Telogen effluvium
Telogen effluvium (TE) is the most mechanistically transparent form of hair loss. The pathway from trigger to shedding is well-characterised, the follicles are not damaged, and the process is self-limiting once the underlying cause resolves. What makes it clinically challenging is not the biology but the presentation: the shedding becomes visible two to four months after the trigger, by which point clients have often lost sight of the cause; it overlaps with androgenetic alopecia in a substantial proportion of cases; and chronic telogen effluvium (lasting more than six months) follows a different, more complex course than the acute form. Understanding these distinctions precisely changes both the client conversation and the treatment logic.
Telogen effluvium (TE) is a diffuse, non-scarring hair loss condition that results from the premature or synchronised shift of a significant number of scalp hair follicles into the telogen (resting) phase. [1] Under normal conditions, approximately 85–90% of scalp follicles are in anagen at any given time, with only 10–15% in telogen; a distribution maintained by the independent, asynchronous cycling of individual follicles. When a systemic stressor synchronises a large proportion of follicles into telogen simultaneously, two to four months later those follicles reach the exogen phase together – the point at which the club hair detaches from its epithelial envelope and sheds – and diffuse shedding becomes visible.
The exogen phase deserves a brief clarification because it is often described as simply “late telogen,” but it is a distinct regulated event. Teloptosis – the termination of telogen with actual hair shedding – is triggered by loss of adhesion between the cells of the club hair and its epithelial envelope, and is independently regulated from the initiation of the next anagen phase. karger.com A telogen hair remains in its follicle for up to four to six weeks after the next anagen phase has already begun, which is why the visible shedding event lags behind both the original trigger and the follicle’s actual return toward growth.
Five Mechanisms: Not One Type of Telogen Effluvium
A common oversimplification is treating telogen effluvium as a single mechanism: stress pushes follicles into telogen, they shed two to four months later. In reality, five distinct mechanisms can produce the TE pattern, each with different trigger types and different anagen:telogen cycle kinetics:
- Immediate anagen release: the most common mechanism, in which an acute stressor prematurely terminates anagen and forces follicles into telogen; shedding appears two to four months later. This is the mechanism operative in rapid weight loss, post-surgical stress, and acute illness.
- Delayed anagen release: prolongation of anagen followed by synchronised, delayed telogen entry. The most common example is postpartum TE, where pregnancy hormones extend anagen, and the removal of that hormonal support at delivery synchronises large numbers of follicles into telogen simultaneously.
- Short anagen syndrome: idiopathic shortening of the anagen phase leading to more rapid overall cycling and persistent TE. This is believed to underlie most cases of chronic telogen effluvium.
- Immediate telogen release: shortening of the telogen phase producing a massive, rapid release of club hairs. Less common, but implicated in some drug-induced TE.
- Delayed telogen release: prolongation of telogen followed by synchronised release. Can occur seasonally, explaining the phenomenon of increased autumnal shedding in some individuals.
The 5 Kinetic Mechanisms of TE
| Mechanism | Trigger Example | Timing of Shedding |
|---|---|---|
| Immediate Anagen Release | High fever, GLP-1 weight loss. | 2–4 months post-trigger. |
| Delayed Anagen Release | Postpartum (Oestrogen drop). | 3–6 months post-delivery. |
| Short Anagen Syndrome | Chronic TE (CTE). | Persistent, fluctuating. |
| Immediate Telogen Release | Drug-induced (e.g., Minoxidil start). | Rapid (weeks). |
| Delayed Telogen Release | Seasonal (Autumnal) shedding. | Predictable, annual. |
Acute vs Chronic Telogen Effluvium
Acute and chronic telogen effluvium are distinct in their timeline, scalp biopsy findings, and clinical course. Conflating them leads to both inaccurate prognosis and inappropriate management.
Acute TE is defined as shedding lasting less than six months. On scalp biopsy, the anagen:telogen ratio is normal or even supernormal – follicles are present and cycling, the hair population is intact – and follicular miniaturisation is absent. [1] This is mechanistically consistent with the immediate anagen release pathway: the stressor caused synchronised telogen entry, the follicles are now returning to anagen, and biopsy captures a population that is recovering. Acute TE resolves once the triggering factor is removed, and hair density returns to baseline.
Chronic TE is defined as shedding lasting more than six months. Biopsy shows an anagen:telogen ratio of 8:1 (substantially lower than the normal 14:1) reflecting persistently elevated telogen counts. [1] Chronic TE primarily affects middle-aged women, presents as a prolonged fluctuating course without follicular miniaturisation or widening of the central part, and is thought to represent short anagen syndrome rather than ongoing acute stress. Treatment is more complex than simply removing a trigger – the trigger is often the shortened anagen phase itself, and management requires addressing multiple potentially compounding factors including thyroid function, iron and ferritin levels, and nutritional status.
The AGA Overlap: More Common Than Expected
One of the most clinically significant findings in the TE literature is the frequency with which it co-presents with androgenetic alopecia. In a study of 100 patients presenting with hair loss concerns, 39% had both AGA and CTE simultaneously, making the combined presentation the most common single diagnosis, more frequent than either condition alone. jamanetwork.com A further 24% had AGA alone, and 32% had CTE alone.
The clinical challenge is that the two conditions compound each other: AGA produces progressive follicle miniaturisation that reduces hair density from below; TE produces acute diffuse shedding that reduces the apparent density of the remaining terminal hair population from above. A client experiencing significant shedding on a background of pre-existing AGA will present with a more alarming degree of visible thinning than the TE alone would produce, and the TE shedding may accelerate the visible progression of AGA by depleting the terminal hair density faster than it would naturally miniaturise.
Distinguishing CTE from AGA in clinical assessment uses the vellus hair proportion in shed hairs: AGA produces shedding of significant numbers of short telogen vellus hairs (≤3 cm), reflecting the miniaturised follicle population; CTE produces shedding predominantly of longer terminal telogen hairs. jamanetwork.com CTE patients shed approximately 250 hairs in standardised wash tests; AGA patients approximately 70. jamanetwork.com
Differential Diagnosis (TE vs. AGA)
| Clinical Feature | Telogen Effluvium (TE) | Androgenetic Alopecia (AGA) |
|---|---|---|
| Pattern | Diffuse (entire scalp). | Localised (crown/temples). |
| Hair Diameter | Consistent (terminal hairs). | Varied (miniaturised/vellus). |
| Daily Shedding | High (>100–300+ hairs). | Normal to slightly elevated. |
| Shed Hair Length | Mostly long (>3cm). | Mixed (includes many <3cm). |
| Follicle Status | Healthy but “resting.” | Progressive miniaturisation. |
The Molecular Mechanism: GAS6, Cortisol, and the DPC Connection
The molecular pathway through which stress triggers telogen effluvium – established in detail in the Corticosterone and GAS6 entities – operates specifically through dermal papilla cells rather than directly on hair follicle stem cells. Chronic glucocorticoid elevation suppresses GAS6 secretion from DPCs; without GAS6, HFSCs cannot receive the activation signal required to initiate anagen; follicles remain in extended telogen. nature.com This is the pathway operative in psychological stress, sleep deprivation, and the rapid caloric restriction of GLP-1-driven weight loss – all of which activate the HPA axis and elevate cortisol in humans.
In androgenetic alopecia, a parallel DPC suppression pathway operates: DHT drives DPCs to downregulate Wnt/β-catenin and FGF-7 output and upregulate TGF-β2, progressively shortening anagen. [4] When AGA and stress-driven TE coexist, both pathways are suppressing DPC signalling simultaneously, compounding the follicle cycling disruption through two independent mechanisms.
Clinical Application
Telogen effluvium is one of the most common hair concerns presenting at Creative Touch, both as a standalone concern and as the hair loss component of the broader GLP-1 weight loss picture. The client conversation around TE is as important as the treatment decision, and the mechanistic precision available now allows both to be considerably more specific than the general reassurance that typically accompanies a TE diagnosis.
The client conversation: mechanism, timeline, and prognosis
The most useful thing to establish early with any client presenting with significant hair shedding is the likely trigger and its timeline. Shedding that began two to four months ago points to a trigger two to four months before that. For GLP-1 weight loss clients that means the shedding they are experiencing now reflects the metabolic stress of the rapid weight loss phase they went through earlier, not the current state of their medication or their health. [1] That reframe alone – the trigger is in the past, not the present – is genuinely reassuring in a way that general “this is temporary” framing is not.
The second important framing is follicle integrity. In acute TE, the follicles are not damaged. The stem cell population in the bulge is intact, GAS6-mediated reactivation will occur once glucocorticoid suppression eases, and the hair that has shed will regrow from the same follicles that shed it. nature.com What clients are losing is hair shafts, not follicles, and the distinction matters enormously for prognosis.
The third, and most important, distinction to establish is whether AGA is present alongside TE. Given that 39% of hair loss patients have both simultaneously, jamanetwork.com assuming a presentation is purely TE without screening for AGA risks missing a progressive condition that requires different and additional management. For clients where diffuse shedding reveals a broader pattern of miniaturisation at the crown or temples, the AGA conversation needs to happen alongside the TE reassurance. Treatment planning needs to address both.
Treatment: when to treat and what to address
For acute TE where the trigger is identified and resolving, the primary intervention is removing or moderating the trigger where possible: slowing the rate of weight loss where clinically appropriate; addressing iron, ferritin, zinc, vitamin D, and protein adequacy; managing ongoing psychological stressors. [2] These are not supplementary suggestions, they address the specific nutritional depletion and HPA axis activation mechanisms that sustain GAS6 suppression and IGF-1 decline beyond the initial trigger event.
iPRF scalp treatment is most productive at a specific point in the TE recovery trajectory: once the triggering stressor is resolving and glucocorticoid levels are normalising, but before the recovering follicle population has had time to restore full anagen density. At this stage, DPCs are recovering their GAS6 and IGF-1 output, the HPA axis suppression is easing, and iPRF’s PDGF, IGF-1, and VEGF payload provides DPC activation through parallel receptor pathways – supporting the return to anagen from multiple angles simultaneously. [3] Treating during the acute suppressive phase (when glucocorticoid elevation is ongoing) is working against an active inhibitory signal; waiting until it has eased makes the treatment progressively more effective.
For cases where AGA coexists with TE, treatment planning addresses both layers: iPRF supports DPC function against both the glucocorticoid suppression and the DHT-driven IGF-1 deficit; and for clients appropriate for pharmacological support, the conversation about finasteride and minoxidil belongs alongside rather than instead of the regenerative treatment discussion.
For chronic TE – particularly in middle-aged women where short anagen syndrome is the likely underlying mechanism – the treatment picture is more complex. Multiple triggers often compound over time, and systematic investigation of thyroid function, iron studies, and nutritional status is the necessary first step before any topical or injectable treatment. iPRF in chronic TE is a supportive intervention rather than a curative one, most useful once compounding systemic factors have been identified and addressed.
References
Asghar F, Shamim N, Farooque U, et al. (2020). Telogen Effluvium: A Review of the Literature. Cureus, 12(5), e8320 . doi.org/10.7759/cureus.8320
Hughes EC, Syed HA, Saleh D (2026). Telogen Effluvium. StatPearls Publishing. ncbi.nlm.nih.gov/books/NBK430848
Natarelli N, Gahoonia N, Sivamani RK (2023). Integrative and Mechanistic Approach to the Hair Growth Cycle and Hair Loss. J Clin Med, 12(3) . doi.org/10.3390/jcm12030893
Zhang Y, Huang J, Fu D, et al. (2021). Transcriptome Analysis Reveals an Inhibitory Effect of Dihydrotestosterone-Treated 2D- and 3D-Cultured Dermal Papilla Cells on Hair Follicle Growth. Front Cell Dev Biol, 9, 724310 . doi.org/10.3389/fcell.2021.724310
Also Known As
- Temporary stress-induced hair loss
Clinical Associations
Referenced By
- this Associated biochemical entity Vascular endothelial growth factor Evidence: VEGF deficiency impairs perifollicular vasculature; reduced VEGF secretion from compromised DPCs contributes to telogen effluvium. PMC12153676.
- this Treated by Microneedling Evidence: Microneedling wound-healing cascade ( TGF-β, PDGF, VEGF) supports hair follicle anagen re-entry in telogen effluvium; documented in hair loss protocols. PMID 40056230, 2025.
- this Treated by Polynucleotides Evidence: PN anti-inflammatory and vascular effects address chronic inflammatory scalp environment contributing to prolonged telogen effluvium; documented in scalp treatment protocols. PMID 39951159.
- this Affected by Oestrogen decline Evidence: Hormonal upheaval of menopausal transition triggers telogen effluvium; declining oestrogen reduces anagen phase duration and protective follicular effects, increasing shedding. PMC10669803.
- this Dermal Papilla Evidence: In stress-driven shedding and weight-loss-induced telogen effluvium… the dermal papilla is the cell population whose function needs restoring
- this Hair follicle Evidence: Telogen effluvium shifts follicles into telogen; permanent portion retains regenerative capacity.
- this Hypothalamic–pituitary–adrenal axis Evidence: Cortisol from HPA inhibits hair growth; follicular peripheral HPA mediates stress-triggered telogen effluvium. PMC3381079
Learn More
This topic is discussed in 2 articles:
-
Temporary hair shedding where follicles synchronously enter resting phase due to metabolic stress
-
Struggling with thinning hair? Discover natural, effective treatments at Creative Touch. We offer iPRF therapy, PRP, and scalp micropigmentation in Rotherham, Sheffield and South Yorkshire.