Telogen Effluvium or Pattern Hair Loss? How to Tell Which One You Have

By Dr. Susan Lin, MD | MD HAIR | La Cañada Ventures, Inc.
Published on mdhair.com — Hormonal & Life Stage Hair Loss Series

You have been counting. Not deliberately at first — you just noticed the drain, and then the pillow, and then the strands on the back of your black coat, and at some point noticing turned into counting. Now you have a number in your head and no idea what to do with it.

And you have been searching, which is how you arrived here, and the searching has told you two contradictory things. One set of pages says this is temporary, it happens after stress or illness or a baby, it will stop in six months, don't panic. Another set says this is genetic, it is progressive, and every month you wait is density you will not get back. Both descriptions sound like you. Neither of them tells you which one you are.

I want to give you the framework a physician actually uses in the room, because the distinction is not mystical and it is not usually difficult. It rests on a small number of questions about pattern, timing and the hair itself, and you can answer most of them at home before you ever see anyone. Then I want to tell you the part that most articles leave out, which is that the two conditions coexist far more often than the tidy either/or framing suggests — and that this is the single most common reason people misread what is happening to their own head.

Two Conditions That Feel Identical in the Shower

Here is the core of it, stated plainly before the detail.

Telogen effluvium is a timing problem. Something happened to your body, and in response an abnormally large share of your follicles left the growing phase early and entered rest together. Months later they release together. The follicles themselves are healthy. The hair that falls is full-calibre hair. The loss is diffuse — spread across the whole scalp, including the back and sides, which pattern loss generally spares.

Androgenetic alopecia — pattern hair loss — is a size problem. Individual follicles, under the influence of androgens they are genetically sensitive to, produce a slightly finer, slightly shorter hair with each cycle. The follicle does not die. It shrinks. Over years, terminal hairs are replaced by hairs so fine and short they no longer contribute to visible coverage. The loss is patterned — concentrated at the part, the crown, the frontal zone — because those follicles carry the androgen sensitivity and the occipital scalp largely does not (Sawaya & Price, 1997).

One is a wave. The other is erosion. A wave is loud and frightening and mostly resolves. Erosion is quiet, and it is the one that takes ground permanently if nothing interrupts it.

Telogen Effluvium: The Trigger and the Three-Month Lag

The defining feature of a telogen effluvium is not the shedding. It is the gap between cause and effect.

A normal scalp holds most of its follicles in anagen — active growth — for somewhere between two and six years, with roughly 5–15% resting in telogen at any moment, each cycling independently so that shedding is a quiet background of about 50–100 hairs a day. A systemic insult can push a large, abnormal fraction of anagen follicles into telogen at once. But telogen is a resting phase that lasts roughly two to three months before the club hair is released. So the follicles that quit in March do not shed in March. They shed in June (Grover & Khurana, 2013; Malkud, 2015).

This lag is why patients so often tell me nothing happened, and then, when I ask about the preceding spring rather than the preceding week, produce a list.

The triggers that reliably do this:

• Childbirth — the most common cause in women of reproductive age
• A high fever, a significant infection, hospitalization or surgery
• Rapid or substantial weight loss, restrictive dieting, bariatric surgery
• Iron deficiency, with or without anaemia — low ferritin is the most commonly missed contributor in women (Trost et al., 2006)
• Thyroid dysfunction in either direction
• Starting or stopping a medication, including hormonal contraception
• Severe or sustained psychological stress
• Major hormonal transitions, including the perimenopausal years

What it looks like: diffuse thinning over the entire scalp. Reduced ponytail circumference. Hair coming out during washing and brushing in handfuls rather than strands. Often the scalp feels tender or the hair feels loose. Crucially, the part line and crown do not look disproportionately worse than the back and sides — everything thins together.

What it does: an acute telogen effluvium characteristically peaks and then settles, with shedding subsiding within three to six months of the trigger being removed and cosmetic recovery over the following six to twelve. Because the follicles are structurally intact, recovery is the expected outcome (Rebora, 2019). A chronic telogen effluvium — shedding that persists beyond six months, often fluctuating for years — is a different and more frustrating entity, and it deserves a physician's assessment rather than patience.

Pattern Hair Loss: Miniaturization You Can Almost Watch

Androgenetic alopecia announces itself differently, and much more slowly.

Testosterone is converted at the follicle by the enzyme 5-alpha-reductase into dihydrotestosterone (DHT). In genetically susceptible follicles, DHT binding shortens the anagen phase with each successive cycle. Shorter anagen means a shorter hair. It also means a smaller follicle producing a narrower shaft. Repeat across ten or fifteen cycles and a terminal hair becomes a vellus-like hair — the fine, short, nearly colourless kind you have on your forearm (Whiting, 1993).

Two consequences follow, and both are diagnostic.

First, the calibre becomes uneven. A healthy scalp has hairs of broadly similar thickness. A scalp with pattern loss has a visible mix — thick hairs next to thin ones next to barely-there ones, in the same square centimetre. Dermatologists call this anisotrichosis, and on dermoscopy it is one of the most reliable signs there is (Rudnicka et al., 2008).

Second, it is regional. In women the usual distribution is the Ludwig pattern: progressive central thinning with preservation of the frontal hairline, graded I to III by severity (Ludwig, 1977). The part widens. The crown thins when you look down at it in a mirror. The temples and occiput look comparatively normal. In men the recession is frontotemporal and vertex-centred. Olsen additionally described a frontal accentuation — the "Christmas tree" pattern — in which the widening is greatest at the front of the part (Olsen, 2001).

And the shedding is often unremarkable. This is the part that confuses people most. Pattern loss can progress substantially with a completely normal daily shed count, because the hairs being lost are being replaced — just by smaller ones. You do not notice a wave. You notice, one afternoon in unfamiliar bathroom lighting, that your scalp is showing.

Six Questions That Usually Settle It

If you answered in the left column throughout, you are most likely looking at a shed. If you answered in the right column throughout, you are most likely looking at pattern loss. If you answered in both — which is extremely common — read the coexistence section below, because that is probably the real answer.

The Pull Test: What It Is and What It Actually Tells You

The pull test is the single most useful bedside manoeuvre in this whole assessment, and it is routinely done wrong at home.

How it is performed properly. Hair should not have been washed for about 24 hours — washing removes the loose telogen hairs you are trying to detect and produces a falsely reassuring result. Grasp roughly 50–60 hairs close to the scalp between thumb, index and middle finger, and draw firmly and steadily along the shaft to the tip. Do not yank. Count what comes away. Repeat in several zones: frontal, both parietal, vertex, occipital (Dhurat & Saraogi, 2009).

How to read it. Fewer than about three hairs per pull is generally considered normal. Six or more is a positive test, indicating active shedding. What matters at least as much as the number is where it is positive. A pull test positive everywhere, including the occiput, is the signature of an active telogen effluvium. A pull test positive only over the crown and part, with a negative occiput, points toward active pattern loss.

Its limits, honestly. It is operator-dependent, it is affected by when you last washed and how much you brush, and a negative test does not exclude anything — pattern loss frequently produces a negative pull test even while it is quietly progressing. It tells you about activity right now. It does not tell you about the diagnosis on its own.

Look At the Hair Itself

Take a few of the fallen hairs to a window and look at the root end. This costs nothing and is genuinely informative.

• A telogen (club) hair has a small, rounded, pale, keratinised bulb — like a tiny white matchhead. It has completed its cycle and been released. Fallen hairs in a telogen effluvium are almost all club hairs, and almost all full length and full thickness.
• An anagen hair pulled out prematurely has a soft, pigmented, sometimes distorted root, occasionally with a gelatinous sheath. Large numbers of these are not a normal shed and warrant prompt medical assessment.
• No bulb at all, with a frayed or blunt end, means the hair did not shed — it broke. Breakage is a different problem entirely, with different causes and different solutions.
• Very short, very fine hairs with a normal small bulb, mixed among normal ones, are miniaturized hairs, and they belong to the pattern-loss story.

The Part Everyone Gets Wrong: They Coexist

Here is what I want you to take from this article more than anything else.

Telogen effluvium and androgenetic alopecia are not mutually exclusive, and in adult women they very often occur together. They have overlapping triggers — perimenopause, postpartum hormonal collapse, thyroid disease, iron deficiency — and one of them actively reveals the other.

The mechanism of that revelation is worth understanding. Pattern loss progresses invisibly for years because the miniaturized hairs are still there, thin and short, but present, and they are hidden underneath the terminal hairs around them. When a telogen effluvium strips out a large fraction of the terminal hairs all at once, the miniaturized ones are suddenly exposed. The part line, which had been quietly widening for five years without you registering it, becomes obvious in a fortnight.

Then the shed resolves. The terminal hairs regrow. But density does not return to where you remember it — because it was never where you remembered it. The shed did not cause the pattern loss; it removed the camouflage.

This is why the two most common misreadings both happen at once:

• Women with new-onset pattern loss are reassured that it is just a shed and will grow back, and wait two years before anyone addresses the androgenetic component — which is the one with a time cost.
• Women with a straightforward postpartum or post-illness shed are told they have genetic hair loss, and start treating a self-limiting condition as a permanent one.

The clinically useful posture is not to pick a side. It is to ask: is there an acute shed here, is there an underlying pattern here, and what does each one need?

What Each One Needs

A telogen effluvium needs its cause found and removed. That means labs, not products: a full thyroid panel, serum ferritin — not just haemoglobin, since the follicle feels iron shortage long before red cell production does — vitamin D, and a genuine review of medications, weight change and recent illness. Correct what is correctable, protect nutrition and sleep, and then let the cycle do its work. No topical accelerates a shed's resolution faster than removing the trigger does.

Pattern loss needs a decision about time. It is progressive by definition. The follicle remains responsive for as long as it remains a follicle — miniaturization is not the same as fibrosis, and a miniaturized follicle can enlarge again if its environment changes. But a follicle that has been replaced by fibrous tissue cannot. That asymmetry is the entire argument for acting earlier rather than waiting to see. Whatever you choose — pharmaceutical, drug-free, or a combination — the intervention that works best is the one that started sooner.

And both need patience measured in the units the follicle uses. Anagen runs for years; a full cycle cannot report back in weeks. Ninety days is the minimum honest window in which to assess anything in this category, including everything I make. Photograph your part in the same room, in the same light, at the same time of day, on the first of every month. Memory is a poor instrument for something that changes by one percent a month; photographs are not.

The Bottom Line

Telogen effluvium is diffuse, abrupt, follows an identifiable trigger by about three months, sheds full-thickness hair from the whole scalp including the back, and resolves when its cause is addressed. Pattern hair loss is regional, gradual, concentrated at the part and crown with the back and sides spared, produces hairs of visibly mixed calibre, and progresses unless something interrupts it.

Look at where it is thinner, when it started, what happened three months before, and whether the hairs are all the same thickness. Those four observations resolve most cases. Do the pull test properly — unwashed for a day, several zones, and pay attention to whether the occiput is positive.

And hold both possibilities at once. The most common real-world scenario in the women I see is not one or the other. It is a shed that pulled back the curtain on a pattern that had been advancing quietly underneath it for years — which means the shed is the thing that will resolve on its own, and the pattern is the thing that will not.

Dr. Susan Lin's Clinical Perspective

"The mistake I see most often is not misdiagnosis — it is premature certainty. A woman is told 'it's just stress' at the exact moment her part line begins to widen, and two years of progression get filed under reassurance. The discipline I would ask for instead is simple sequencing: establish whether there is an acute shed, establish whether there is an underlying pattern, and treat both as separate questions with separate answers. The shed needs its trigger found and its labs drawn — ferritin, thyroid, vitamin D — because no topical outperforms removing the cause. The pattern needs a decision made about time, because a miniaturized follicle is recoverable and a fibrosed one is not, and the interval between those two states is the only part of this that is genuinely urgent."

— Dr. Susan F. Lin, M.D., Physician Formulator, MD HAIR

Mechanism Spotlight: Why a Trigger in March Shows Up in June

The three-month lag is not a quirk of observation. It is arithmetic built into the hair cycle.

Every follicle runs a three-phase programme: anagen, active growth lasting two to six years on the scalp; catagen, a brief regression of two to three weeks in which the lower follicle involutes; and telogen, a rest of roughly two to three months during which the follicle holds a fully formed club hair — keratinised, detached from its blood supply, mechanically anchored but biologically finished. Release of that club hair, sometimes described as a distinct exogen step, occurs at the end of telogen as the new anagen hair grows up beneath it (Grover & Khurana, 2013).

A systemic insult — fever, surgery, delivery, abrupt caloric restriction, an iron-depleted marrow — acts on follicles in anagen, pushing an abnormally large cohort into catagen and then telogen simultaneously. Nothing visible happens at that moment. The hairs are still attached. What has changed is that thousands of follicles that should have been staggered across the cycle are now marching in step.

Two to three months later that cohort reaches the end of telogen together and releases together. The shed you experience in June is a delayed, synchronized readout of an event in March (Malkud, 2015).

Two consequences follow. First, the trigger is always in the past by the time you notice, which is why patients so consistently report that nothing happened — they are looking at the wrong month. Second, because the follicles are structurally intact and merely resynchronized, the same arithmetic predicts recovery: they re-enter anagen on their own schedule and, over the following six to twelve months, drift back out of synchrony. The wave is self-limiting because the mechanism that produced it was timing, not damage.

Recommended Reading

Pillar pages on mdhair.com:

• Hormonal Hair Loss: Every Stage, Every Cause
• Drug-Free Hair Loss Treatment — The Complete Guide
• The Scalp Health Guide
• The Clinical Evidence Behind MD HAIR

Related articles in this series:

• Postpartum Hair Loss: Why Your Hair Is Falling Out After Baby — the textbook example of a synchronized shed unmasking a pattern underneath it
• Why Your Hair Is Falling Out in Your 40s: Perimenopause, Estrogen Decline — the life stage in which both processes most often run at the same time
• Weight Loss and Hair Loss — one of the most reliable triggers of a synchronized shed, explained
• Stress and Hair Loss: The Connection, and What to Do About It — how sustained stress feeds a diffuse shed

Our sister site md-factor.com carries the same MD® formulation and documentation standards across the wider portfolio, including the ingredient specifications referenced here.

Not sure which of the two you are dealing with? Take the MD HAIR Quiz — it is a structured way to organize the observations above, not a diagnosis.

MD HAIR Product Recommendation

MD® Hair Restoration Kit — /products/hair-restoration-kit

The reason I recommend the kit rather than a single bottle for this particular reader is that this article's honest conclusion is usually both — an acute shed sitting on top of a slowly progressing pattern — and those two situations ask for different things at the same time. The Restoration Kit is the two-step topical system used together as a system: cleansing and leave-on care in the sequence they were designed to be used in, applied to the scalp rather than to the hair, at the part, crown and hairline where pattern change shows first. It is drug-free and hormone-free, so it layers with whatever your own physician has you on for the shed's underlying cause and does not complicate a thyroid or iron workup. In a 119-day (17-week) Spincontrol North America study of the two-step topical system — n=24, split-scalp design, self-reported questionnaire, no placebo arm — 71% agreed their hair growth had improved. The report's own assessment states that "the satisfaction rate (concerning the overall efficacy) is not significantly validated." Individual results vary; study on file. Physician-formulated by Dr. Susan F. Lin, M.D. under the MD® mark (U.S. Reg. No. 4,471,494) and manufactured in FDA-registered, GMP-compliant facilities in the USA. These are cosmetic products and are not intended to diagnose, treat, cure, or prevent any disease.

Alongside it: MD Nutri Hair™ — /products/nutri-hair-supplement

Because both conditions in this article involve the scalp's inflammatory and hormonal environment, I pair the topical with an internal input rather than asking you to choose between them. The best-evidenced thing I can tell you about MD Nutri Hair™ concerns inflammation: its lilac component is standardized for verbascoside, a plant phenol which in controlled laboratory studies on human dermal papilla cells — the cells at the base of the follicle — reduced the release of pro-inflammatory signals including IL-1α, IL-6, IL-1β and TNF-α, induced cell proliferation, and prevented testosterone-induced cell death. Those are cell studies in a dish, not human trials; the authors state that clinical study is still needed, and the verbascoside studied was sourced from Acanthus, not from lilac — the same molecule from a different botanical source, and not a study of our own material (Wisuitiprot et al., 2022). Read more at the lilac & verbascoside science page. The capsule is a once-daily 300 mg proprietary blend with vitamin B3 as niacinamide, vitamin E as alpha tocopheryl acetate, and D-biotin at 0.05 mg — a sensible cofactor dose rather than the megadoses that can interfere with laboratory immunoassays, which matters if you are about to have thyroid or ferritin testing done. Other ingredients: flaxseed powder, lignan powder, lilac. In the MD Nutri Hair™ 30-day in-office consumer use study (30 subjects, self-reported), 95% saw improved hair appearance, 90% reported better manageability, and 75% reported increased fullness. Individual results vary. As a dietary supplement it is not intended to diagnose, treat, cure, or prevent any disease, and it is not FDA approved — no dietary supplement is. Label warning: keep out of the reach of children. Do not take if you are pregnant or breast feeding. For adults only; one capsule daily.

A note on the assessment window: ninety days is the minimum honest period in which to judge anything in this category, mine included. A follicle cannot report back faster than it grows.

A note on authenticity: genuine MD HAIR™ and MD Nutri Hair™ products are sold only through mdhair.com, md-factor.com, and the official La Cañada Ventures, Inc. stores on Amazon and Walmart. We cannot verify the storage, handling, labelling or lot integrity of units bought anywhere else.

Learn more about hormonal hair loss at mdhair.com/pages/hormonal-hair-loss

References

1. Grover C, Khurana A. (2013). Telogen effluvium. Indian Journal of Dermatology, Venereology and Leprology, 79(5), 591–603. PMID 23974577
2. Malkud S. (2015). Telogen effluvium: a review. Journal of Clinical and Diagnostic Research, 9(9), WE01–WE03. PMID 26500992
3. Rebora A. (2019). Telogen effluvium: a comprehensive review. Clinical, Cosmetic and Investigational Dermatology, 12, 583–590. PMID 31686886
4. Ludwig E. (1977). Classification of the types of androgenetic alopecia (common baldness) occurring in the female sex. British Journal of Dermatology, 97(3), 247–254. PMID 921894
5. Olsen EA. (2001). Female pattern hair loss. Journal of the American Academy of Dermatology, 45(3 Suppl), S70–S80. PMID 11511856
6. Whiting DA. (1993). Diagnostic and predictive value of horizontal sections of scalp biopsy specimens in male pattern androgenetic alopecia. Journal of the American Academy of Dermatology, 28(5 Pt 1), 755–763. PMID 8496421
7. Sawaya ME, Price VH. (1997). Different levels of 5α-reductase type I and II, aromatase, and androgen receptor in hair follicles of women and men with androgenetic alopecia. Journal of Investigative Dermatology, 109(3), 296–300. PMID 9284093
8. Dhurat R, Saraogi P. (2009). Hair evaluation methods: merits and demerits. International Journal of Trichology, 1(2), 108–119. PMID 20927232
9. Rudnicka L, Olszewska M, Rakowska A, Kowalska-Oledzka E, Slowinska M. (2008). Trichoscopy: a new method for diagnosing hair loss. Journal of Drugs in Dermatology, 7(7), 651–654. PMID 18664157
10. Trost LB, Bergfeld WF, Calogeras E. (2006). The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. Journal of the American Academy of Dermatology, 54(5), 824–844. PMID 16635664
11. Wisuitiprot V, Ingkaninan K, Chakkavittumrong P, Wisuitiprot W, Neungchamnong N, Chantakul R, Waranuch N. (2022). Effects of Acanthus ebracteatus Vahl. extract and verbascoside on human dermal papilla and murine macrophage. Scientific Reports, 12(1), 1491. PMID 35087085

Dr. Susan F. Lin, M.D. is the physician formulator behind MD HAIR and MD Nutri Hair™, product lines of La Cañada Ventures, Inc. — physician-formulated since 2008 under the MD® mark (U.S. Reg. No. 4,471,494). She trained at Boston University School of Medicine and is board-certified in Obstetrics & Gynecology and in Anti-Aging Medicine (A4M).

MD® products are cosmetics and dietary supplements manufactured in FDA-registered, GMP-compliant facilities. "FDA-registered" describes the facility, not the product: MD® products are not FDA approved, and no cosmetic or dietary supplement is. Individual results vary. MD Nutri Hair™ is a dietary supplement. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Because there are no clinical data in pregnant or breastfeeding women, we do not advocate using MD HAIR products during pregnancy or lactation.

This article is for educational purposes and does not constitute medical advice. Diffuse or patterned hair loss can reflect thyroid disease, iron deficiency, medication effects or other medical conditions; consult your own physician for evaluation, and do not start, stop, or change any medication without consulting your prescriber.

Explore more in our Hormonal & Life Stage Hair Loss series at mdhair.com/pages/hormonal-hair-loss