Hair loss is extremely common, but understanding why your hair is thinning or shedding is an important first step toward deciding what to do about it.
Hair loss can affect men and women at virtually any age. It may develop gradually over many years, appear as a receding hairline or thinning crown, cause diffuse thinning throughout the scalp, or sometimes occur suddenly.
There isn't one universal cause—or one solution—for every type of hair loss. Genetics, hormones, age, illness, medications, nutritional factors, autoimmune conditions and even certain hair-care practices can play a role.
Understanding the different types of hair loss can help you recognize what may be happening to your hair and when it may be time to consult a dermatologist.
What Causes Hair Loss?
Hair grows from follicles through a repeating growth cycle. When that cycle is disrupted—or when follicles gradually become smaller—the density, thickness and appearance of the hair can change.
Some of the most common causes of hair loss include:
- Genetics and family history
- Androgenetic alopecia
- Hormonal changes
- Aging
- Physical or emotional stress
- Illness or surgery
- Certain medications
- Autoimmune conditions
- Nutritional deficiencies
- Hairstyles that repeatedly pull on the hair
- Damage from certain hair-care practices
Because so many different conditions can produce similar-looking hair loss, determining the underlying cause is important before choosing a treatment.
Androgenetic Alopecia: Male and Female Pattern Hair Loss
Androgenetic alopecia, commonly called male pattern hair loss or female pattern hair loss, is the most common form of hereditary hair loss.
Genetics and sensitivity to androgens—particularly dihydrotestosterone (DHT)—play important roles in androgenetic alopecia.
In susceptible hair follicles, androgen activity can progressively shorten the hair-growth phase and contribute to follicular miniaturization. Over time, affected hairs can become shorter, finer and less visible.
Male Pattern Hair Loss
In men, androgenetic alopecia frequently appears as a receding hairline, thinning around the temples, progressive thinning at the crown or vertex, and increasingly visible scalp.
Because follicular miniaturization is progressive, identifying male pattern hair loss early can be important.
Female Pattern Hair Loss
Women can also develop androgenetic alopecia, although the pattern often looks different.
Common signs include a widening part, reduced hair density, diffuse thinning over the top of the scalp, and increasing scalp visibility.
Women experiencing unexplained or significant hair loss should consider seeing a dermatologist because hormonal changes, nutritional deficiencies, thyroid disorders and other conditions can sometimes contribute to thinning.
DHT and Hair Loss
DHT is an androgen produced from testosterone through the action of the enzyme 5-alpha-reductase.
DHT itself is not inherently harmful. However, in people genetically susceptible to androgenetic alopecia, hair follicles in certain areas of the scalp can be particularly sensitive to androgen activity.
Over time, affected follicles may miniaturize and produce progressively finer hairs.
This is why you'll frequently encounter the terms DHT, androgenetic alopecia and male pattern baldness when researching hair loss.
Hair Loss vs. Hair Shedding
Not every increase in hairs in your shower or brush means you are developing permanent hair loss.
The American Academy of Dermatology notes that shedding approximately 50 to 100 hairs per day can be normal.
Excessive shedding is often associated with a condition called telogen effluvium.
Potential triggers can include significant physical or emotional stress, major illness or fever, surgery, significant weight loss, childbirth, certain medications and other physiological changes.
The increased shedding may not begin immediately after the triggering event. It can appear months later.
Telogen effluvium is different from progressive androgenetic alopecia, although it is possible for someone to experience both.
Alopecia Areata
Alopecia areata is an autoimmune condition in which the immune system attacks hair follicles.
It often produces distinctive round or patchy areas of hair loss and can affect the scalp or other areas of the body.
Because sudden or patchy hair loss can have causes very different from ordinary pattern hair loss, it should be evaluated by a healthcare professional or dermatologist.
Can Hair Grow Back?
Sometimes.
The potential for hair regrowth depends heavily on the reason for the hair loss and the condition of the follicles.
Some forms of excessive shedding can improve after the underlying trigger resolves. Certain forms of hair loss can also respond to appropriate treatment.
With progressive androgenetic alopecia, earlier intervention may be advantageous because follicles can continue to miniaturize over time.
Minoxidil and Hair Regrowth
Topical minoxidil is one of the most established options for treating certain forms of pattern hair loss.
Minoxidil is an FDA-approved active ingredient for hair regrowth when used according to the labeling of the particular product.
Unlike medications that target androgen pathways, minoxidil does not work by reducing DHT.
Hair regrowth also takes time. Consistent use is important, and results vary from person to person.
Anyone considering minoxidil should read and follow the Drug Facts and directions for the specific minoxidil product being used.
Scalp Health and Thinning Hair
A healthy scalp provides the environment in which hair grows.
Regular cleansing can help remove excess oil, styling-product buildup and impurities from the scalp and hair. Choosing products appropriate for your hair and scalp type can also help keep existing hair looking healthy, clean and fuller.
Regenepure develops specialized hair and scalp products for people concerned about thinning hair and scalp health, including Regenepure DR Shampoo, Regenepure NT Shampoo and Regenepure Biotin Conditioner.
Cosmetic shampoos and conditioners should not be confused with FDA-approved hair-regrowth drugs. Their role is supporting scalp and hair care rather than treating or curing hair-loss disorders.
When Should You See a Dermatologist About Hair Loss?
Consider consulting a dermatologist if you experience sudden hair loss, patchy bald spots, rapidly increasing hair loss, significant scalp irritation, redness or pain, unexplained thinning, or hair loss accompanied by other physical symptoms.
A dermatologist can help determine whether the problem is hereditary pattern hair loss, excessive shedding, an autoimmune condition or another cause.
The Bottom Line
Hair loss is not one single condition.
Androgenetic alopecia, male pattern baldness, female pattern hair loss, telogen effluvium and alopecia areata have different causes and may require very different approaches.
If you are noticing thinning hair, a receding hairline, crown thinning or increased shedding, start by understanding the likely cause.
For people with hereditary pattern hair loss, recognizing the signs early and exploring evidence-based options can be particularly important.
Regardless of the cause, maintaining a consistent hair and scalp-care routine can help keep existing hair looking and feeling its best.
Frequently Asked Questions About Hair Loss
What is the most common cause of hair loss?
Hereditary pattern hair loss, or androgenetic alopecia, is the most common cause of hair loss in both men and women.
Is shedding hair always a sign of baldness?
No. Some daily shedding is normal, and excessive shedding can occur temporarily following illness, stress, surgery, childbirth, significant weight loss or other physiological changes.
Can thinning hair grow back?
It depends on the cause. Some forms of shedding can resolve, while treatments may slow hair loss or promote regrowth in some people with certain types of hair loss.
Does minoxidil help hair grow?
Topical minoxidil is an FDA-approved active ingredient for hair regrowth for specific indications and populations described on individual product labels. Results vary and continued use is generally required to maintain results.