Understanding Hair Growth: The Role of Nutrition, Hormones, and Hair Care Science

Hair is a biostructure shaped by many variables, including genetics, nutrition, hormones, scalp health, lifestyle, and age. Many people also experience hair loss, which leads them to look for reliable hair growth products that can help ease hair loss.

Since hair loss can be distressing for both men and women, it often feels like there’s a mystery behind those thinning strands. In reality, the biology of hair is multifactorial, and having healthy, luscious hair isn’t just a matter of luck but the result of the right nutrition, hormonal balance, routine, and a clear understanding of the science behind hair growth.

Whether you’re struggling with thinning hair, postpartum hair loss, or simply want to improve your overall hair health, this comprehensive guide breaks down everything you need to know to help you nurture healthier hair and choose effective hair growth products.

Understanding the Hair Growth Cycle

Human hair follicles don’t grow continuously; instead, they cycle through three distinct phases. These are the following: 

Anagen (Growth)

This is the longest phase, lasting 2 to 6 years for the hairs on your head. The hair follicles push out hairs that continue to grow until they’re cut or until they reach the end of their lifespan and fall out. Between 85% and 90% of hair follicles are in this growth phase.

Catagen (Transition)

This is the transitional stage of a hair follicle, and around 1% to 3% of the hairs on your head are in the catagen phase. This phase begins when the anagen phase ends and tends to last about 2 weeks. During this brief transition, cells in the follicle undergo apoptosis (programmed cell death), and the follicle shrinks.

Telogen (Rest)

This is the resting phase. Hairs don’t grow during this time, but they usually don’t fall out either. Around 10% to 15% of scalp hairs are in telogen at any time. During this phase, new hairs start to form in follicles that have just released hairs during the catagen phase.

When these phases are disrupted, it can lead to hair thinning or hair loss because when the natural balance of the hair growth cycle is disrupted, more follicles than usual can prematurely enter the telogen (resting) or exogen (shedding) phase, leading to excessive hair fall or slowed regrowth.

Factors such as stress, hormonal changes, nutrient deficiencies, illness, or aging can shorten the anagen (growth) phase or delay new hair formation, causing noticeable thinning over time. 

In some cases, like androgenetic alopecia, follicles gradually shrink, producing finer hairs with each cycle until growth slows significantly. These disruptions highlight why maintaining healthy cycles through proper nutrition, hormonal balance, scalp care, and evidence-based treatments is key to preventing hair loss and supporting stronger regrowth.

Nutrition: Fueling Hair from Within with Key Vitamins and Minerals

Think of your hair like the gardens of Babylon, it needs the right care and nutrients to grow lush and beautiful. The food and water we consume have a huge impact on how our hair looks and feels, and most of us don’t even realize it. We’ve got to break down the right nutrition your hair needs to help you achieve gorgeous, shiny, and healthy hair.

Patients with hair loss often inquire whether nutritional supplements can help restore hair growth or prevent further hair loss. In fact, many start dietary supplements without consultation, hoping that good hair supplements will help and many brands capitalize on this population’s vulnerability. Let’s check the key vitamins and minerals you need to properly balance to impact both hair structure and healthy hair growth:

Protein 

Protein not only contributes to one’s physical appearance, but it also contributes to the hair’s bounce, sheen, and fullness. Protein is the foundation of healthy hair, as hair is primarily composed of keratin, a structural protein. When your diet lacks sufficient protein, your body redirects available protein toward vital functions like organ repair, leaving hair follicles undernourished. This can cause increased shedding, slower growth, or hair that becomes dry and brittle.

Consistent protein intake supports the growth and strength of new hair strands. Eating foods such as lean meats, poultry, fish, eggs, dairy, tofu, legumes, quinoa, nuts, and seeds can help address deficiencies that lead to weakened follicles and premature shedding. Making sure you adequately consume protein helps maintain strong, growing hair during the anagen (growth) phase.

Amino Acids

Amino acids are the building blocks of protein, and certain types are especially important for hair health. Cysteine, methionine, lysine, and arginine which each play key roles in forming keratin and supporting follicle structure. 

Cysteine and methionine are sulfur-containing amino acids that give hair its strength and shape. While, lysine supports collagen formation around hair follicles and improves iron uptake, both of which are crucial for growth.

Meanwhile, arginine enhances blood flow to the roots, ensuring follicles receive essential nutrients. Even if you consume enough protein, low levels of specific amino acids can affect hair strength, growth rate, and resilience.

Iron

Iron enables red blood cells to carry oxygen to hair follicles, fueling their growth. In fact, iron deficiency (ID) is the world’s most common nutritional deficiency and a well-known cause of hair loss. It shortens the anagen phase and pushes more follicles into the telogen phase, leading to shedding.

Low iron is common, especially in women, and is a major cause of diffuse hair loss. To avoid this, include iron-rich foods such as red meat, liver, poultry, lentils, beans, spinach, and fortified cereals in your diet. Pair these with vitamin C-rich foods to improve iron absorption.

Zinc

Zinc supports tissue growth, cell division, and protein synthesis. It helps follicles transition smoothly through growth phases and regulates sebum production, which keeps the scalp healthy and supports consistent hair growth. 

Good sources of zinc include oysters, beef, pumpkin seeds, lentils, cashews, and eggs. These foods promote the growth and repair of hair tissue by synthesizing the protein keratin.

Omega-3 Fatty Acids

Omega-3s nourish the scalp, improve circulation, and reduce inflammation. While they don’t directly trigger new hair growth, they create an optimal environment for follicles. You can find omega-3 fatty acids in salmon, mackerel, sardines, chia seeds, flaxseeds, walnuts, and algae-based supplements.

Omega-3s support stronger, shinier, and more resilient strands by keeping the scalp hydrated and healthy. Additionally, they nourish hair follicles, improve scalp circulation to deliver nutrients, and reduce inflammation that can cause hair loss. They also help maintain scalp moisture to prevent dryness and brittleness, which is why it’s important to include fish oil as support for hair health.

Vitamins 

A well‑rounded diet provides the micronutrients hair needs. Scientific reviews point out that:

1. 1. Vitamin D helps regulate hair follicle cycling. Women with telogen effluvium or female pattern hair loss tend to have lower serum vitamin D2 levels. Foods like fatty fish, fortified dairy and controlled sunlight exposure support vitamin D production.

   2. Vitamin A is necessary for cell growth but is a double‑edged sword: deficiency isn’t commonly linked to hair loss, yet excessive supplementation can trigger shedding. So, balance is key here.

   3. Vitamin E, an antioxidant, is usually sufficient in the diet; high doses may decrease thyroid hormone and impede hair growth.

   4. Biotin deficiency is rare, but severe shortages can cause alopecia. In addition, folate and other B vitamins support healthy cell growth and should be consumed through leafy greens, whole grains, and legumes to help maintain strong, healthy hair.

   5. Antioxidants such as selenium, vitamin C, and carotenoids combat oxidative stress. Evidence suggests oxidative stress can damage hair follicles.

Health institutions advise that most people get these nutrients from food; high-dose supplements should only be taken when laboratory testing confirms a deficiency. Practicing a balanced diet with fruits, vegetables, lean proteins, and whole grains typically provides adequate levels.

Through the help of a nutritionally healthy and balanced diet, you can keep your hair strong and shiny. But remember, too much of certain vitamins and minerals can be harmful, so balance is the key. Excessive intake can lead to toxicity, cause hair splits and damage, and, in the worst cases, affect thyroid function and certain hormone levels.

Effects of Hormones and Endocrine Disorder on Hair Growth

The hormones produced by your thyroid also play an important role in hair growth and hair loss. Hormonal balance is fundamental to hair health. Androgens, particularly dihydrotestosterone (DHT), bind to receptors in dermal papilla cells and influence hair follicle size. 

In androgenetic alopecia (also called male or female pattern hair loss), some hair follicles become extra sensitive to a hormone called DHT. DHT comes from testosterone, which is changed into DHT by an enzyme in the body called 5-alpha reductase.

When there’s too much DHT, it slowly makes the hair follicles shrink, which means they grow shorter and thinner hairs over time. As the follicles keep shrinking, the hair becomes finer, weaker, and may eventually stop growing in those areas.

Additionally, women with polycystic ovary syndrome (PCOS) often have elevated androgen levels, and studies estimate that about 22% to 30% of women with PCOS show signs of androgenetic alopecia (female pattern hair loss). In these cases, the excess androgens (including testosterone) convert more easily into DHT, which then binds to sensitive hair follicles and triggers miniaturization (shrinking) of follicles. Over time, this leads to thinner, shorter hairs and accelerated hair thinning on the scalp.

Because PCOS also often involves insulin resistance, elevated insulin can stimulate the ovaries to produce yet more androgens, further fueling this process Dr. Jolene Brighten said. Thus, hair loss in PCOS is often part of a broader pattern of hormonal imbalance, and managing those systemic factors (insulin, androgens) is just as important as treating the hair directly.

Other Hormones That Influence Hair Growth

While androgens like DHT are major players in hair loss and growth patterns, they’re not the only hormones involved. The hair growth cycle is also influenced by a complex network of endocrine signals, including thyroid hormones, estrogen, and cortisol. 

These hormones affect how long hair stays in its growth phase, how quickly it sheds, and the overall health of the scalp and follicles. When these hormones become imbalanced, whether  due to stress, medical conditions, or natural life changes, they can disrupt the hair cycle, leading to thinning, brittleness, or increased shedding.

• Thyroid Hormones: 

Your thyroid hormones regulate your body’s metabolism, essentially controlling how your body uses energy. Because hair growth depends on a steady supply of energy and nutrients, thyroid function directly affects the speed, quality, and density of hair growth.

1. 1. Hypothyroidism (underactive thyroid): When the thyroid produces too little hormone, the body’s processes slow down. This can cause diffuse hair thinning across the scalp, meaning the hair becomes sparse rather than receding in specific patches.
   2. Hyperthyroidism (overactive thyroid): When the thyroid produces too much hormone, the hair growth cycle speeds up unnaturally. This can lead to brittle, weak hair and increased shedding, as follicles move through growth phases too quickly.

• Estrogen

Estrogen plays a protective role in hair health. It prolongs the anagen (growth) phase, allowing hair to grow longer, thicker, and stay in the scalp for extended periods.

When estrogen levels decline such as during menopause, postpartum changes, or certain medical conditions, many women notice increased shedding and a pattern of thinning similar to female pattern hair loss. This happens because the growth phase shortens, and androgens become more dominant, which can lead to hair miniaturization and loss over time.

Supporting estrogen balance through medical consultation and lifestyle adjustments can help stabilize hair growth during these hormonal transitions.

• Cortisol (Stress Hormone):

Cortisol is the hormone your body releases in response to stress. Chronic stress keeps cortisol levels elevated for long periods, which can negatively affect hair growth.

A Harvard study found that high cortisol levels can prolong the telogen (resting) phase by preventing dermal papilla cells from secreting Gas6, a molecule that activates hair follicle stem cells. Without Gas6, follicles remain “stuck” in their resting phase, leading to slower regrowth and increased shedding.

When researchers reduced stress hormones in mice, resting phases shortened, and hair growth improved. This helps explain why ongoing stress often contributes to temporary hair loss, a condition known as telogen effluvium, where more hairs than usual shed a few months after a stressful event.

Managing stress through sleep, exercise, mindfulness, or medical support plays a critical role in maintaining a healthy hair growth cycle.

Why Hormonal Understanding Matters

Hormones play a central role in regulating hair growth, which is why understanding their effects is key to choosing the right treatment. One of the main hormones involved is dihydrotestosterone (DHT), which can shrink hair follicles and shorten the growth cycle, leading to thinning over time. Many medical treatments directly target these hormonal pathways. For example, finasteride blocks the enzyme 5-alpha reductase, reducing DHT production, while spironolactone limits the activity of androgens on hair follicles. By correcting hormonal imbalances alongside maintaining good nutrition and proper hair care, you can support healthier hair growth, increase density, and slow down further loss.

Key Takeaway

Hair growth is influenced by a web of factors, but mostly by nutrition and hormones. By understanding the science behind the hair cycle, what it needs at each stage, and especially how hormones influence hair growth, men and women can take proactive steps to support their locks.

Healthy hair growth isn’t a matter of luck; it’s the result of a balanced approach that includes the right nutrition and hormonal support. You can make smarter choices to support stronger, healthier, and more resilient hair when you understand your hair better.

Whether you’re experiencing thinning, hormonal changes, or simply want to boost your hair’s vitality, a science-backed routine lays the foundation for lasting results. You can also turn to hair growth products that are backed by natural ingredients, care for your scalp, and integrate evidence-based treatments. Hair growth products like those from EZZ DNA can be helpful tools, but they work best when combined with healthy habits and professional guidance.

Remember, consistency and patience are key. Hair follicles need time to respond to change, but with the right strategy, regrowth and healthier hair are within reach.

Spotlight on EZZ DNA Hair Growth Products

Once you understand how hormones influence hair health, the next step is choosing a solution that works with your body, not against it. EZZ DNA Hair Growth Products are designed to do exactly that. Backed by science and trusted by Australians nationwide, EZZ products target the root causes of hair thinning to deliver visible, lasting results.

What sets EZZ apart is its advanced, nutrient-rich formulations that work on multiple levels:

• Nourish the scalp to create the ideal environment for new growth.

• Strengthen hair follicles to reduce breakage and improve density.

• Support natural growth cycles to encourage fuller, healthier hair over time.

Rather than offering a quick fix, these products focus on long-term scalp and follicle health, creating the ideal conditions for thicker, stronger, and more resilient hair. EZZ’s commitment to the quality and efficacy of their hair growth products has made it a trusted choice for Australians seeking a premium, results-driven hair care solution.

Whether you’re managing hormonal changes, dealing with everyday stress, or noticing early signs of thinning, EZZ offers a smart, effective way to bring vitality back to your hair. With consistent use, you can expect stronger strands, improved scalp health, and renewed confidence in the way your hair looks and feels.

From root to tip, EZZ helps you achieve healthier, fuller hair, and the confidence that follows!