Hair loss can affect both men and women and may occur for several reasons, including hormonal changes, genetics, nutritional deficiencies, stress, medical conditions, and hair-care practices. While losing some hair every day is normal, excessive shedding, gradual thinning, or noticeable bald patches may indicate an underlying issue.
Understanding the possible causes of hair loss can help you make informed decisions about hair care, nutrition, and when to seek medical advice. In this guide, we explore common causes of hair loss in women and men, along with practical ways to support healthier hair.
Table of Contents
Causes of Hair Loss in Women
Women may experience hair thinning or increased shedding because of hormonal changes, pregnancy, certain medications, nutritional deficiencies, and underlying health conditions.
1. Hormonal Changes
Hormones influence the hair growth cycle, and changes in hormone levels can contribute to hair thinning in some women.
During menopause, declining estrogen levels may coincide with changes in hair density and texture. However, menopause is not the only possible explanation for hair loss, and genetics, thyroid disorders, and other medical conditions may also play a role.
Women with polycystic ovary syndrome (PCOS) may experience thinning hair on the scalp because of increased sensitivity to androgens, a group of hormones that includes testosterone.
If hair loss occurs alongside irregular periods, acne, unusual facial hair growth, or other hormonal symptoms, a healthcare professional can help identify the cause.
2. Postpartum Hair Loss
Pregnancy changes hormone levels and often prolongs the hair growth phase. After childbirth, hormone levels shift, and more hairs may enter the shedding phase at the same time. This condition is known as postpartum hair shedding.
It commonly becomes noticeable a few months after delivery and usually improves gradually as the hair growth cycle returns to its usual pattern. However, persistent or severe hair loss may warrant medical assessment, particularly if iron deficiency or a thyroid problem is suspected.
Pregnant or breastfeeding women should consult a healthcare professional before taking hair-growth supplements, including Viviscal, because product ingredients and suitability can vary.
3. Contraceptives and Medications
Some hormonal contraceptives may contribute to hair shedding in susceptible individuals, particularly when starting, changing, or stopping a medication. The effect depends on the person’s medical history, hormonal sensitivity, and the specific contraceptive used.
Other medicines can also affect hair growth. If you notice unusual shedding after starting a new medication, speak with your healthcare professional before changing or stopping it.
4. Hair Treatments and Styling
Chemical treatments, frequent coloring, tight hairstyles, and excessive heat can weaken hair shafts and cause breakage. Some styling practices may also contribute to traction alopecia, a type of hair loss associated with repeated pulling on the hair.
Treatments such as keratin smoothing and hair glossing can change the appearance and texture of hair, but they do not necessarily treat hair loss at the follicle level. Before choosing a salon treatment, understand its ingredients, expected results, and potential risks.
For more information, read about what a keratin hair treatment can do for your hair and learn about what a hair glossing treatment is.
Causes of Hair Loss in Both Women and Men
1. Age and Genetics
Hair density and growth patterns can change with age. Some people experience gradual thinning because of hereditary hair loss, also known as androgenetic alopecia.
In men, this often appears as a receding hairline or thinning at the crown. In women, it commonly causes widening of the part or diffuse thinning across the top of the scalp.
Genetics can influence when hair loss begins, how quickly it progresses, and which areas are affected. Age-related changes alone, however, do not explain every case of excessive shedding.
2. Stress
Physical or emotional stress can disrupt the normal hair growth cycle. Significant illness, surgery, childbirth, major life changes, or prolonged stress may trigger a condition called telogen effluvium, in which more hairs than usual enter the shedding phase.
The shedding may not become noticeable until a few months after the triggering event. It is often temporary, although recovery depends on whether the underlying cause has resolved.
Hair loss itself can also cause anxiety and emotional distress. If shedding continues or becomes severe, identifying the underlying trigger is more helpful than assuming stress is the only cause.
3. Poor Nutrition and Nutritional Deficiencies
Healthy hair growth depends on adequate energy, protein, vitamins, and minerals. Restrictive diets, rapid weight loss, and deficiencies in certain nutrients can contribute to increased shedding.
Hair is primarily made of a protein called keratin. When the body does not receive enough protein or energy over time, it may prioritize essential functions over hair growth.
For more information, explore this guide on how nutrition affects hair health.
Protein
Protein provides the amino acids needed to build keratin and support normal hair growth. Good dietary sources include eggs, fish, poultry, dairy products, beans, lentils, tofu, nuts, and seeds.
There is no single protein target that is appropriate for everyone. Requirements depend on factors such as body weight, age, activity level, health status, and overall dietary needs. Consuming 150 grams of protein daily is not necessary for every person.
A balanced diet with adequate protein is generally more useful than taking high doses of supplements without identifying a deficiency.
Iron
Iron helps red blood cells carry oxygen throughout the body. Low iron stores, including iron deficiency with or without anemia, can contribute to hair shedding in some people.
Women with heavy menstrual periods, people following restrictive diets, and individuals with certain digestive conditions may be at greater risk of iron deficiency.
A healthcare professional may recommend blood tests to assess iron status when appropriate. Avoid taking iron supplements without suitable medical guidance, as excess iron can be harmful.
Zinc and Other Nutrients
Zinc supports many normal body functions, including tissue growth and repair. Deficiency may contribute to hair loss, but taking extra zinc does not necessarily improve hair growth when levels are already adequate.
Other nutrients, including vitamin D, vitamin B12, and certain essential fatty acids, may be relevant depending on a person’s diet and health status. Magnesium and other minerals are important for overall health, but supplements should not be treated as a guaranteed hair-loss solution.
Eating a varied diet that includes vegetables, fruits, whole grains, protein sources, and healthy fats can help support general nutritional needs.
4. Thyroid and Other Medical Conditions
Thyroid disorders can affect the hair growth cycle and may cause thinning or increased shedding. Autoimmune conditions, scalp infections, and certain inflammatory disorders can also lead to hair loss.
Some conditions cause diffuse shedding, while others produce distinct bald patches or inflammation of the scalp. The pattern and associated symptoms can help a healthcare professional determine which investigations may be needed.
Seek medical advice if hair loss is sudden, persistent, accompanied by scalp pain or redness, or associated with other unexplained symptoms.
5. Excessive Heat, Dyes, and Chemical Treatments
Frequent use of hair straighteners, curling irons, harsh chemical treatments, and coloring products can weaken the hair shaft, leading to dryness, split ends, and breakage.
Although hair breakage is different from hair loss originating at the follicle, the two can occur together and make hair appear thinner.
To reduce damage:
- Limit frequent high-heat styling.
- Use a heat protectant when appropriate.
- Avoid repeatedly bleaching or chemically processing the same hair.
- Choose gentle shampoos and conditioners suited to your hair type.
- Avoid tight hairstyles that repeatedly pull on the roots.
If you want to straighten your hair while reducing direct heat exposure, explore these options for straightening hair without an iron.
6. Tobacco and Smoking
Smoking is associated with adverse effects on circulation and overall health. Research has also explored links between smoking and certain forms of hair loss, although the relationship is complex and does not prove that smoking is the cause in every individual case.
Avoiding tobacco can support general health and may reduce some factors associated with poor hair and scalp health.
7. Hair Products and Styling Choices
Hair products do not usually cause follicle-related hair loss when used appropriately, but certain ingredients may irritate the scalp or cause allergic reactions in sensitive individuals.
Hair waxes, sprays, gels, dyes, and styling products should be used according to their instructions. Stop using a product if it causes persistent itching, burning, redness, or swelling.
Men who experiment with coloring or highlighting should also consider how frequently they use chemical treatments. You can explore different styles in this guide to types of hair streaks for men, while remembering that repeated bleaching and coloring may increase hair damage.
How Can You Help Prevent Hair Loss?
Not all hair loss can be prevented, particularly when genetics or certain medical conditions are involved. However, these habits can support healthier hair and help reduce avoidable damage:
- Eat a balanced diet with adequate calories, protein, and essential nutrients.
- Avoid crash diets and rapid weight-loss plans.
- Handle wet hair gently and minimize excessive brushing.
- Limit tight hairstyles and repeated chemical treatments.
- Use heat-styling tools carefully.
- Seek medical advice for persistent or unusual hair shedding.
- Avoid taking high-dose vitamins or minerals unless medically indicated.
If hair loss is ongoing, a healthcare professional may assess your medical history, scalp, medications, and nutritional status before recommending treatment.
Frequently Asked Questions
1. What is the most common cause of hair loss in men?
Hereditary hair loss, also called androgenetic alopecia, is a common cause of gradual thinning in men. It often affects the hairline and crown, although other conditions can cause hair loss too.
2. Can nutritional deficiencies cause hair loss?
Yes. Inadequate protein intake and deficiencies in nutrients such as iron or zinc can contribute to hair shedding in some people. The best approach is to identify and address the underlying deficiency rather than taking supplements indiscriminately.
3. Is postpartum hair loss permanent?
Postpartum hair shedding is usually temporary and improves as the hair growth cycle normalizes. If shedding is severe, lasts longer than expected, or occurs alongside other symptoms, seek medical advice to check for additional causes.
4. Can hair straightening and coloring cause hair loss?
Frequent heat styling and chemical treatments can damage the hair shaft and cause breakage. Tight hairstyles can also contribute to traction alopecia. Gentle styling and reducing repeated chemical processing can help minimize damage.
5. When should I see a doctor about hair loss?
Consult a healthcare professional if hair loss is sudden, persistent, patchy, or accompanied by scalp inflammation, pain, itching, or other unexplained symptoms. Early assessment can help identify treatable causes.
Conclusion
Hair loss in men and women can result from genetics, hormonal changes, stress, nutritional deficiencies, medical conditions, or damaging hair-care practices. Because these causes require different approaches, identifying the underlying reason is an important first step.
A balanced diet, gentle styling habits, and appropriate medical care can help support hair health. If you notice unusual or persistent shedding, seek professional advice rather than relying solely on hair products or supplements.