Why Is My Hair Falling Out? How to Tell Which Type You Have

Reviewed by Dr Eugene Lim | MBBS, General Practitioner in Aesthetic and Lifestyle Medicine, Dr Cindy’s Medical Aesthetics, Singapore.

Hair loss can be grouped into several broad categories, and understanding which pattern yours resembles can help determine what to do next. Some types of hair loss recover on their own, some require an underlying medical cause to be addressed, while others tend to progress without treatment. You can begin looking for these clues at home, although confirming the cause may require a medical assessment.

This distinction matters because different types of hair loss need different approaches. A shedding episode after an illness, for example, will often resolve once the trigger has passed. Pattern hair loss, by contrast, tends to progress without treatment and is generally easier to manage when recognised earlier.

Hair loss associated with conditions such as iron deficiency or thyroid dysfunction may improve only when the underlying problem is addressed, regardless of what is applied to the scalp. Without identifying the cause, it is easy to spend months trying interventions that do not address the actual problem.

This article explains what normal shedding looks like, the difference between shedding and thinning, four common patterns of hair loss to look for, and some of the causes behind them. It is a starting point for understanding what may be happening and when a medical assessment is appropriate.

First, how much hair loss is normal

Everyone sheds hair every day as part of the normal hair cycle.

Each follicle on your scalp cycles through a growth phase, a short transitional phase and a resting phase, after which the hair is eventually released and shed. Because your follicles are not synchronised, a proportion of your hairs are always reaching the shedding stage.

A commonly quoted figure is around 50 to 100 hairs a day, but treat this as a rule of thumb rather than something you need to count. What matters more is whether your shedding has clearly changed from what is normal for you.

Normal shedding tends to remain relatively consistent over time, although the amount you notice can vary depending on how often you wash or brush your hair.

Three changes make hair loss worth paying closer attention to:

The amount has clearly increased and stayed increased. You are consistently seeing more hair in the drain, on your pillow or in your brush than you normally would, rather than noticing more after a single wash.

The density has visibly changed. Your part appears wider, more scalp is visible than before, or your ponytail feels noticeably thinner.

The loss is patchy rather than diffuse. Distinct circular or oval areas of hair loss are different from generalised shedding or thinning and should be assessed separately.

A brief increase in shedding without any visible loss of density may settle on its own, particularly if there has been a recent trigger such as illness. If the shedding persists, is substantial or worsening, or you notice a change in density, patchy hair loss or scalp symptoms, it is worth having the cause assessed.

Shedding and thinning are not the same problem

This is the distinction that does the most diagnostic work, and it is the one most often collapsed.

Shedding is about how much hair is coming out. The hairs that fall are typically full-length and normal in thickness.

You see them, in quantity, and it is frightening. But the follicles are still capable of producing normal hair; more of them have been pushed through the hair cycle at the same time, so unusually large numbers are being shed.

Thinning is about the quality of what grows back. The overall volume decreases while daily fall may look completely unremarkable.

The hairs that regrow are progressively shorter, finer and less pigmented than the ones they replaced. Nothing dramatic happens in the shower, and yet over two or three years the coverage can change substantially.

The practical check is to look at the hairs themselves. Take a few from the pillow or the brush and compare them.

If they are mostly uniform and normal in calibre, and there are many of them, the picture is more consistent with shedding. If you can see a clear mix – some normal hairs and some noticeably finer, shorter, wispier ones – the picture suggests thinning, and those finer hairs can be a sign that the follicles are miniaturising.

Patients often come in about shedding, because shedding is visible. Thinning is the one that quietly takes ground.

The four types, and how to recognise yours

Pattern hair loss, or androgenetic alopecia

Hereditary and hormonally driven, and by some distance the most common. It follows a recognisable distribution rather than affecting the whole scalp equally.

In men it typically begins at the temples and the hairline, moving back, and separately at the crown. These areas may gradually enlarge and, in more advanced cases, eventually meet.

In women the presentation is different and this is a frequent source of confusion: the frontal hairline is usually preserved, and the loss shows as a widening part and diffuse thinning across the top of the scalp. Female hair loss is covered separately, because the causes that get missed are different. Many women expect a receding hairline, do not have one, and conclude they cannot have pattern hair loss.

How to check. Part your hair down the middle in good light and photograph it. Then compare it against a photograph from two or three years ago in similar lighting.

Pattern loss is gradual enough that memory is unreliable, which is why photographs are useful. What you are looking for is the part widening, the scalp becoming more visible at the crown, and finer hairs mixed in among normal ones.

It is progressive, so it tends to continue without intervention. That single fact is why timing matters in this category, and what a doctor can actually do about it generally has more to work with when pattern hair loss is caught early.

Shedding, or telogen effluvium

Sudden, diffuse, heavy shedding across the whole scalp, often arriving two to three months after a trigger. The delay is an important diagnostic clue and it is why patients so often report that the shedding came out of nowhere. The trigger has often been forgotten by the time the hair falls.

Common triggers include a significant illness with fever, surgery, childbirth, rapid or substantial weight loss, severe psychological or physiological stress, or starting or stopping certain medications.

How to check. Count backwards about three months from when the shedding started and ask what happened then. A significant illness, operation, major weight change or other clear trigger makes telogen effluvium more likely. The outlook is usually good: the follicles are not permanently damaged, and once the trigger has resolved the hair cycle can gradually return to normal.

Nutritional, hormonal and medical

Here the hair loss is a symptom of something systemic rather than primarily a scalp condition. Iron deficiency is an important cause to look for, insufficient protein intake matters, and thyroid dysfunction in either direction can cause diffuse hair loss.

Hormonal transitions change the picture too, particularly after childbirth and around menopause. The clinic also sees shedding following Covid infection, usually in the form of telogen effluvium.

How to check. You cannot reliably establish this from home, and this is the point. The scalp gives no reliable clue as to whether your iron stores are low or your thyroid is abnormal, and blood tests may be needed depending on the history. What should prompt suspicion is hair loss alongside fatigue, unusual cold or heat intolerance, unexplained weight change, heavy periods, a restrictive or recently changed diet, or a recent significant illness.

Nothing applied to the scalp substitutes for correcting an underlying medical cause. Where treatment is appropriate, the options are set out in the guide to hair loss treatment in Singapore.

Scalp and inflammatory conditions

Alopecia areata, scalp infections and inflammatory scalp disease. The distinguishing feature is that the scalp itself is symptomatic or visibly abnormal, rather than simply being the place where hair is thinning.

How to check. Persistent itch, flaking, tenderness, soreness, visible scaling, or patchy loss with well-defined circular borders. Any of these belongs in this category.

There is a point specific to this population. In Fitzpatrick III to V skin, which covers most Chinese, Malay, Indian and wider Southeast Asian patients, scalp redness is far less obvious than it is in lighter skin. Inflammation that would be immediately visible in a pale scalp can be easy to miss here, which is one reason this category is more reliably identified on close examination than from a photograph or a glance in the mirror.

What actually causes each of them

Genetics, and which parent it comes from

Pattern hair loss is inherited, but the belief that it comes from your mother’s father specifically is a simplification of something polygenic. Susceptibility is influenced by variants inherited from both sides of the family.

A father with heavy pattern loss is a meaningful signal and so is a mother with a visibly widening part. Neither settles it in either direction.

What you inherit is, in part, how sensitive your follicles are to androgens. In susceptible follicles, each successive growth cycle produces a shorter and finer hair, which is miniaturisation.

At first the follicle survives and simply produces less with each cycle. This is why treatment works better early: a miniaturised follicle still has more potential to respond than one that has been severely miniaturised for years.

Stress

Sustained physiological or psychological stress can cause hair loss through the shedding mechanism, and that distinction matters because the outlook is completely different. A significant stressor can push a larger proportion of follicles out of the growth phase at around the same time, with increased shedding appearing two to three months later. Hereditary pattern loss has a separate cause, and telogen effluvium does not permanently damage the follicles.

The confusion arises because stress is common and pattern hair loss is common, so they frequently coincide. Someone under strain who is also in the early years of pattern loss may attribute all of it to stress and wait for it to pass.

The shedding component will usually pass once the trigger has resolved. The pattern component will not.

Nutritional deficiency, and which one

Iron deficiency is one of the first nutritional causes to consider. Ferritin is useful because it reflects iron stores, which can be depleted even while haemoglobin and a full blood count remain normal. Insufficient protein intake matters too, because hair is largely made of protein.

Vitamin D deficiency is associated with several forms of hair loss, although an association does not necessarily mean it is the cause in an individual patient. Zinc deficiency can also cause hair loss, but genuine deficiency is less common.

Biotin deserves a direct answer, because it is the ingredient most heavily marketed for hair. Biotin deficiency can cause hair loss, and correcting a genuine deficiency is appropriate. Biotin deficiency is also rare in people eating an ordinary balanced diet.

Supplementing above requirement in someone who is not deficient does not produce more hair, for the same reason that watering a plant that is not thirsty does not make it grow faster. Which hair supplements actually work goes through the evidence by mechanism. It is worth knowing that high-dose biotin can also interfere with several laboratory blood tests, including some thyroid tests, so tell your doctor if you are taking it before bloods are taken.

Thyroid problems

Both an overactive and an underactive thyroid can cause diffuse hair loss because thyroid hormones influence the hair growth cycle. The hair loss is typically diffuse rather than patterned, and it may be accompanied by other symptoms: changes in weight, energy, temperature tolerance, bowel habit or menstrual pattern.

Hair growth usually improves once the thyroid disorder is adequately treated, although recovery takes time. That is precisely why this category has to be identified rather than treated over.

Does creatine cause hair loss

This question has real currency and deserves a straight answer. The concern traces largely to a small study in rugby players which found an increase in dihydrotestosterone, or DHT, in the group taking creatine. DHT is one of the androgens involved in pattern hair loss.

That study did not measure hair loss at all. More importantly, a subsequent randomised controlled trial that directly measured both hormone levels and hair outcomes found no significant difference in DHT or hair growth measures between men taking creatine and those taking a placebo.

The evidence we have does not show that creatine causes hair loss. If you are already genetically susceptible to pattern hair loss, that susceptibility still exists whether or not you take creatine, but there is currently no good evidence that creatine accelerates it. Stopping creatine is not a treatment for pattern hair loss that has already started.

Traction, and the hairstyles that cause it

Sustained pulling on the follicle causes traction alopecia, and unlike many other causes of hair loss it is preventable and can be reversible in its early stages. Tight ponytails, tight braids, buns worn in the same position daily, and hair extensions are common causes. The distribution is the clue: loss along the hairline, at the temples, or in an area corresponding to where the tension sits.

Caught early, it can recover once the tension is removed. Sustained for long enough, it may stop recovering because chronic traction can eventually scar the follicle. Helmets are frequently blamed and are unlikely to cause traction alopecia on their own, though a helmet worn over tightly tied hair can add to the tension.

Itchy or flaky scalp

An itchy, flaking scalp can affect the hair indirectly. Dandruff and seborrhoeic dermatitis cause scalp inflammation, while persistent scratching can damage the hair shaft and contribute to breakage.

The important point is that treating the scalp condition and treating significant hair loss are not necessarily the same thing. Settling the itch, scaling and inflammation improves the health and comfort of the scalp, but it will not by itself reverse pattern hair loss or correct an underlying medical cause. If both are present, both need to be addressed.

What Singapore adds

Generic hair loss advice is often written for temperate climates, and it does not always describe the conditions a scalp faces here.

Singapore is hot and humid throughout the year. Heat, humidity and sweating do not directly cause pattern hair loss or telogen effluvium, but they can make an oily, itchy or flaky scalp more noticeable and can aggravate existing scalp conditions in some people. Frequent sweating may also mean washing the hair more often, and repeatedly using harsh or strongly clarifying shampoos can irritate an already sensitive scalp.

To be clear about the mechanism, because it is often overstated: humidity and heat do not cause hair loss. They can, however, make an existing scalp problem more uncomfortable and more difficult to manage.

The ultraviolet index here also regularly reaches very high to extreme levels. A thinning scalp has less protection from the hair above it, and a widening part exposes more skin directly to ultraviolet radiation. That is a skin-health issue rather than a cause of the hair loss itself, and it is worth knowing about.

Three things patients commonly get wrong

Washing your hair less will reduce hair loss. It will not stop hairs that have already entered the shedding phase from coming out. Washing less can simply concentrate those hairs into fewer, more alarming wash days. If the scalp is oily, itchy or affected by dandruff, reducing washing may also make the scalp symptoms harder to manage.

Hair loss at a young age means something is seriously wrong. Pattern hair loss can begin in the late teens or twenties and frequently does. On its own, it is not a sign of ill health. What an early start does mean is that there is more time for it to progress, which makes early assessment more valuable, not less.

You should wait and see whether it stops on its own. This can be reasonable for a short-lived shedding episode after a clear trigger, but it is poor advice for progressive or unexplained hair loss. The useful move is to establish what type of hair loss you are dealing with first, and then decide whether waiting is appropriate.

When to have it assessed, and what happens

Have it looked at if heavier shedding is persistent, substantial or getting worse. Also if your part is widening or your hairline is moving, if the loss is patchy, or if your scalp is persistently itchy, sore or scaling. Hair loss alongside fatigue, unexplained weight change or unusual cold or heat intolerance is worth assessing too.

The clinic’s hair loss and thinning assessment starts with a detailed history: onset, duration, pattern, family history, recent illnesses, medications and lifestyle factors. That history often gives important clues to the category, because a sudden shed a few months after an illness and three years of gradual thinning are very different stories before anyone looks at your scalp.

It is followed by a physical examination of the scalp and hair, assessing distribution, pattern and extent, and checking the scalp for inflammation, infection or dermatological conditions. Where the history and examination point to a systemic cause, further investigations such as blood tests may follow.

You should leave with a clearer understanding of which category you are in, whether there is an underlying cause to correct first, and whether waiting is reasonable in your case. What treatment options follow from that is a separate conversation, and it is a much shorter one once the category is settled.

Where to be seen, and who sees you

Dr Cindy’s Medical Aesthetics assesses hair loss at both clinics.

Orchard. 360 Orchard Road, #05-06 International Building, Singapore 238869. Monday and Thursday 11.30am to 7pm, Tuesday, Wednesday and Friday 10am to 8pm, Saturday 10am to 3pm. Closed Sunday and public holidays.

Tampines. 1 Tampines Central 5, #07-01 CPF Tampines Building, Singapore 529508. Monday to Friday 11.30am to 9pm, Saturday 10am to 7pm. Closed Sunday and public holidays.

Assessments are carried out by Dr Cindy Yang, founder and medical director, Dr Eugene Lim, fully registered with the Singapore Medical Council, and Dr Grace Su, a general practitioner working in aesthetic and lifestyle medicine.

Where it is not us: patchy loss with well-defined circular borders, a painful or blistering scalp, or rapidly spreading scalp disease warrants dermatological assessment and possibly a scalp biopsy. A referral is the correct outcome of a consultation in those cases, and worth saying plainly so that nobody delays seeing the right person.

Knowing which of the four you have changes what you should do next, and in two of the four it changes whether you need to do anything at all. That is the whole reason to start with the diagnosis rather than the product.

Frequently asked questions

Why is my hair falling out?

It will be one of four things: pattern hair loss, which is hereditary, hormonal and progressive; telogen effluvium, a shedding episode two to three months after an illness, childbirth, surgery, weight loss or severe stress; a nutritional, hormonal or medical cause such as low ferritin or thyroid dysfunction; or a scalp and inflammatory condition. The distribution, the timeline and the calibre of the hairs coming out distinguish them.

How much hair loss is normal in a day?

Around 100 hairs a day is the usual rule of thumb, but the change matters more than the count. Normal shedding is stable over years. A clear, sustained increase, or any visible change in density, is what warrants assessment.

What are the different types of hair loss?

The four groups above. Within pattern hair loss, presentation differs by sex: men typically recede at the temples and thin at the crown, women typically keep the frontal hairline and develop a widening part with diffuse thinning on top.

How do I know if my hair loss is temporary or permanent?

Look at what triggered it and at the calibre of the hairs. Diffuse shedding of normal-thickness hairs starting two to three months after an identifiable trigger is usually temporary. A gradual change in density with visibly finer hairs mixed in, following a recognisable pattern, is progressive and will not resolve on its own.

What is the difference between hair shedding and hair thinning?

Shedding is how much comes out and the hairs are normal in thickness. Thinning is a decline in the quality of what grows back, with progressively finer and shorter hairs, and daily fall can still look normal. Shedding is what patients notice; thinning is what changes coverage.

How can I tell if I have androgenetic alopecia?

The pattern and the presence of finer hairs among normal ones. Photograph your part in good light and compare it with a photograph from two or three years ago. A widening part, increasing scalp visibility at the crown, or a receding temporal hairline in men, combined with mixed hair calibre, points to pattern hair loss. Examination confirms it.

What is telogen effluvium and how long does it last?

A shedding episode caused by a systemic shock that pushes an unusually large share of follicles out of the growth phase at once. It appears two to three months after the trigger and typically settles within several months of the trigger resolving. The follicles are not damaged, so the outlook is good, though regrowth follows the growth cycle and cannot be hurried.

Is my hairline receding or is that just my natural hairline?

Photographs settle it and memory does not. Compare against an older photograph in similar lighting. A genuinely receding hairline moves back at the temples first and is usually accompanied by finer hairs at the margin. Some hairlines simply sit high and have always done so.

What does the early stage of pattern hair loss look like?

Rarely a bald patch. It is a widening part, more scalp visible under bright or overhead light, a ponytail that feels thinner to hold, and hairs of visibly different thickness in the same area. Daily shedding is often completely normal at this stage, which is exactly why it gets missed.

Should I be worried about hair loss at my age?

Pattern hair loss commonly begins in the twenties and can begin in the late teens, and it is not a sign of poor health. Starting young does mean more years for it to progress, which makes establishing the category early more useful rather than less.

What causes hair loss?

Four groups of cause. Heredity and androgen sensitivity produce pattern hair loss. A systemic shock, illness, surgery, childbirth, rapid weight loss or severe stress, produces telogen effluvium two to three months later. Nutritional and medical causes include low ferritin, insufficient protein, vitamin D deficiency and thyroid dysfunction. Scalp and inflammatory conditions include alopecia areata and inflammatory scalp disease. Traction from tight hairstyles is a fifth, preventable cause. Which one you have determines whether it recovers on its own.

Can stress cause hair loss?

Yes, through telogen effluvium, appearing two to three months after the stressful period and resolving once it passes. Stress does not cause hereditary pattern hair loss. Where both are present, the stress-related shedding settles and the pattern component continues.

Which vitamin deficiency causes hair loss?

Iron is the most common, measured as ferritin rather than haemoglobin, because ferritin can be low enough to affect hair while a full blood count reads normal. Vitamin D deficiency is associated with hair loss and is common here. Zinc deficiency is a genuine but less common cause. Biotin deficiency does cause hair loss but is rare on an ordinary diet, so supplementing biotin without a deficiency does not add hair.

Does creatine cause hair loss?

The evidence is weak and indirect. It rests on one small study that found raised dihydrotestosterone in creatine users and did not measure hair loss. No trial has shown creatine causing hair loss. If you are already susceptible to pattern hair loss the theoretical mechanism is worth knowing about, but stopping creatine will not treat pattern loss that has begun.

Can thyroid problems make your hair fall out?

Yes, in both directions, because thyroid hormone regulates the growth cycle. The loss is usually diffuse rather than patterned and usually comes with other symptoms such as weight, energy, temperature or menstrual changes. It improves when the thyroid is treated, which is why it needs identifying rather than treating over.

Does Singapore’s humidity and heat make hair loss worse?

Not directly. Humidity and heat do not cause hair loss. What they do is drive sweat, frequent washing and barrier disruption that produce scalp inflammation, and an inflamed scalp makes existing hair loss worse and other treatments less effective.

Can tying your hair tightly or wearing a helmet cause hair loss?

Tight ponytails, braids, daily buns and extensions cause traction alopecia, recognisable by loss along the hairline or wherever the tension sits. Early it recovers once the tension is removed. Sustained for years it scars, and at that point it no longer recovers. A helmet alone is rarely the cause, though a helmet over tightly tied hair adds to the tension.

Does an itchy or flaky scalp cause hair loss?

Not directly, but it matters. Inflammation creates a poorer environment for the follicle and scratching causes breakage. Treating it will not resolve significant hair loss on its own, and leaving it untreated makes everything else work less well, so it is dealt with first.

Can low iron or low ferritin cause hair thinning?

Yes, and it is one of the more commonly missed causes because a standard full blood count can be normal while ferritin is low. If hair loss coincides with fatigue, heavy periods or a restrictive diet, ferritin is worth testing specifically.

Is hair loss inherited from your mother or your father?

Both. The idea that it comes from the maternal grandfather is a simplification of a polygenic trait. What is inherited is how sensitive your follicles are to androgens, and variants from either side contribute.

References

1. van der Merwe J, Brooks NE, Myburgh KH. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clin J Sport Med. 2009;19(5):399-404.

2. US Food and Drug Administration. The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication. Issued 28 November 2017, updated 5 November 2019.

3. National Environment Agency, Singapore. Climate of Singapore, and daily UV Index readings.