Where you lose hair tells you why you are losing it.

Why is my hair thinning at the crown?

Because the follicles at the crown are genetically sensitive to a hormone called DHT, and the follicles on the back and sides of your head are not. That one difference explains the entire shape of male pattern hair loss. It is not about circulation, hats, shampoo, sleeping position, or how often you wash your hair. It is a map of which follicles inherited the receptor sensitivity and which did not.

DHT, or dihydrotestosterone, is made from testosterone by an enzyme called 5-alpha reductase. In susceptible follicles, DHT gradually shortens the growth phase of each hair cycle. The follicle does not die at once. It shrinks. Every cycle it produces a hair that is a little finer, a little shorter, a little lighter in color, until what it makes is barely more than fuzz and eventually nothing at all. Dermatologists call this miniaturization, and it is the actual event behind the word thinning.

The crown, sometimes called the vertex, sits squarely in the sensitive zone along with the temples and the front of the mid-scalp. The horseshoe band around the back and sides sits outside it. This is why almost every bald man you have ever seen is bald in roughly the same shape, and why hair moved surgically from the back of the head to the top keeps growing there. The follicle carries its DHT resistance with it. The location on the scalp is not what protects it.

That blind spot has a practical cost. Men typically notice temple recession early, because it is directly in the mirror, and notice crown thinning late. By the time the crown is obvious in ordinary lighting, a meaningful share of the follicles in that area have already been shrinking for years. Nothing about that is a reason to panic, but it is a reason to look properly rather than wait for it to become undeniable.

The Norwood pattern, explained without the jargon

Pattern hair loss follows a predictable map, and the Norwood scale is simply a set of seven reference pictures of that map. It is not a diagnosis or a grade of severity in any medical sense. It is a shared vocabulary so that two people looking at the same scalp can agree on what they are seeing and, more usefully, so that you can compare your own scalp to itself a year later.

In broad strokes, the progression goes like this. The hairline at the temples softens and moves back, producing the two shallow notches most men develop in their twenties. Separately, and often on its own schedule, a thin spot opens at the crown and slowly widens outward in a circle. Those two areas expand toward each other over years. The bridge of hair between the front and the crown is usually the last part of the top to go, and when it finally thins the two bare areas join into one. What is left is the horseshoe: the DHT-resistant band around the back and sides that persists even in men who have lost everything on top.

Three common ways it starts

• Crown first. A thin patch at the vertex with a hairline that still looks essentially intact. Common, frequently missed for years, and the presentation that responds most reliably to medication.
• Hairline first. Temples recede while the crown stays dense. Very visible early because it is directly in the mirror, and the area where treatment does the least.
• Both at once. Recession at the temples plus a widening crown, with the mid-scalp bridge thinning in between. This is the classic pattern and usually the fastest moving of the three.

Which of these you get is largely inherited, and it is not inherited from your mother's father alone. That piece of folklore comes from a real finding, that a major androgen receptor gene sits on the X chromosome, which men receive from their mother. But multiple other genes on other chromosomes contribute, so your father's hair matters too. The honest summary is that family history shifts your odds and predicts nothing precisely. Plenty of men lose hair in a pattern nobody in their family has.

One more thing the pattern tells you: pattern hair loss is progressive by definition. Left alone it does not plateau permanently and it does not reverse on its own. It can move slowly enough to look static for a few years, which is why single snapshots in time are so misleading, but the direction of travel over a decade is one way.

Diffuse thinning versus patterned thinning: what each one suggests

This is the single most useful distinction on this page. If your hair is thinning at the crown and temples while the back and sides stay thick, the pattern points strongly toward androgenetic alopecia. If your hair is thinning everywhere at once, including the DHT-resistant back and sides, the pattern points away from it and toward something else entirely. Same symptom, different cause, different workup, and often a completely different outcome.

Diffuse shedding across the whole scalp is most often telogen effluvium, in which a physiological shock pushes an abnormally large share of follicles into the resting phase at the same time. Resting hairs take roughly three months to release, so the shedding starts two to three months after whatever caused it. That delay is why people so consistently blame the wrong trigger. Telogen effluvium generally resolves over six to nine months once the cause is corrected, with no hair-specific medication involved at all.

What diffuse thinning commonly points to

• Thyroid disease. Both underactive and overactive thyroid cause diffuse hair loss. A simple blood test detects it, and hair usually recovers once levels are corrected, though the hair lags the lab numbers by months.
• Iron deficiency. Low iron stores are a recognized contributor to diffuse shedding. Ferritin is the relevant marker, and it is not included in a standard blood count, so it has to be requested specifically.
• Rapid weight loss or low protein intake. Hair is metabolically expensive and the body deprioritizes it early in a steep deficit. Shedding usually starts two to three months in and settles once intake stabilizes.
• Illness, surgery, high fever, or major stress. Any significant shock to the system can trigger it, in both directions, on the same two to three month delay.
• Certain medications. A number of common drugs list hair shedding among their effects. Never stop a prescribed medication on your own. Ask the prescriber whether an alternative exists.
• Round bare patches. Discrete, smooth, coin-shaped patches that appear over weeks are not pattern hair loss. That presentation is alopecia areata, an autoimmune condition, and it needs a clinician rather than a hair loss product.

Two complications are worth naming honestly. First, the categories overlap. It is entirely possible to have slow pattern loss at the crown and a separate episode of diffuse shedding on top of it, which is a common reason people feel like their hair loss suddenly accelerated. Second, women with pattern hair loss usually do not present with a receding hairline or a bare crown at all. The typical female presentation is a widening center part with the frontal hairline preserved, which is why the male map does not transfer cleanly. For a broader look at what does and does not grow back, see the guide on whether hair loss can be reversed.

How to tell if your hair is actually thinning

The only reliable method is comparing standardized photographs of your own scalp taken months apart. Memory is useless here, mirrors are worse, and bathroom lighting can manufacture or hide a thin spot entirely. Hair grows about half an inch a month, so nothing meaningful happens on a weekly scale. Anyone assessing their hair daily is measuring the weather, not the climate.

A photo protocol that actually works

1. 1Pick one room and one light source, ideally overhead and consistent, and use the same one every time. Never mix daylight with bathroom downlighting.
2. 2Photograph dry, clean, unstyled hair. Wet hair clumps and exaggerates scalp visibility. Product does the opposite and hides it.
3. 3Part your hair in the same place, or comb it the same way, on every single occasion.
4. 4Take four angles: straight-on hairline, top-down along the part, the crown from directly above, and one from behind. For the crown and the back, hold the phone overhead with the camera facing down, or ask someone. A second mirror works if you have one.
5. 5Repeat monthly on roughly the same date. Put the photos in a dedicated album so you are comparing images and not impressions.
6. 6Judge nothing before six months, and judge properly at twelve. Month-to-month noise is larger than month-to-month change.

Beyond photographs, a few observations carry real information. A center part that is visibly wider than it was a year ago is a genuine signal. So is scalp that becomes visible at the crown under bright overhead light when it previously did not. For men with longer hair, the diameter of a ponytail or the density at the ends is a reasonable proxy. And if individual hairs feel finer and shorter in one area than the same hairs elsewhere on your head, that difference in shaft thickness is exactly what miniaturization looks like at close range.

Counting hairs in the drain, and why it misleads

Shedding between about 50 and 100 hairs a day is normal. That number is widely misused, because nobody counts accurately and the daily figure swings enormously depending on how often you wash. Wash daily and you will see a small pile each time. Wash twice a week and you will see three days of shedding at once and conclude something is wrong. What matters is not the count on a given day but whether shedding is clearly and persistently higher than your own normal over weeks, and whether it is accompanied by visible loss of density.

The pull test, and what it does not tell you

The pull test checks for active shedding. Take about 40 to 60 hairs between your thumb and forefinger near the scalp and draw them slowly along their length with gentle, steady traction, without yanking. A few hairs coming away is normal. More than about six out of sixty, repeated in several areas, suggests a lot of follicles are in the shedding phase at once. Do it on hair that has not been washed for a day, because washing removes the hairs that were already loose and will produce a falsely reassuring result.

Here is the limitation that matters. A positive pull test points toward telogen effluvium, not pattern hair loss. Pattern hair loss usually produces a negative pull test, because the follicles are not releasing hairs in bulk, they are quietly making thinner ones. A normal pull test is not evidence that your crown is fine. It is evidence that you are not in an active shedding episode. Those are different questions, and conflating them is one of the most common self-assessment errors.

Is this normal variation, or is it actually progressing?

Normal variation is a hairline that settles back slightly in your late teens or early twenties and then stops moving, plus seasonal fluctuation in shedding. Progression is loss that keeps advancing year after year, moves into the crown, and shows up as measurably less density in the same photograph taken in the same light twelve months apart. The difference is direction over time, and nothing you can determine from a single day of looking.

The maturing hairline is worth understanding because it causes a lot of unnecessary alarm. Most men lose the low, straight, rounded hairline of childhood and settle into a slightly higher one with modest recession at the temples. It typically happens between the late teens and mid twenties, it is symmetric, it is usually modest in distance, and then it stops. A hairline that moves once and holds is maturation. A hairline that keeps moving, or one accompanied by thinning behind it at the crown, is not.

Shedding also varies through the year for many people, with a tendency toward more shedding in late summer and autumn. If your shed increases for a few weeks and then returns to baseline with no change in density, that is fluctuation. If it increases and density visibly drops and stays down, that is not.

Signals that suggest genuine progression

• The crown is visible in photographs taken this year that was not visible in photographs taken last year, under the same lighting.
• Your part has widened noticeably over months, not days.
• Hairs in the thinning area are visibly finer, shorter, and lighter than hairs from the back of your head.
• The thin area at the crown is expanding outward rather than staying the same size.
• You are styling around it, choosing different lighting for photos, or avoiding certain angles. Behavior change is often the most accurate observation anyone makes about their own hair.

One more piece of context that is easy to lose sight of. Roughly half of men have some degree of pattern hair loss by age 50, and it starts in the twenties for a substantial minority. Crown thinning at 28 is not unusual or a sign that something has gone wrong with your health. It is common, it is inherited, and the only decision it forces is whether you want to do anything about it.

What to do at each stage

The stage you are in changes the realistic goal, not the tools. Early on, the goal is keeping what you have while it is still easy. In the middle, the goal is stopping progression and recovering some of the miniaturized hair. Late, the goal is protecting the remaining density and considering whether surgical restoration makes sense. In all three cases the treatments with the strongest evidence are the same two, and any prescription requires evaluation and approval by a licensed provider.

Early: thin spot forming, density mostly intact

This is the highest-value moment and the one most men skip. Start the photo record now, because it costs nothing and it is the only thing that will let you judge treatment later. If you want to treat, this is when treatment does the most, since the objective is preventing loss rather than reversing it. Prevention works far better than recovery in this condition, and every year of untreated progression moves more follicles from the recoverable group to the permanent one.

Middle: crown clearly open, hairline receding

Finasteride is the oral option with the strongest evidence in men. It inhibits 5-alpha reductase, which substantially lowers scalp DHT and slows or halts miniaturization. Notably for this page, the pivotal trials were built around vertex and mid-scalp density, and the crown is where the drug reliably shows its best results. Side effects are uncommon but must be stated plainly: sexual side effects including reduced libido and erectile difficulty were reported by a small percentage of men in trials, and a subset of men report symptoms persisting after stopping, which remains poorly understood and is a legitimate reason for some people to decline it. Finasteride also lowers PSA readings, which matters for prostate screening, and it must not be handled by women who are or may become pregnant.

Topical minoxidil works through an unrelated mechanism, extending the growth phase of follicles you still have, and was likewise first approved on the basis of vertex regrowth. It is applied to the scalp rather than taken by mouth, it is available without a prescription, and its common downsides are scalp irritation, unwanted hair growth wherever it runs or transfers, and an increase in shedding during the first weeks that is expected and usually temporary. Low-dose oral minoxidil is prescribed off-label for hair loss by some clinicians and carries a different risk profile including fluid retention and unwanted body hair. Used together, the two medications address different parts of the problem, which is why combination treatment is common.

Late: bare scalp at the crown for years

Once an area has produced nothing for several years, the follicles there are generally gone and medication will not rebuild them. That does not make treatment pointless. The hair bordering a bald patch is still miniaturizing, and protecting it changes how the next decade looks. Surgical hair transplantation is the only approach that puts follicles into skin that no longer has any, and it is worth knowing that the crown is a demanding area for transplantation because it grows in a whorl and can keep expanding underneath the transplanted hair if the underlying process is not also being treated.

When crown thinning needs a clinician, not another article

Gradual thinning at the crown with a healthy-looking scalp is rarely urgent. Several other presentations are, because they can destroy follicles permanently while you are researching, and once a follicle is scarred over nothing brings it back. Seek an in-person evaluation promptly for any of the following.

• Discrete round or oval bare patches that appeared over weeks.
• A scalp that is red, scaly, flaking heavily, itchy, painful, burning, or developing smooth shiny areas without visible follicle openings.
• Hair loss that came on suddenly over weeks rather than gradually over years.
• Loss of eyebrow, eyelash, or body hair alongside scalp hair loss.
• Hair loss with fatigue, unexplained weight change, cold or heat intolerance, or other new symptoms, which points toward a systemic cause worth testing for.
• Diffuse thinning that clearly includes the back and sides of the head.

For ordinary pattern thinning, the value of an evaluation is a straight answer about what stage your follicles are in and whether treatment is appropriate for you. A clinician can examine the scalp under magnification and see the variation in hair shaft thickness that distinguishes miniaturization from normal density, which is not something you can assess in a mirror.

If you want to be evaluated, you can complete an online assessment. A licensed provider reviews the information you submit and decides whether any treatment is suitable for your situation. A prescription is not guaranteed, and some presentations are better handled in person. For the wider picture on male pattern hair loss and how the two main medications compare, see the male pattern hair loss guide. Nothing on this page is medical advice or a diagnosis.