phase, your hair isn't growing but isn't being hindered, either. The telogen phase lasts from two to three months and is the period in time in which your hair will consistently fall out. After a woman reaches menopause, this cycle slows down to happen every two years, and sees the hair becoming more thin and fragile (via Healthline). Let's discuss more in detail why your hair isn't growing — and what you can do about it.

As we mentioned, hair growth is divided into three phases. At the end period, the telogen phase, hair remains in a resting period before it eventually falls out and new growth begins. However, recent research has shown that stress can trigger our hair to enter into the telogen phase earlier than normal (via Nature). This is often due to the hormone cortisol that controls our body's response to perceived stress or threat. It plays a key role in preparing your body for flight or flight when under duress.

Unfortunately, this reaction also affects the way that hair grows — i.e., signaling to our hair follicle cells to go to rest early and stop dividing, thus preventing growth. While this example comes from a study on mice, there's evidence that stress likely has a similar effect on humans. For instance, childbirth is arguably one of the most stressful events for our body to go through.

It may be no surprise then that studies have highlighted postpartum hair loss as one of the "most common childbirth complications" (per the Iranian Journal of Dermatology). In fact, they show, as above, after childbirth, women experienced an extended telogen phase that lasted up to six months after birth, leading to subsequent hair loss and lack of growth. 

Aging is a natural process affecting all areas of the body, but interestingly, how it influences hair remains poorly understood. Although hair loss and graying are seemingly unavoidable aspects of growing older, the mechanism for these processes varies. For instance, according to research, one theory involves "the gradual loss" of melanocytes, which give our hair color (per Biology). However, the case of loss and inhibited growth is somewhat different.

One idea proposed by scientists is that aging causes mitochondrial dysfunction. Mitochondria are cellular organelles that help to power our cells, helping to break down and release the energy that our body needs to function. As we age, our mitochondria begin to lose their structure and functionality, which in turn means they can't do their jobs as well (via BioMed Research International).

Our hair follicle cells, like most cells in our body, derive the energy they need to grow in part from mitochondria. They help give our hair cells shape and density and stimulate the anagen phase, promoting hair growth. Unfortunately, though, since mitochondria are so involved in all these functions, their decline with age, conversely, means that the body is less able to coordinate and fulfill these tasks, leading to reduced hair growth and often loss.

Minerals and vitamins are an essential part of promoting hair growth. However, nutritional deficiencies are more common than you might think. A study by Oregon State University reported that 94.3% of the U.S. population have diets deficient in vitamin D and 88.5% in vitamin E, as well as other notable deficits in magnesium, calcium, and several other key vitamins. In these cases, many participants were meeting (if not exceeding) their daily caloric allowances, highlighting that it wasn't the quantity of food that was the problem — but the quality.

Specifically, we see that hair loss and the associated lack of growth may be a consequence of these diets. For instance, research shows that vitamin intake, such as Vitamin D, can "improve symptoms" of alopecia, a condition causing hair loss (per Dermatology and Therapy). And among other things, vitamins and micronutrients are key aspects of assisting our hair's growth phase, providing antioxidants that help with recovery during the telogen phase.

In fact, this is also where other aspects of our lifestyle come into play too. Antioxidants help to control oxidative stress, which is an imbalance of oxygen radicals that is often the starting point of many chronic and autoimmune diseases (per Oncotarget). And like nutrients, over time, regular physical exercise can help to minimize oxidative stress damage and, as a result, promote healthy hair growth.

There are several hormones that affect hair growth — starting with androgens, which comprise what is typically thought of as the "male hormones," such as testosterone and DHT (women also produce these hormones but in different amounts). Androgens control the thickness of hair, helping them to develop density over time. But not in all areas; excess androgen in the scalp inhibits hair growth, which is a predominant factor in hair loss (per the International Journal of Molecular Sciences).

Conversely, estrogen and progesterone are both hormones that support the anagen (growth) phase of hair follicles. However, as described by John Hopkins Medicine, during menopause, the level of these hormones in our bodies drops significantly. Estrogen, in particular, plays a crucial role in the skin's barrier functions, including the scalp, so its reduction leads to increase scalp dryness, as well as hair thinning and reduced growth.

There are also a few other hormones that may affect hair growth, such as prolactin, which mainly occurs during pregnancy. Usually, prolactin is formed in order to help breast milk production, but according to the Women's Center for Hair Loss, it also has a role in hair growth (or lack thereof). However, we likely shouldn't be too concerned with these changes as with menopause and pregnancy. Hormonal changes are normal, and you can consult your physician to help manage symptoms.

Most often, in the case of adult hair loss and breakage, the cause can be identified by the onset. By this, we mean it might occur due to hormonal changes, aging, diet, or other biological or environmental factors that change how our hair is structured at some point during our lives. But what determines how our hair is formed in the first place? Things like hair length, thickness, texture, and color are decided long before we are born, namely through the genes we receive from our parents.

For instance, research shows that aspects such as hair growth can be traced to how proteins are encoded by genes and, conversely, how mutations in these genes can cause excessive or poor growth (per PNAS). These gene mutations are often inherited, but even in their recessive form (i.e., even if you don't have the dominant gene trait) can affect hair growth in myriad ways.

At the most extreme end are often autosomal dominant conditions, described in the Journal of Dermatology and Therapy, meaning that they aren't determined by sex chromosomes, and only one parent needs to carry the gene for a person to inherit the trait. Common examples of this as it relates to hair are hypotrichosis (sparse hair growth), trichorrhexis nodosa (breakage-prone hair), and monilethrix (causing hair brittleness). You may not have the condition itself, but the effects of the mutated gene, even its recessive state, may affect your hair growth potential.

Thyroid hormones are another essential chemical messenger affecting many bodily processes, including growth and hair development. They help create cell proteins, initiating the hair growth cycle and maintaining the natural oils on our scalp. As a result, alterations to thyroid hormones, be it excess as in hyperthyroidism or lack as with hypothyroidism, has various consequences for hair health.

For instance, research from the Journal of Clinical Endocrinology and Metabolism shows excess thyroid hormones keep hair follicles in a prolonged anagen (growth) phase by inhibiting the chemical signals which tell the hair follicles to commence the next hair phase. At first glance, this might seem like a good thing. However, by repressing certain chemical signals, thyroid hormones also inadvertently suppress the mechanism used to eliminate unwanted cells.

This function, called keratinocyte apoptosis, is necessary to balance hair follicle production so that cells formed can also maintain their thickness and the correct structure. As a result, we see with hyperthyroidism, the hair may grow rapidly at first but be prone to brittleness, thinning, and dullness. It's important, therefore, if you are experiencing any of the symptoms of thyroid issues to address them with your physician to avoid hair loss.

One of the aspects of changes to hair growth that sometimes goes under the radar is the influences of medicational changes on the body. Some of the ones to be aware of, according to WebMD, are acne medications, antidepressants, birth control pills, medications that "suppress the immune system," cancer medications, steroids, mood stabilizers, high blood pressure medications, and more.

Often, such drugs (but not all) have a toxic effect on the body's hair matrix, which is part of the hair structure that contains actively reproducing hair cells. This site is the source of hair growth during the anagen phase of the hair growth cycle. The effect of some of the above medications conversely may push the hair cycle into an early resting state which can prevent growth or cause excess shedding.

It's important to stress, though, that you should never stop a medication that causes these symptoms without consulting a physician. In most cases, the effects of medication-induced hair loss and inhibition are usually not permanent. Moreover, the mechanisms of hair changes from medication vary widely, and stopping your treatment suddenly may worsen the effects. You should instead talk to your general practitioner for the best advice on how to manage side effects.

Alopecia is an umbrella term for a wide variety of issues referring to hair loss or baldness, which, as we've covered, can have various underlying causes. However, its subform, traction alopecia, is actually explicitly caused by traumatic styling techniques. This condition is a byproduct of traction or pulling from certain hair styling techniques, such as tightly pulled buns or ponytails, cornrows, hair extensions, or tightly braided hair (per the American Academy of Dermatology).

Over time, such hairstyles and others which exert continuous pressure on the hair follicles cause mechanical damage, setting off an inflammatory response in the scalp. The result of this inflammation is tiny bumps or pustules around the hair shaft that can inhibit hair growth and may contribute to scarring and eventual hair loss.

It's important to take note of the signs of this condition because when treated early, regrowth is far more likely. Firstly, the most common areas where you may begin to notice issues usually start at the fringe line, which is the front of the scalp along the hairline, and around the ears in the form of thinning. You might see specific patches of hair loss, overall thinning, pigmentation, or small bumps, depending on the style you use. If you notice any of these signs, your first call will likely be to a dermatologist who can assess the level of damage and recommend a haircare plan to prevent further hair loss.

If you've found that your hair isn't growing fast enough for you, there are a few foolproof ways to stimulate hair growth to help the process along. According to Good Housekeeping, the best course of action you can take is to trim any damaged parts consistently. After all, damaged hair can cause new strands of hair to fall out.

Apart from generally being a crucial aspect of a healthy lifestyle, upping your protein intake can help your hair grow faster and thicker. As well as protein, making sure you are consuming your daily nutrients and maintaining a healthy diet is crucial to helping your hair grow healthier. Since food is key for our bodily functions, it also plays a key role in the quantity and quality of our hair. 

Finally, to protect your hair from the outside, be sure to use the best products for your hair type to protect against heated tools. Make sure you are taking care of your hair with the same importance as you would care for any other part of your body. If these ways aren't working, you can also always turn to supplements that are specifically engineered to help hair growth. Sugarbear Hair Gummies, for instance, are taken daily and provide iron and vitamins C and B for better hair growth.