How Much Hair Loss Is Normal? What the Research Actually Counted

Why this page exists

"How much hair loss is normal?" is one of the most-searched hair questions, and almost every answer repeats the same line: 50 to 100 hairs a day. The American Academy of Dermatology uses that range too. Read the AAD page →

We wanted to know where the number came from, what was actually measured, and on whom. The answer is more useful — especially if you are looking at your drain right now — than the number itself.

The "100 a day" figure was calculated, not counted

In 2008, a hospital-based dermatology team set out to standardise a simple test: combing for 60 seconds and counting what comes out. Explaining why the test was needed, they set out the usual arithmetic behind "100 a day": roughly 100,000 scalp hairs, about 10% of them in the resting (telogen) phase, and a resting phase of about 100 days. Divide, and you get about 100 hairs released a day.

They then pointed out that no clinical study or standardised method had validated that number. Read the study →

Every input in the sum varies between people — how many hairs you have, what share are resting, how long they rest. So the result is a rough order of magnitude, not a line you cross.

When people did count, "normal" depended on the method

60-second count, 2008 → · Refined wash test, 2022 → · Seasonal study, 1991 → · Pull test, 2017 →

Four methods, four different "normals". Even within one method, counts move around: when an Italian group repeated their wash test weekly for four weeks, the total hair count in people without hair loss was only moderately consistent. Read the reliability study →

Notice, too, who most of this data comes from: small groups of white men with straight hair, one city in northern England, adults in one country. The 2008 authors flagged that their results may not apply to other ethnicities, and they excluded people with curly or long hair.

Every one of these tests also fixes how long it has been since the last wash — one widely cited version asks for five days without shampoo, the 2022 version just one. Hair that has already let go collects until you wash or brush it out, so a pile after three unwashed days cannot be compared with a pile after one.

If you are going to count, compare yourself with yourself: same number of days since washing, same brush or drain, same routine. A number from the internet was produced under different conditions.

The hairs tell you more than the count

The 2022 wash-test study measured the hairs as well as counting them.

• People with telogen effluvium — the stress- or illness-triggered shedding — shed the most hairs by far, but those hairs were full thickness, about 83 micrometres on average.
• People with pattern hair loss shed fewer than that, but their shed hairs were thinner, about 60 micrometres, and around 8% were fine vellus hairs, compared with about 1% in the other two groups.
• Combining the count with the share of fine hairs separated pattern hair loss from normal shedding far better than the count alone.

Read the study →

The older Italian modified wash test is built on the same idea: it looks at the proportion of short, fine hairs as well as the total. Read about the method →

The uncomfortable implication: pattern hair loss can be quieter in the drain than stress shedding. A small pile of finer hairs may say more than a dramatic pile of normal ones.

These were specialist measurements, taken with magnifying equipment and averaged across groups. They were not designed as a home test, and they should not be used as one.

A resting hair does not simply fall out

The textbook hair cycle is usually drawn as grow (anagen), transition (catagen), rest (telogen), fall. Hair researchers have spent two decades arguing that the last step is its own event.

• In 2001, two Belgian dermatologists proposed teloptosis as the name for the moment a resting hair actually lets go — a loss of adhesion between the club-shaped root and the cells around it. They noted it is triggered separately from the start of the next growth phase. Read the paper →
• In 2002, a mouse study described exogen: shedding as an active, separately controlled phase rather than a passive end to resting. Read the study → A 2009 review examined how that applies to human hair. Read the review →
• Also in 2002, Italian researchers described kenogen: the time a follicle sits empty after its hair has gone. In 10 men followed for 14 years it lasted about four months, sometimes up to about seven. In two women with progressing pattern hair loss, it affected more follicles and could last up to a year. Read the paper →

This is not settled. A 2017 study of the roots of shed hairs from 25 women found exogen-type roots made up only 2.6% of hairs in women without hair loss, with no significant difference in pattern hair loss or telogen effluvium. Read the study →

What it means for you: the hair in the shower is the end of a process that began earlier, and an empty follicle can be a normal pause rather than a dead one. In pattern hair loss, the kenogen work suggests, those pauses tend to be longer and more common.

Today's shedding usually started earlier

Telogen effluvium was described by the dermatologist Albert Kligman in 1961. Read the paper → In the common acute form, a shock pushes a large group of growing hairs into rest at the same time, and they are released together — often two to three months later. Read the review → After childbirth, the AAD describes shedding becoming noticeable at around two months and peaking at around four. Read the AAD page →

There is more than one way the cycle can be knocked off course. A 1993 review set out five, including a growth phase ending early and a resting phase ending early read the review →; a 2016 proposal simplified them to three. Read the proposal →

COVID-19 became an accidental test of the timing. In 30 patients seen in the US, Brazil and Spain, shedding began a median of 45 days after a positive test and lasted a median of about seven weeks (12 to 100 days). Read the letter → A Brazilian group described some hospitalised patients shedding within 30 days, with signs of damage to growing hairs rather than a simple shift into rest. Read the letter → "Two to three months" is a tendency, not a clock.

When shedding spikes, look back as well as around. The AAD's list of common triggers includes childbirth, a high fever or illness, surgery, major stress, losing 20 pounds or more, and stopping birth-control pills.

Starting a hair-loss medicine can also be followed by a temporary increase: a 2026 review of low-dose oral minoxidil reported transient shedding in 16–22% of patients. Read the review → If you are on a prescribed treatment, talk to your prescriber before changing it because of shedding.

Late summer is measurably different

Three separate data sets, collected decades apart, found the same seasonal shape:

• Sheffield, 1991: in 14 men, the share of growing follicles peaked at over 90% in March and fell to its lowest in September; shedding peaked in August and September. Read the study →
• France, 1996: in a study from L'Oréal's research laboratories, 10 men photographed at the same spot on the crown for 8 to 14 years showed the highest share of resting hairs at the end of summer and start of autumn. Some had two peaks a year; those with very few resting hairs showed no rhythm at all. The authors noted the rhythm is not independent of climate, such as hours of sunshine. Read the study →
• Switzerland, 2009: trichograms from 823 apparently healthy women seen at the University Hospital of Zürich's dermatology department with a complaint of hair loss (after excluding anyone with a disease or on a medicine known to cause it) showed the most resting hairs in summer, a smaller peak in spring, and the fewest in late winter. Read the study →

The limits matter: all three are European, and mostly measured the share of resting hairs in a clinic rather than daily counts at home. There is no data here for the southern hemisphere or the tropics.

Still, a heavier September than February is not, on its own, evidence that something is wrong. Comparing this September with last September is fairer.

"Chronic telogen effluvium" is less settled than it sounds

Shedding that lasts more than six months is usually labelled chronic telogen effluvium. Read the review → In 2023, a group of hair researchers in the UK, US and Australia asked whether it is really a distinct condition.

They found 18 studies covering 1,628 cases, 97.5% of them women. No study documented that it had ruled out every other cause of shedding. Only eight cases were followed forward in time. No study objectively examined the effect of hair length, or of distress and preoccupation with shedding. The authors concluded that many cases are probably early female pattern hair loss or shedding with a cause nobody found — and that some may be preoccupation with normal shedding in anxious people with long hair. Read the review →

For balance: a 2014 biopsy study of 20 women with chronic telogen effluvium, 17 with mild pattern hair loss and 9 controls concluded the two are separate conditions. Read the study →

If you have been told "it's just chronic telogen effluvium", it is reasonable to ask what was ruled out, and whether early pattern hair loss has been considered.

When shedding deserves a proper look

See a dermatologist or your doctor if:

• there are patches, smooth round areas, a widening part or a receding hairline alongside the shedding;
• your scalp is painful, burning, red, scaly or has spots;
• hairs are breaking off, or you are losing eyebrow, eyelash or body hair;
• heavy shedding has continued for more than about six months;
• there is no trigger you can identify, or it comes with other symptoms such as tiredness or unexplained weight change.

An appointment may include questions going back several months, a gentle pull test, a close look at the scalp with a dermatoscope, and sometimes blood tests, a wash test or — for long-lasting shedding — a biopsy. Read the EEMCO guidance →

It helps to bring dates (illness, childbirth, surgery, diet changes, new or stopped medicines), photographs taken at the same angle a month apart, and — if you have been counting — exactly how you counted.

Where laser caps fit, and where they don't

We sell a laser cap, so read this with that in mind.

The clinical evidence for low-level laser therapy is in androgenetic, or pattern, hair loss. Telogen effluvium usually settles once its trigger has passed — after childbirth, the AAD describes hair regaining its normal fullness within six to nine months — and a laser cap is not the answer to it.

The two can overlap: in the COVID-19 group above, 26.7% of patients also had pattern hair loss, and the Italian wash-test studies describe people with both. If a clinician tells you there is pattern hair loss underneath the shedding, that is when a device like ours becomes a reasonable thing to discuss. Pattern hair loss explained →

What to expect from a laser cap → · Menopause and postpartum hair changes → · Why doctors are sceptical of laser caps →

Not intended to diagnose, treat, cure, or prevent any disease. The clinical studies referenced evaluated a clinically studied 650nm wavelength and the low-level laser therapy category broadly. Individual results vary and depend on consistent use over time. The FDA 510(k) clearance (K261253) is held by the manufacturer.