Hair growth might seem simple, but there’s a lot happening beneath the surface. From genetics to nutrition, several factors influence how fast and thick your hair grows.
If you're struggling with hair loss or just want healthier, fuller locks, understanding the science behind hair growth is the first step.
This guide breaks down the stages of hair growth, what affects it, and the best ways to support it naturally and medically.
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The science of hair growth
Hair isn’t just about looks—it plays a role in protecting your scalp and regulating temperature. But how does it grow? The answer lies in tiny structures called hair follicles, located just beneath the skin.
These follicles go through a cycle that determines how long your hair grows, when it rests, and when it sheds.
Each hair strand is made of keratin, the same protein found in your nails and skin. Blood flow to the follicles delivers nutrients that keep your hair growing strong.
But not all hairs grow at the same time. Every follicle is on its own timeline, which explains why you don’t shed all your hair at once.
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The four stages of hair growth
Your hair goes through a continuous cycle of growing, resting, and shedding. Understanding this cycle helps explain why hair loss happens and what you can do about it.
Anagen: Growing phase
This is the phase where hair actually grows, and it lasts anywhere from two to eight years. The longer this phase lasts, the longer your hair can grow.
About 85–90% of the hairs on your head are in this phase at any given time. During anagen, hair follicles are actively producing new cells, pushing the hair strand upward.
People with long hair have follicles that stay in this phase for many years before shifting to the next stage.
Catagen: Transition phase
This is a short two-week period when hair growth slows down. The follicle shrinks, and the hair detaches from the blood supply, meaning it’s no longer growing.
Only about 1–3% of the hairs on your head are in this phase. It’s like a “cooling down” period before the hair prepares to shed.
Telogen: Resting phase
In this stage, the hair stays in the follicle but isn’t growing. This phase lasts around two to three months, and about 9–10% of your hair is in telogen at any given time.
While the old hair is resting, new hair is already forming underneath, getting ready to push the old strand out.
Exogen: Shedding phase
This is when old hair finally falls out, making room for new growth. Shedding 50 to 100 hairs per day is completely normal in this stage.
Washing and brushing often accelerate this process, but new hair is already growing in the follicle to replace what’s lost.
What affects hair growth?
Several factors can impact how fast and thick your hair grows. Some are out of your control, like genetics, while others—like diet and stress—can be managed to support healthy hair growth.
Genetics & hormones
Your genes determine a lot about your hair, including its thickness, texture, and even how long your anagen phase lasts. Some people naturally have longer growth phases, which allows their hair to grow longer before it sheds.
Hormones also play a big role, especially androgens like testosterone and its more potent form, dihydrotestosterone (DHT).
DHT can shrink hair follicles over time, leading to pattern baldness in men and some women. This process, known as androgenetic alopecia, is the most common cause of hair thinning.
Age & lifestyle
Hair growth naturally slows as you age. The anagen phase shortens, and more follicles enter the resting phase, leading to thinner hair over time.
Some people start noticing changes in their 30s or 40s, while others may experience hair thinning earlier due to genetic factors.
Your daily habits also make a difference. Smoking, for example, can reduce blood flow to hair follicles, making it harder for them to stay active.
Regular exercise, on the other hand, improves circulation and can promote healthier hair growth.
Diet & nutrition
What you eat directly affects your hair. Hair is made mostly of protein, so if your diet lacks enough of it, your strands may become weak and brittle. Key nutrients for hair growth include:
- Biotin: Supports keratin production and helps strengthen hair.
- Iron: Carries oxygen to hair follicles. Low levels can lead to shedding.
- Zinc: Plays a role in hair tissue repair and growth.
- Vitamin D: Helps create new follicles and may support hair density.
Eating a balanced diet with lean meats, eggs, nuts, leafy greens, and fish can provide the nutrients your hair needs to thrive.
Stress & mental health
Ever noticed more hair falling out during stressful periods? That’s because stress can send more hairs into the telogen phase, leading to a condition called telogen effluvium. This kind of hair loss is usually temporary, but it can be alarming.
Chronic stress may also contribute to conditions like trichotillomania (hair-pulling disorder) and alopecia areata, an autoimmune condition where the immune system attacks hair follicles.
Managing stress through activities like yoga, meditation, and exercise can help protect your hair.
Environmental & external factors
Your surroundings and hair care routine play a major role in hair health. Some of the biggest culprits behind hair damage include:
- Pollution: Toxins in the air can build up on the scalp, clogging follicles and weakening hair.
- Heat styling: Frequent use of flat irons, curling wands, and blow dryers can cause breakage.
- Chemical treatments: Hair dyes, perms, and relaxers can weaken the hair shaft and lead to thinning.
Switching to gentle hair care products, avoiding excessive heat, and using protective styles can help minimize damage and keep hair healthy.
Common causes of hair loss
Hair loss happens for many reasons—some temporary, some long-term. It can be triggered by internal factors like hormones and stress or external factors like hair treatments and environmental damage. Here are some of the most common culprits:
- Genetics – If your parents or grandparents experienced hair thinning, chances are you might too. Hereditary hair loss, also known as androgenetic alopecia, is the most common cause of hair thinning in both men and women.
- Hormonal changes – Pregnancy, menopause, thyroid disorders, and even birth control pills can throw hormone levels out of balance, leading to shedding.
- Nutritional deficiencies – Low levels of iron, zinc, biotin, and vitamin D can weaken hair follicles and cause thinning.
- Stress – Emotional or physical stress can push hair into the shedding phase too soon, leading to excessive hair loss (telogen effluvium).
- Medications & treatments – Some drugs, including chemotherapy, blood thinners, and antidepressants, list hair loss as a side effect.
- Scalp conditions – Dandruff, psoriasis, and seborrheic dermatitis can cause inflammation, making it harder for hair to grow properly.
- Overstyling & heat damage – Excessive heat, tight hairstyles, chemical treatments, and frequent coloring can weaken hair, making it prone to breakage.
Different types of hair loss
Not all hair loss looks the same. Some types happen gradually, while others come on suddenly. Understanding the type of hair loss you're dealing with can help you figure out the best course of action.
- Androgenetic alopecia (pattern baldness) – The most common type of hair loss, caused by genetics and hormones. It appears as a receding hairline and thinning crown in men and diffuse thinning in women.
- Telogen effluvium – A temporary hair-shedding condition triggered by stress, illness, or major lifestyle changes. Hair usually regrows once the underlying cause is addressed.
- Alopecia areata – An autoimmune condition where the body mistakenly attacks hair follicles, leading to patchy bald spots.
- Traction alopecia – Caused by tight hairstyles (ponytails, braids, extensions) that put excessive strain on hair follicles.
- Scarring alopecia – A rare condition where inflammation destroys hair follicles, leading to permanent hair loss.
- Hormonal hair loss – Hair loss linked to imbalances in hormones, often seen in conditions like PCOS, pregnancy-related shedding, and thyroid disorders.
Natural ways to support hair growth
If you want healthier, stronger hair, small changes in your daily habits can make a big difference. A combination of proper nutrition, scalp care, and lifestyle adjustments can help create the right environment for your hair to thrive.
Best foods for hair regrowth
What you eat directly affects how well your hair grows. Hair is made of protein, so getting enough of it is key. But that’s not all—your hair also needs vitamins and healthy fats to stay strong.
- Protein: Lean meats, eggs, fish, nuts, and dairy help build keratin, the main protein in hair.
- Iron: Found in spinach, red meat, and lentils, iron helps carry oxygen to hair follicles. Low levels can cause excessive shedding.
- Zinc: Nuts, seeds, and shellfish provide zinc, which plays a role in hair follicle repair.
- Omega-3s: Fatty acids from fish, walnuts, and flaxseeds help keep your scalp hydrated and reduce inflammation.
A well-balanced diet is one of the easiest ways to support hair health from the inside out.
Scalp care
A healthy scalp sets the stage for strong hair growth. If your scalp is dry, irritated, or clogged with product buildup, hair may struggle to grow properly.
- Scalp massage: Massaging your scalp for a few minutes each day increases blood flow to hair follicles, encouraging growth.
- Essential oils: Natural oils like rosemary, peppermint, and castor oil have been linked to improved hair growth. They can be diluted with a carrier oil and massaged into the scalp a few times a week.
- Clarifying shampoos: Using a gentle clarifying shampoo once a week can help remove excess oil and product buildup that may be blocking follicles.
Lifestyle adjustments
Your daily habits have a direct impact on your hair. Stress, lack of sleep, and smoking can all slow down hair growth, while simple lifestyle tweaks can help keep your strands healthy.
- Reduce stress: High stress levels can lead to hair shedding. Try meditation, deep breathing, or regular exercise to keep stress in check.
- Get enough sleep: Hair regenerates while you sleep, so aim for 7–9 hours per night.
- Quit smoking: Smoking constricts blood vessels, reducing circulation to the scalp and slowing down hair growth. Cutting it out can improve overall hair health.
Small changes can go a long way in keeping your hair in its best shape.
Popular home remedies
Home remedies for hair growth have been around for centuries, but do they actually work? Some have scientific backing, while others are more myth than fact.
- Aloe vera: Known for its soothing properties, aloe vera may help calm scalp irritation and promote a healthy environment for hair growth.
- Onion juice: While it smells terrible, onion juice contains sulfur, which may help strengthen hair and improve circulation when applied to the scalp.
- Rice water: Some believe rice water can make hair stronger and shinier, but scientific evidence is limited.
While these remedies may provide some benefits, they work best when combined with a solid diet, scalp care, and a healthy lifestyle.
Medical & advanced hair growth treatments
When natural remedies aren’t enough, medical treatments can step in to slow hair loss and encourage regrowth. From FDA-approved medications to cutting-edge therapies, there are several options available depending on the cause and severity of hair loss.
Minoxidil (Rogaine)
Minoxidil is one of the most widely used hair growth treatments. Originally developed as a blood pressure medication, it was found to have an interesting side effect—hair regrowth.
Applied directly to the scalp, minoxidil increases blood flow to hair follicles and prolongs the growth phase of the hair cycle.
It’s available over the counter in liquid or foam form and works best for early-stage hair loss. Both men and women can use it, but results vary.
While it won’t restore lost hair in cases of complete baldness, it can help slow shedding and encourage regrowth in thinning areas. Patience is key, though—visible improvements can take months.
Finasteride (Propecia)
Finasteride is a prescription medication that targets the root cause of male pattern baldness—DHT (dihydrotestosterone). DHT shrinks hair follicles over time, leading to thinning and eventual hair loss.
Finasteride blocks an enzyme responsible for converting testosterone into DHT, helping to preserve existing hair and even regrow some lost strands.
This treatment is primarily for men, as it can cause hormonal imbalances in women. While effective, it requires long-term use—once you stop taking it, hair loss resumes. Some men experience side effects like decreased libido, but for many, the benefits outweigh the risks.
PRP (platelet-rich plasma) therapy
PRP therapy uses your own blood to stimulate hair growth. A small amount of blood is drawn, processed to concentrate the platelets, and then injected into thinning areas of the scalp. Platelets are rich in growth factors, which can help strengthen follicles and promote healthier hair.
This treatment is popular because it’s natural—no chemicals, just your body’s own healing properties at work. Multiple sessions are needed for noticeable results, and it’s often combined with other treatments like minoxidil or finasteride for the best outcome.
While not a magic bullet, PRP is a promising option for people looking for a non-invasive way to improve hair thickness.
Stem cell therapy & exosome treatments
Stem cell therapy is one of the newest frontiers in hair restoration. It involves using stem cells to regenerate hair follicles, potentially leading to new hair growth in areas where follicles have become dormant.
Research is ongoing, but early results show promise, especially for those with thinning hair rather than complete baldness.
Exosome therapy works in a similar way, using tiny vesicles derived from stem cells to send regenerative signals to damaged follicles.
These treatments are still being developed, but they represent a potential breakthrough in long-term hair restoration. The main downside? They’re expensive and not yet widely available.
Low-level laser therapy (LLLT)
Low-level laser therapy (LLLT) uses red light to stimulate hair follicles, increasing blood flow and cellular activity. It’s available in various forms, including laser combs, caps, and in-office treatments.
The idea is that the light energy encourages follicles to stay in the growth phase longer, helping to slow hair loss and promote thicker strands.
This treatment works best for early hair thinning and needs to be used consistently over time. While it won’t regrow hair in completely bald areas, it can help maintain existing hair and improve density.
Some people find it convenient and easy to use, while others struggle with the time commitment required to see results.
Hair transplants
For those with significant hair loss, transplants offer a permanent solution. The two main techniques—FUE (Follicular Unit Extraction) and FUT (Follicular Unit Transplantation)—involve taking healthy hair follicles from the back of the head and transplanting them to thinning areas.
Transplants provide natural-looking results, but they’re not cheap. Recovery time varies, and it takes months to see full results.
Still, for people looking for a long-term fix, this is one of the most effective hair restoration options available.
Myths & misconceptions about hair growth
There’s plenty of misinformation out there about hair growth. Some myths are harmless, while others can lead to wasted time and money. Let’s clear up some of the most common ones.
Does shaving make hair grow thicker?
Shaving doesn’t change the thickness, color, or speed of hair growth. It only creates a blunt tip, making regrowing hair feel coarser for a while. Once it grows out, it’s the same as before—your genes, not your razor, determine hair thickness.
Can hair oils reverse baldness?
Hair oils keep the scalp healthy and hydrated, but they can’t regrow hair in areas where follicles are inactive. However, certain oils like rosemary and peppermint may improve circulation and support hair health—just don’t expect miracles if follicles are completely gone.
Is frequent washing bad for hair growth?
Washing your hair doesn’t cause hair loss. Shedding during shampooing is normal—it’s just hair that was already in the shedding phase. A clean scalp is actually better for hair growth since buildup from oil and products can clog follicles. The key is using a gentle shampoo suited to your hair type.
Do biotin supplements really work?
Biotin helps with hair health, but only if you’re deficient. Most people get enough from food, so taking extra won’t suddenly give you thicker hair. If you’re dealing with brittle strands, it might help, but it won’t stop genetic or hormonal hair loss.
Does stress cause permanent hair loss?
Stress can trigger telogen effluvium, where more hair sheds than usual. The good news? It’s temporary, and hair typically regrows once stress levels drop. However, chronic stress can keep the cycle going, so managing stress is key for long-term hair health.
Hair care routine for optimal growth
Caring for your hair isn’t just about appearance—it’s about keeping your scalp and strands in the best condition so they can grow strong. Here’s how to do it right.
- Choosing the right shampoo & conditioner – If your scalp is oily, go for a clarifying shampoo. If it’s dry, choose a hydrating one. A good conditioner prevents breakage and keeps hair manageable. Avoid sulfates and harsh chemicals that strip natural oils.
- How often should you wash your hair? – Oily scalps may need daily washing, while drier hair types can go longer. The goal is to keep the scalp clean without overdrying.
- Heat & chemical damage prevention – Too much heat from styling tools weakens hair over time. If you use heat, always apply a protectant. Chemical treatments like bleaching and perms also weaken strands, so spacing them out and deep-conditioning regularly helps.
- Protective hairstyles & hair care practices – Tight hairstyles like high ponytails and braids can lead to breakage (traction alopecia). Looser styles and silk or satin scrunchies help reduce tension on hair.
- Scalp massages & microneedling for hair stimulation – Massaging your scalp daily can improve blood flow to follicles, encouraging growth. Microneedling, a technique using tiny needles, stimulates follicles and is often combined with treatments like minoxidil for better results.
A holistic approach to your overall hair health
Healthy hair isn’t just about using the right shampoo or taking supplements—it’s about nourishing your scalp, supporting your follicles, and giving your hair the best environment to thrive.
A well-rounded approach includes lifestyle choices, good nutrition, and science-backed products designed to strengthen and stimulate growth.
One product that fits into this holistic approach is Bio-Pilixin Activation Serum. Developed by experts, this serum is designed to reduce hair loss and encourage growth using plant-based growth factors derived from stem cell technology.
Unlike traditional treatments, it’s drug-free and safe for daily use, making it a great option for those looking for a natural way to support their hair.
The science behind it is promising. In a clinical trial, 77% of participants noticed reduced hair loss after just 45 days, and 93% had a clinically tested reduction in hair loss after 150 days. Many users first notice less hair in the shower, often within a few weeks.
The formula includes Capilia Longa®, a natural compound linked to an 89% reduction in hair loss, niacinamide for strengthening strands, and vanillyl butyl ether, which gently warms the scalp to improve circulation.
With a 150-day money-back guarantee, it’s a well-researched, risk-free addition to any hair care routine.
Conclusion
Hair growth isn’t just about genetics—it’s influenced by everything from your diet to stress levels and scalp care. Understanding the four stages of hair growth helps explain why hair loss happens, while natural remedies, medical treatments, and good hair care practices can help keep your hair healthy.
Whether you’re looking to support growth naturally, explore advanced treatments, or simply take better care of your scalp, small changes can make a big difference.
With options like Bio-Pilixin Activation Serum, backed by clinical research, there are more ways than ever to care for your hair holistically.
At the end of the day, healthy hair starts with patience, consistency, and the right approach—because when you take care of your hair, it takes care of you.
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