What Makes Your Hair Grow?
If you’re looking up the question, “What makes your hair grow?” you probably want to know so that you can try to make your hair grow longer, faster, or fuller.
As you have probably found out the hard way, most methods that “promise” to help you grow your hair long are basically just snake oil in one form or another.
For that reason, maybe you are also seeking a deeper understanding of how and why hair grows. The more you understand about the science behind hair growth, the easier it will be for you to identify products and methods that can actually help you (and quit wasting money on those that can’t).
After I delve into the science, I will talk about some myths people have about what makes hair grow—things people suggest you try which will not actually promote hair growth. Then I will give you advice for maintenance and give you a few tips which can actually help your hair grow!
Why Do We Have Hair in the First Place?
This is a question that I have wondered about for most of my life, but for some reason it took me ages to actually look into it and try to figure out the answer. After all, you can go bald and it’s not like it has any impact on your health or survival (except maybe your social survival!). So if hair isn’t necessary, why did we evolve to have it at all?
The reality is, scientists are still not completely sure why hair, feathers, or scales evolved at all. New theories are proposed on an ongoing basis. One obvious reason why mammals may benefit from fur (and hair by extension) is as a means to stay warm. Consider how furry apes are. At one point, human beings had quite a bit body hair as well.
So why did that fur largely go away, except for the long hair on our heads? Scientists aren’t sure about that either, but there are several theories:
- We might at one point have been semi-aquatic (consider that there is webbing on our hands).
- When our ancestors ventured into the African savannah, they shed their fur to stay cool.
- Human beings shed fur to get rid of parasites like lice and ticks and fleas which were infesting it.
Scientists are also not sure why we have evolved so that we have lost most of our body hair (fur), but we still are able to grow long hair from our heads. What purpose would that long scalp hair serve? One idea is that perhaps it makes sense to have extra scalp insulation since we lose most of our heat through our heads. It is also possible that long hair provided necessary protection from the sun for the head, neck, and shoulders.
Whatever the case may be in terms of evolutionary advantage, sadly, you cannot make your hair grow faster just by spending more time out in the sun or the cold weather.
How Does Hair Grow?
So regardless of why hair grows, it helps to learn a bit more about how it grows.
Your hair has two main structures:
- The hair shaft, which is the part of your hair that you see
- The hair follicle, which is a structure underneath your scalp
What Goes On Inside the Hair Follicle?
The follicle is where hair is produced. You can think of it as a kind of miniature biological factory. It has the shape of a tunnel and extends down through the epidermis into the dermis (a deeper layer of skin). There are a number of structures inside the hair follicle which have different functions. For example, one structure is called the papilla. This structure is located at the very base of the follicle and contains a number of capillaries. When you eat the right diet for hair growth, the nutrients are delivered to the hair follicle through the papilla.
You have probably heard that “hair is dead.” For the most part this is true—and it should tip you off when it comes to identifying a lot of the snake oil “hair growth” solutions and superstitions which are based on the false premise that hair is alive at the ends.
For example, consider the assertion that trimming your hair on a regular basis makes it grow faster. Cutting the ends of your hair might have some impact on the rate of growth if the ends were alive, but they are not. How can cutting way dead cells possibly impact growth? It can’t.
That is why the belief that trimming hair regularly makes it grow is a myth.
Part of your hair is alive, but it is located inside the follicle in your scalp! It is called the bulb, and it surrounds the papilla—that little bundle of capillaries that delivers nourishment. Ever wonder why your body can produce hair so much faster than other forms of tissue? The bulbs inside the cell divide quite frequently—once every 23-72 hours or so!
What Goes On Inside the Hair Shaft?
Well, as previously mentioned, your hair shaft is dead. It is made up of keratin, which is a type of protein, but that protein is inert. Nonetheless, how you treat your hair can impact its structure. There are (usually) three layers to hair—the innermost is called the medulla. The layer that goes around that is called the cortex, and the outermost layer is the cuticle. If you have very thin hair, you may not have a medulla.
The structure of the cuticle looks a bit like siding with shingles if you were to zoom in on it through a microscope. Those shingles or scales overlap to protect the inner parts of the hair shaft. The pigment is contained in the cuticle, and the texture of the cuticle determines the texture and shine of your hair. If you mistreat your hair, the cuticle scales will not lie flat, and you will not get that nice shine. The structure of the hair will also be weakened and prone to breakage. The color may not be as vibrant either.
How Hair Grows
Hair grows at a rate of roughly half an inch per month. There is some very slight variation depending on various factors, but you are never going to see several inches of growth in a single month.
So if you see a product or technique that promises that, don’t spend your money on it! It is simply not going to happen.
While human hair growth is not cyclical the way it is for other species (some hairs on your scalp are always in each of the three phases I will talk about below), hair may grow faster during the summer than it does during the winter.
Here are the three phases of hair growth:
- Anagen Phase: Hair can be in this active growing phase for anywhere from two to six years. At this point the cells in the bulb are dividing every 23-72 hours as mentioned earlier. If there is a hair in the resting phase (more on that in a moment) above it, it will push it out. It will then emerge from the scalp as a new hair and continue to grow for two to six years. Ever wonder why your eyelashes and eyebrows never get long like the hair on the top of your head? It is because they have a very short Anagen phase! The vast majority of the hairs on your scalp are in the Anagen growing phase at any one time.
- Catagen Phase: This phase is a transitional one. Generally, about three percent of your hairs are in this phase at any one time. It is also a very brief phase, lasting around two to three weeks on average. During this phase the hair stops growing and forms what is known as “club” hair. This is simply hair which is no longer growing.
- Telogen Phase: This is the resting phase which I mentioned previously. It lasts signifncantly longer than the Catagen phase, but is still only several months long—usually around 100 days in total. This phase is briefer for eyebrow and eyelash hairs. Eight percent of your hairs are in the resting phase at any one time. The hair is effectively dead at this point. In fact, if you pull out a “club” hair in the resting phase, you will notice some white stuff at the root. Every day, you lose a lot of telogen hairs, sometimes as many as 100! And that is when your hair is healthy and not thinning or balding at all!
Why Does Hair Fall Out or Stop Growing?
Usually, this cycle occurs without any problems or disruptions. When it does, your hair grows as usual.
Sometimes, though, something happens which does disrupts the process. When that occurs, the growth cycle for hairs may be suspended. This is usually the result of an acute or chronic stressor. There may be a delay before your hair starts falling out, but once it does, you may lose it in handfuls.
Stress can make your hair fall out, but it’s important to know that when doctors talk about stress causing hair loss, they aren’t referring to a phone call from your mother-in-law or a bad traffic jam on the interstate. Usually they are referring to something like extreme weight loss, malnutrition, or a high fever or recent surgery.
Sometimes severe emotional trauma may lead to hair loss if it leads you to make poor lifestyle choices. If for example your spouse dies and you quit eating, you will probably lose a lot of weight, and, subsequently, a lot of hair. You can read more about the complex relationship between stress and hair loss here. Once the acute stressor is removed (or diminished), your hair will begin growing again as usual. It takes some time to replace the hair you’ve lost, but after a few months you should see significant improvement.
Another disruption which eventually happens to everyone is age. Aging has several different effects on hair:
- Graying: One of the jobs of your hair follicles is to produce melanin, which is the pigment that gives your hair color. As you get older, your follicles produce less pigment. This causes hairs to come in white. Usually this starts in earnest when you are in your 30s, but many people have white hairs long before then.
- Thinning and balding: As you get older, your follicles also begin producing thinner, smaller strands. So if you had thick hair when you were younger, you may notice your hair comes in finer as you get older. It may also be lighter in color (even if it still has pigment, it may have less of it). Your hair may have less volume and body and may be harder to style. You may develop bald patches. That is true whether you are a man or a woman.
Why does it happen? Genetics plays a role in determining who will go bald and when it will happen. As you age, hormonal changes are also taking place in your body. Male pattern baldness for example is usually the result when your body becomes more sensitive to androgens. In women, some diffuse thinning is quite common, but bald patches may occur in conjunction with the same types of hormonal imbalances which can cause conditions like polycystic ovary syndrome (PCOS). You can read in detail about the link between hormones, aging and hair loss here.
What Have We Learned?
To summarize, here are some of the key points we have learned about why hair grows, how it grows, and what can disrupt that growth:
- Scientists are still not sure why human beings evolved to lose their fur but grow long hair from their scalps. There are a few different theories, but none of them have a direct impact on your life (moving to a colder climate is not going to stimulate hair growth).
- Hair grows from the follicle. The bulb inside the follicle is alive, but the hair shaft is dead. This is why it is a myth that cutting your hair makes it grow faster.
- Even though the hair shaft is dead, its condition can impact the appearance and strength of your hair, so taking care of it can prevent breakage.
- Your hair will always grow at a rate of roughly an inch per month when it is healthy. This already requires cell division in the follicle to happen at an astonishing rate, so this is nothing to complain about!
- Hair growth can be disrupted by acute and chronic stressors. Once they are resolved, hair growth will generally return quickly to normal. While hair loss sometimes is indicative of a serious underlying condition, most cases of hair loss are not, and will self-resolve.
- Aging entails hormonal changes that can shrink your hair follicles. The result is that your hair gets thinner and lighter as you get older. Eventually white hairs are produced. Both men and women may develop bald patches as they get older as a result of these hormonal changes.
What You Can’t Do to Make Your Hair Grow Faster
Based on the above, here are some things that will not help your hair to grow any faster or any fuller:
- Regularly trimming it. This seems to be a myth perpetuated by hair salons that want to make more money. There is nothing about a trim every month or two that is going to speed up hair growth, which happens at the follicles, not the tips of your hair. The ends are dead.
- Shampooing your hair and rinsing it twice. I am not sure where this myth came from, but this is likely another one designed to sell products. All this is likely to do is dry out your hair. Do that and the hair shaft will become brittle and more liable to break.
- Brush your hair with 100 strokes. The origin of this myth is likewise lost on me, but if I were to hazard a guess, it is probably related in part to the trimming myth. It is again founded on this idea that your hair is somehow alive and you can stimulate it. All brushing your hair over and over does is strain the dead tissue. It is a good way to cause breakage.
- Buy products to repair split ends. Because your hair shafts are dead, they cannot “heal.” So any product that claims it can mend split ends is falsely advertising. Hair cannot grow back together at the ends.
- Sleeping with you hair down. The idea here is that your scalp needs to “breathe” for your hair to grow. Actually, it may be smarter to keep your hair up in some fashion when you sleep so that you don’t lay on it, causing tangles and breakage. Personally I do sleep with my hair “down,” but I pull it up out of the way so that it rests above my pillow instead of underneath me. My hair is long enough to do that, though, so if yours isn’t, securing it in some way is a good idea.
- Washing your hair with cold water. Depending on who you ask, this will make your hair grow faster or longer or shinier. According to chemist Mort Westman, this is simply not true at all. Something must be alive in order to react to heat or cold, so cold water has no impact on your hair shafts. Avoid really hot water though (or dry heat), as it may damage your hair or dry it out.
Care for Your Hair So It Does Not Break
One of the primary causes of confusion when it comes to hair growth myths seems to have something to do with confusing these two things:
- Hair growth
- Hair maintenance
Both are arguably equally important if what you want is a full head of long hair. You want to promote healthy, fast hair growth to keep the process in gear. But you also need to care for your hair so that it doesn’t break before reaching its full length.
For this reason, a lot of people seem to believe that what makes hair grow is taking the steps to maintain it.
The confusion is understandable. Imagine that you have relatively fast hair growth, but your hair is in poor condition and breaks readily. Because you have so many split ends and your hair breaks all the time, it never gets very long, so you assume it isn’t growing fast.
You could even know someone whose hair grows more slowly than yours, but appears to lengthen faster, because she knows how to take care of it and prevent that kind of breakage.
The following suggestions will not actually promote growth, but they will protect your hair so that it can reach its full length before entering the transitional and resting phases:
- Do not overdo the shampoo. As mentioned previously, this idea is completely off-base. Commercial shampoos are designed (on purpose) to dry out your hair so that they can sell you conditioners to fix it. Stop subjecting yourself to that cycle. If you must shampoo, try to do it only a couple of times a week. You should see immediate improvements in hair texture (I did).
- Do not overdo the hair-brushing. Do not brush your hair with 100 strokes. Once again, use as few as possible. Get the tangles out and leave it at that.
- Steer away from excess heat. Blow dryers are the worst! I have never had a problem with very hot showers, so this may only apply to dry heat, but your experiences could be different. Either way, you do not need to wash your hair in cold water to maintain it.
- Avoid chemical hair treatments, especially bleaching and permanent hair dye. Harsh chemicals will damage your hair and cause lots of breakage, frizz, and other unpleasantness. Semi-permanent dyes are not as bad, and may even have a conditioning effect. You can make an exception for henna, a natural permanent dye which is awesome for your hair.
- Don’t crush your hair. Not only should you make sure your hair is out of your way while you are sleeping, but you also should take care not to lean against it while you are sitting on the couch or in the car.
- Use natural, healthy hair care products. Choose products which help lock moisture into your hair rather than drying it out. This will help keep the hair cuticle smooth, shiny and strong.
What Can You Do to Make Your Hair Actually Grow Faster?
While there is not a lot you can do to actually speed up the rate of growth, there are a few things you can do. Here is what will make your hair grow!
Remember earlier I talked about the papilla, that little bundle of capillaries which is inside your hair follicle? The papilla delivers nutrition to your hair follicle and provides the building blocks required for cell division and growth.
That means there are at least a couple of ways that you can speed up hair growth and improve the quality of your hair directly at the root. The first is to eat a diet which provides the raw resources that your follicles need to create healthy new hair. The second is to look for ways to boost circulation in your scalp so that it is easier for nutrition to be delivered through the papilla into the follicle.
- Eat a lots of protein. Your hair shaft is made up of protein, so it makes sense to provide your follicles with the building blocks they need to make more keratin! There are numerous protein-rich foods you can add to your diet. Some great examples include whole eggs, almonds, lean chicken and beef, peanuts, and Greek yogurt. You can also try taking whey protein supplements.
- Get more omega-3 fatty acids. These can boost growth and add shine. Salmon is one of the best sources. Vegan choices include chia seeds and flaxseed. You also have the option of taking omega-3 supplements out of a bottle.
- Eat more iron. You do not necessarily need to be diagnosed with anemia to suffer hair loss relating to iron deficiency. If you are a woman, you may be extra susceptible to this issue. Women with extra heavy bleeding during their periods may end up low on iron stores for part of the month, even if through the rest of the month their iron levels are optimal. If you do think you have an iron deficiency, it is best to talk to a doctor. Taking iron pills on your own is dangerous—but one thing you can do (whether you are deficient or not) is eat more iron in your diet. Red meat, leafy green vegetables, and iron-fortified breakfast cereals are all great options.
- Make sure you are getting enough zinc. This is another nutrient that is actually vital to hair growth, so if you are not getting enough, that could be slowing your hair growth or causing thinning hair. Some of the best sources of zinc include oysters, beans, whole grains, and nuts.
- Eat cinnamon: This delicious spice can increase blood flow throughout your body, including in your scalp.
- Massage your scalp: One of the few recommendations a lot of people actually say works is a warm oil scalp massage. Use coconut oil, argan oil, or olive oil, and rub it into your scalp. Work it all throughout your hair down toward the ends and leave it in for 10-20 minutes to moisturize your hair. This works great to promote hair growth by boosting circulation and it hydrates dry hair for maintenance.
- Try inversion therapy. This is exactly what you are probably thinking it is. Basically, you just hang your head upside-down for a while (lay at the edge of your bed with your head hanging over the edge). It is usually recommended that you do it daily for around four minutes and then see if you have results after a few weeks.
- Take herbs that improve blood circulation. One example is ginkgo biloba. Studies have shown that taking ginkgo can help to open up your blood vessels. Gingko also makes blood less sticky, so the combined effect is great for promoting circulation. Another you can try is ginger, which has a blood thinning effect. Finally, a third is (possibly) cayenne pepper. Ginger and cayenne, like cinnamon, are easy to add to a variety of recipes, so integrating them into your diet is easy. With gingko, you can just take a regular supplement. You may enjoy other health benefits as well, especially during flu season. You can take herbs individually or as part of a multivitamin for hair.
So now you should be an expert in what makes your hair grow—and what doesn’t! You will no longer waste money on commercial products which cannot actually deliver, and you can instead focus on simple, inexpensive, natural methods to make your hair grow faster, longer and stronger.