Stress Hair Loss: Telogen Effluvium, Minoxidil, Biotin & Money

Table of contents

• Evidence summary
• What stress hair loss is
• Symptoms, diagnosis and red flags
• Causes and risk factors
• How stress affects hair: people vs mice
• What works and what does not
• Treatments: recovery, minoxidil and medicines
• Supplements and lifestyle claims
• Risks of common treatments
• Who to see
• Follow the money: who funds the research and who sells the treatments
• Related research
• Frequently asked questions
• Sources and funding notes

Evidence summary

Independent evidence and credibility scorecard

Independence tiers: 1 = regulator or government body; 2 = academic, professional or Cochrane team with no declared commercial funding for the work; 3 = independent authors with declared industry ties, a commercial interest in the treatment, or an advocacy mission; 4 = manufacturer-funded or manufacturer-authored. Credibility runs from A (highest) to D.

Most sources are from the US and UK, so the picture reflects English-speaking regulatory systems. The strongest point of agreement is between sources with opposite interests: dermatology bodies with no product to sell, and the label of minoxidil itself, both say that sudden shedding after a trigger is usually temporary and is not what over-the-counter minoxidil is sold for.

What stress hair loss is

"Stress hair loss" is not one diagnosis. People use the phrase for three quite different things, and they need different handling.

Telogen effluvium: the common one

Hair grows in cycles. At any time about 85% of scalp follicles are growing (anagen) and about 15% are resting (telogen). A resting hair stays for 2 to 4 months before a new hair pushes it out (BAD). After a shock to the body, many more follicles switch into the resting phase at once. DermNet, a New Zealand reference site, says as many as 70% of growing hairs can be pushed into telogen (DermNet). Those hairs then fall out together a few months later. That delayed, diffuse shed is telogen effluvium.

It is common, but its size is uncertain. A 2024 systematic review and modelling letter on telogen effluvium after COVID-19 (Jeon et al.) examines prevalence after the pandemic. Its dataset lists National Research Foundation of Korea funding. We could not confirm its prevalence figures, so we do not quote them.

Chronic telogen effluvium

Some people, mostly women, shed more than usual for longer than 6 months (BAD). A 2023 systematic review of 18 studies (1,628 cases, 97.5% female) questioned whether this is a separate condition. No study had excluded all possible causes. The abstract notes that no study had excluded all possible causes and that there is no consistent definition of the condition, so whether it is distinct remains open (Daunton et al. 2023). We did not see this review's funding statement.

Alopecia areata: an autoimmune disease often blamed on stress

Alopecia areata causes round, smooth bald patches, sometimes spreading to the whole scalp or body. It is an immune condition, not a shedding pattern. Diffuse alopecia areata can mimic telogen effluvium, and a biopsy then shows inflammation around the follicles (DermNet). Many patients link it to stress. In a French survey of 96 people with alopecia areata, 54% named stress as a cause (Pellant et al. 2026). In a Swedish study of 100 patients, 82% reported at least one life event they rated as straining (undesirable, unexpected or uncontrollable) in the two years before onset (Fhager et al. 2026). Both relied on people remembering events after diagnosis, and neither had a matched comparison group, so they cannot show that stress causes alopecia areata.

Trichotillomania: hair pulling, not hair shedding

Trichotillomania is a body-focused repetitive behaviour in which people pull out their own hair, often to relieve tension. It produces broken hairs of different lengths in odd-shaped areas, and it needs behavioural treatment rather than hair-growth products. We cover it in detail in our trichotillomania evidence review.

Symptoms, diagnosis and red flags

What telogen effluvium looks like

• A sudden increase in hairs on the brush, pillow or shower drain, usually noticed after washing (BAD).
• Thinning all over the scalp rather than bald patches. Up to half of scalp hair can be affected, but it does not cause complete baldness (DermNet).
• Shed hairs with a small white bulb at the root (a "club" hair).
• Sometimes scalp tenderness or altered sensation, called trichodynia (BAD).
• Often a fringe of short new hairs along the hairline as regrowth starts. As DermNet notes, the shedding is itself a sign of regrowth, because new hairs push the old ones out (DermNet).

Most people lose roughly 50 to 100 hairs a day without noticing (NHS); the BAD gives a normal range of 30 to 150 (BAD).

How it is diagnosed

Diagnosis is usually made from the history and the look of the scalp. A doctor may do a gentle pull test; it can be falsely negative if hair was washed in the previous 48 hours. Hairs may be examined under a microscope, and a biopsy is rarely needed. Blood tests may be used to exclude other causes, such as thyroid disease and iron deficiency (BAD). DermNet adds vitamin B12 and folate to the list of abnormalities to correct (DermNet).

A small clue: a stress or illness that briefly halts hair growth can also leave a groove across the fingernails (a Beau line). Because a fingernail takes about 5 months to grow out, the position of the groove can date the trigger (DermNet).

Causes and risk factors

Psychological stress is one trigger among many. The BAD and DermNet list these common causes (BAD; DermNet):

• Childbirth. Postpartum shedding is a classic form. It usually resolves after a few months but can unmask female pattern hair loss.
• Illness, especially with fever, including COVID-19 (Jeon 2025).
• Surgery, accidents and severe trauma.
• Stressful or major life events.
• Rapid weight loss, crash diets and nutritional deficiency, especially iron.
• Thyroid disease, either underactive or overactive.
• Starting new medicines, or stopping hormone treatment such as the contraceptive pill.
• Scalp skin disease and, less commonly, jet lag or heavy sun exposure.

In about 1 in 3 people with telogen effluvium no cause is found (BAD). Because illness and life upheaval often happen together, it is frequently impossible to know whether the stress or the physical event was the main trigger.

Iron, vitamin D and other nutrients

Observational studies report lower ferritin and vitamin D in people with telogen effluvium than in controls. We could not locate the 2026 pooled analysis first cited here, so we do not quote its figures. These studies show an association, not that supplements fix the shedding. The BAD notes that shedding can recur if an underlying cause such as iron deficiency is not treated (BAD).

Telogen effluvium and pattern hair loss

The two often overlap. A telogen shed can be the first sign that reveals underlying male or female pattern hair loss, and repeated episodes can evolve into it (BAD; DermNet). This matters because pattern hair loss does respond to treatment, while pure telogen effluvium recovers by itself.

How stress affects hair: people vs mice

Popular articles often say "cortisol kills hair follicles". The evidence is more limited than that.

What is shown in mice

The most-cited study is a 2021 paper in Nature from Harvard researchers. In mice, the adrenal stress hormone corticosterone (the rodent equivalent of human cortisol) kept hair follicle stem cells resting for longer. Removing the adrenal glands made the stem cells cycle more often throughout life. Chronic stress raised corticosterone and held follicles in an extended resting phase. The hormone acted on the dermal papilla, a cluster of cells at the base of the follicle, to switch off a gene called Gas6. Restoring GAS6 overcame the stress-induced block on hair growth (Choi et al. 2021). The work was funded by several US National Institutes of Health institutes (Europe PMC).

Other mouse work points to a different stress hormone, corticotropin-releasing hormone, acting on follicles through cell-recycling (autophagy) pathways (Liang et al. 2024). That study was funded by the National Natural Science Foundation of China and Shantou University Medical College.

What is shown in people

In humans, the evidence is clinical and observational. Dermatologists see shedding a few months after major stress, and patients with alopecia areata often report earlier stressful events (Fhager 2026). We found no human trial showing that lowering cortisol, or boosting GAS6, prevents or reverses stress shedding. Mouse hair cycles differ from human ones, and the Choi study was designed to explain biology, not to test a treatment. Any product claiming to "block stress hormones to regrow hair" is going beyond the evidence.

What works and what does not

Treatments: recovery, minoxidil and medicines

Time and reassurance

For acute telogen effluvium, the treatment that has the strongest support is not a product. The BAD states that no treatment is normally needed, that the hair will start to regrow naturally, and that medication does not speed regrowth (BAD). DermNet says shedding peaks and then tapers back to normal over 6 to 9 months in most cases, though recovery is sometimes incomplete (DermNet). The NHS notes that hair loss caused by a medical condition usually stops or grows back after recovery (NHS).

Practical steps advised by the BAD include gentle brushing, limiting heat styling, bleaching and tight hairstyles, stopping smoking, a balanced diet rich in iron and protein, and considering supplements only if the diet is restricted, for example vegan or vegetarian (BAD). Volumising shampoo and hair fibres can disguise thinning. The NHS suggests GP help with counselling if hair loss affects wellbeing (NHS).

Managing the stress itself

There is no trial showing that stress-reduction programmes speed regrowth in telogen effluvium. They are still worth considering for their own sake, because persistent stress and anxiety affect health more widely. Psychological treatments such as cognitive behavioural therapy and mindfulness-based therapy have their own evidence bases, which we review separately.

Topical minoxidil

Minoxidil is the best-studied over-the-counter hair treatment, but almost all of its evidence is in pattern hair loss. The 2016 Cochrane review of female pattern hair loss pooled six trials: 157 of 593 women on minoxidil reported moderate to marked regrowth, against 77 of 555 on placebo (risk ratio 1.93, 95% CI 1.51 to 2.47; moderate-quality evidence). Total hair count rose by 13.18 hairs per cm² more than placebo (95% CI 10.92 to 15.44; low-quality evidence) (van Zuuren et al., Cochrane 2016). In plain terms, roughly twice as many women saw meaningful regrowth with minoxidil as with placebo. We could not confirm the review's own funding or author declarations; the review reports that 26 of its 47 included trials were funded, mainly by pharmaceutical companies.

The NHS notes minoxidil only works for as long as it is used (NHS). The US women's foam label says results may take 3 months, and that some women need at least 6 months of use before they see results (DailyMed). Because pure telogen effluvium usually recovers by itself within a similar time frame, any apparent benefit in that condition would be hard to separate from natural recovery without a placebo group.

Low-dose oral minoxidil

Oral minoxidil tablets are licensed only as a powerful blood-pressure medicine for hard-to-treat hypertension (DailyMed label). Dermatologists now prescribe much smaller doses off-label for hair loss.

For chronic telogen effluvium, the only study we found was a retrospective series from Australia. Thirty-six women took 0.25 to 2.5 mg daily. Their hair shedding score fell by 1.7 points at 6 months and 2.58 points at 12 months from a baseline of 5.64. Thirteen (abstract) or fourteen (results section) developed facial hair growth (Perera & Sinclair 2017). There was no control group. The paper declares no grants, but the senior author disclosed that he directs Samson Clinical Pty Ltd, which owns a patent application titled 'Detection and treatment of excessive hair shedding'.

In pattern hair loss, a double-blind trial in men at one Brazilian clinic compared 5 mg oral minoxidil daily with 5% topical minoxidil twice daily for 24 weeks (Penha et al. 2024). Oral minoxidil was not shown to be superior to topical minoxidil. We could not retrieve the density figures or the funding statement, so we do not quote them.

Supplements and lifestyle claims

Biotin

Biotin (vitamin B7) is the ingredient most associated with hair. A 2017 review found 18 reported cases of biotin helping hair or nails, but every patient had an underlying problem such as biotin deficiency or a rare hair-shaft condition. The authors found insufficient evidence for supplementation in healthy people (Patel et al. 2017). A 2024 review found only three studies of oral biotin for hair; the highest-quality, a double-blind placebo-controlled trial, found no difference between biotin and placebo. The authors described a large gap between public belief and the science (Yelich et al. 2024). That review had no funding and no declared conflicts.

A tiny Brazilian crossover study in 10 healthy men found that 5 mg biotin alone for 14 days did not change hair growth rate (Valentim et al. 2024). No financial support was declared. It was too small and short to settle anything, but it points the same way.

Multi-ingredient hair supplements

A 2023 systematic review in JAMA Dermatology examined 30 studies of nutritional supplements for hair loss in people without a known deficiency. It reported that the highest-quality studies suggested possible benefit for several products, including Viviscal, Nourkrin, Nutrafol, Lamdapil and Pantogar, as well as zinc and pumpkin seed oil. Side effects were rare and mild. The authors called for larger trials with active comparators (Drake et al. 2023). As reported in medical press coverage, the review noted that the marine-protein products' studies were funded by their manufacturers and not well controlled (The Hospitalist). None of the included studies tested these products specifically in diagnosed telogen effluvium caused by stress.

Nutrafol's own trials illustrate the pattern. A 6-month trial in 40 women with self-perceived thinning (26 on the supplement, 14 on placebo) reported more terminal and vellus hairs at days 90 and 180 (Ablon & Kogan 2018); the co-author was affiliated with Nutraceutical Wellness, Nutrafol's maker. A 2025 men's trial reported more participants rated as improved by blinded investigators (Bhatia et al. 2025). That trial was funded by Nutraceutical Wellness, and at least one author is a Nutrafol company executive. These are manufacturer-funded results and have not been independently replicated.

Iron and vitamin D

Correcting a measured deficiency is reasonable and is what the BAD and DermNet advise. Taking iron "just in case" is a different matter; iron can cause harm in people who do not need it, including those with iron overload (see our haemochromatosis review). For vitamin D, see our vitamin D evidence review.

Collagen, "adaptogens" and stress-relief blends

We found no independent trial in telogen effluvium for collagen powders or the "adaptogen" botanicals used in hair blends. Our collagen review covers the wider skin and joint evidence.

Risks of common treatments

Topical minoxidil

The US women's foam label advises stopping and asking a doctor for chest pain, a racing heart, faintness, dizziness, sudden weight gain, swollen hands or feet, scalp irritation or unwanted facial hair. It states the product may be harmful in pregnancy or breastfeeding, is not for under-18s, and should be kept away from children and pets. Some users notice changes in hair colour or texture (DailyMed).

Supplements

Adverse effects in hair-supplement trials were described as rare and mild (Drake 2023), but trials are small and short. The main practical harms are hidden biotin, unnecessary iron, and the cost of long subscriptions for an unproven benefit. Supplements are not checked for effectiveness before sale. For how to judge product quality and liver safety, see our guide to drug and supplement liver injury.

Who to see

• GP or primary-care doctor first. The NHS advises seeing a GP if you are worried, and before going to a commercial hair clinic. The GP can often tell the cause by looking, and can arrange blood tests (NHS).
• Dermatologist for patchy or scarring hair loss, diagnostic doubt, shedding beyond 6 months, or severe alopecia areata. In England, NICE recommends ritlecitinib for severe alopecia areata in people aged 12 and over, subject to the manufacturer's commercial arrangement (NICE TA958).
• Psychological support if hair loss is affecting mood, or if stress, anxiety or hair pulling is the main problem. Patient groups such as Alopecia UK are listed by the BAD (BAD).
• Midwife, health visitor or GP after childbirth, especially if shedding comes with low mood. Postnatal depression is common and treatable; see our perinatal depression review.
• Pharmacist before starting minoxidil or a supplement alongside other medicines, and before blood tests if you take biotin.

Follow the money: who funds the research and who sells the treatments

Who funds the research

The basic science on stress and hair is largely publicly funded. The key mouse study was supported by multiple NIH institutes (Europe PMC), and the Cochrane review's included trials were mostly pharma-funded (its own funding was not confirmed) (Cochrane). The best recent oral minoxidil trial had a small single-clinic design, and we could not confirm its funding (Penha 2024). Minoxidil itself is long off-patent and cheap, so there is little commercial incentive to run large placebo-controlled trials of it in telogen effluvium. The one study of oral minoxidil in chronic shedding came from a clinician whose company holds a patent application on excessive hair shedding treatment (Perera & Sinclair 2017).

The supplement evidence is the opposite. In the 2023 systematic review, the marine-protein products' studies were funded by their manufacturers (The Hospitalist), as were Nutrafol's, and two of the review's authors reported pharmaceutical-industry ties, outside the submitted work. Nutrafol's placebo-controlled trials were funded by its maker and co-authored by at least one of its executives (Bhatia 2025).

Guideline panels

We found no NICE guideline or UK national guideline specifically for telogen effluvium. The most authoritative UK patient advice comes from the British Association of Dermatologists, a professional body whose leaflets are written by its members and reviewed by a lay panel (BAD). The leaflet lists no individual author conflicts, and we did not audit the BAD's corporate sponsorship. NICE's appraisal recommends the drug only if the company supplies it under the agreed commercial arrangement (NICE TA958).

Who sells the products: the Nutrafol example

• Owner. The consumer-goods group Unilever announced in late May 2022 (trade press dates it 31 May) that it would buy a majority stake in Nutrafol. It already held 13.2% through Unilever Ventures. Nutrafol had been backed by the private equity firm L Catterton and stays based in New York under CEO Giorgos Tsetis. Terms were not disclosed (Unilever; NutraIngredients).
• Sales channels. Trade press coverage of the deal reported a network of more than 3,000 physicians who sell Nutrafol (Beauty Packaging). Doctors who sell a supplement have a financial interest in recommending it.
• Marketing. Nutrafol's promotional wording, including 'dermatologist recommended' and 'medical-grade', is the company's own claim, not an independent finding. We could not confirm the exact wording in the company release.
• Maker of the trials. The trials are run by Nutraceutical Wellness Inc., Nutrafol's operating company (Bhatia 2025).

Documented integrity events

• The consumer group Truth in Advertising (TINA.org) first flagged Nutrafol's marketing in 2020. In December 2022 it criticised the brand's "clinically proven" hair-growth claims and influencer posts without clear ad disclosures (TINA.org), and in April 2023 it filed a complaint with the FDA and FTC (TINA.org complaint). These are TINA.org's allegations; we found no FTC or FDA action resulting from them.
• Class actions filed in the Southern District of New York in 2023 against Nutraceutical Wellness alleged misleading "clinically proven" and "medical grade" claims. TINA.org lists Smith et al. (May 2023) as settled and dismissed (tracker), and Sheehan et al. and Malich et al. as pending when we checked (Sheehan; Malich). Allegations are not findings of wrongdoing, and we could not view court filings to confirm the current status.
• For biotin, the FDA has named specific troponin test makers whose assays had not addressed biotin interference (FDA).

What this means: The advice to wait, look for a trigger and treat confirmed deficiencies comes from public bodies and professional organisations with nothing to sell. The positive case for hair supplements rests mainly on trials paid for by the companies that sell them, owned in Nutrafol's case by one of the world's largest consumer-goods groups. The case for oral minoxidil in chronic shedding rests on a single uncontrolled study by a clinician with a patent interest. None of that proves the products do not work. It does mean their benefit for stress shedding has not been independently shown.

Related research

For wider, evidence-graded context, see these Pure City Research guides:

• Trichotillomania (hair-pulling disorder)
• Excoriation (skin-picking) disorder
• Stress and physical health
• Occupational burnout
• Generalised anxiety disorder
• Perinatal and postpartum depression
• Supplements for stress, anxiety and depression
• Stress, anxiety and depression: evidence and care options
• Collagen: skin, joint and bone evidence
• Vitamin D: deficiency, benefits and safety
• Troponin and other cardiac blood tests
• Haemochromatosis: iron overload

Frequently asked questions

Sources and funding notes

What we could not verify: Figures removed after checking: the 2026 Ahmed iron and vitamin D meta-analysis (not found), the Jeon prevalence numbers, the Penha density, side-effect and funding figures, the Drake individual consultancy names and tocotrienol, and the Nutrafol promotional quotes. The Cochrane review's own funding statement was not confirmed. Chen 2025, Valentim 2024, Patel 2017 and the full topical minoxidil side-effect list were not individually rechecked. We could not open the NIH StatPearls chapter on telogen effluvium, the NIH Office of Dietary Supplements biotin fact sheet or the original 2017 and 2019 FDA biotin safety communications (access was blocked), so we relied on the current FDA troponin-assay page and trade-press reporting of the 2019 update. We did not see funding statements for Daunton 2023, Pellant 2026, Vañó-Galván 2021 or Chen 2025, or Ablon & Kogan 2018, or the full disclosure section of Drake 2023 (we used reported disclosures). We found no controlled trial of any treatment specifically in acute stress-related telogen effluvium, and no NICE guideline on it. We could not verify Nutrafol's revenue, Unilever's exact current stake, the outcome of the pending class actions, TINA.org's major donors, or any FTC or FDA response to TINA.org's complaint. The BAD's corporate sponsorship was not audited.

1. British Association of Dermatologists. Telogen effluvium patient information leaflet (updated October 2025) — UK professional body; income not audited.
2. NHS. Hair loss (reviewed 24 January 2024) — UK public health service; taxpayer-funded.
3. DermNet. Telogen effluvium — New Zealand dermatology reference; carries advertising.
4. US FDA. Biotin interference with troponin lab tests (content current as of 21 June 2022) — US regulator.
5. Clinical Lab Products. FDA updates biotin interference warning (5 November 2019) — trade press reporting the FDA update; advertising-funded.
6. DailyMed. Minoxidil for women 5% foam, US OTC label — manufacturer label under FDA rules; hosted by US NLM.
7. DailyMed. Minoxidil tablets, US prescribing information — FDA-approved label with boxed warning.
8. NICE TA958. Ritlecitinib for treating severe alopecia areata in people 12 years and over (27 March 2024) — UK public body; based partly on manufacturer (Pfizer) submission.
9. van Zuuren EJ et al. Interventions for female pattern hair loss. Cochrane 2016 — systematic review; review funding not confirmed; most included trials pharma-funded.
10. Choi S et al. Corticosterone inhibits GAS6 to govern hair follicle stem-cell quiescence. Nature 2021 — mouse study; US NIH grants (grant list).
11. Liang W et al. Psychological stress induces hair regenerative disorders through CRH-mediated autophagy inhibition. 2024 — mouse study; National Natural Science Foundation of China.
12. Jeon JJ et al. Global epidemiology of telogen effluvium after the COVID-19 pandemic. JAAD Int 2025 — systematic review letter; National Research Foundation of Korea per dataset listing; conflicts not verified.
13. TINA.org. Hair-raising claims by Unilever's Nutrafol reported to regulators (5 April 2023) — US consumer-advocacy non-profit; complaint to FDA and FTC.
14. Daunton A et al. Chronic telogen effluvium: is it a distinct condition? Am J Clin Dermatol 2023 — systematic review; funding statement not seen.
15. Pellant M et al. Perceived stress, illness and stigma in alopecia areata. Acta Derm Venereol 2026 — French survey; funding not seen.
16. Fhager J et al. Life events preceding alopecia areata onset. Clin Cosmet Investig Dermatol 2026 — Swedish retrospective cohort; no conflicts declared.
17. Penha MA et al. Oral vs topical minoxidil for male androgenetic alopecia. JAMA Dermatol 2024 — RCT; funding statement not confirmed.
18. Perera E, Sinclair R. Treatment of chronic telogen effluvium with oral minoxidil. F1000Research 2017 — retrospective series; no grants; author's company owns related patent application.
19. Vañó-Galván S et al. Safety of low-dose oral minoxidil for hair loss: 1,404 patients. J Am Acad Dermatol 2021 — retrospective series; funding not seen.
20. Chen M et al. Low-dose oral minoxidil and blood pressure: systematic review and meta-analysis. J Am Acad Dermatol 2025 — funding not seen.
21. Patel DP et al. A review of the use of biotin for hair loss. Skin Appendage Disord 2017 — academic review.
22. Yelich A et al. Biotin for hair loss: teasing out the evidence. J Clin Aesthet Dermatol 2024 — no funding; no conflicts.
23. Valentim FO et al. Topical minoxidil vs oral biotin vs both in men. An Bras Dermatol 2024 — 10-person crossover study; no financial support declared.
24. Drake L et al. Nutritional supplements for treating hair loss: a systematic review. JAMA Dermatol 2023 — academic; two authors report pharmaceutical-industry ties (as reported) (reported disclosures).
25. Ablon G. Six-month RCT of a nutraceutical supplement in women with self-perceived thinning. J Drugs Dermatol 2018 — co-author affiliated with Nutraceutical Wellness (maker); funding statement not seen.
26. Bhatia N et al. RCT of a nutraceutical supplement in males with thinning hair. J Cosmet Dermatol 2025 — funded by Nutraceutical Wellness; at least one author is a Nutrafol executive.
27. Unilever. Unilever to acquire majority stake in Nutrafol (late May 2022) — company press release.
28. NutraIngredients. Unilever acquires majority stake in Nutrafol (13 June 2022) — trade press; advertising-funded.
29. TINA.org. Nutrafol needs to shed its deceptive hair growth claims (updated May 2023) — US consumer-advocacy non-profit.
30. TINA.org class-action tracker: Smith et al. v. Nutraceutical Wellness; Sheehan et al.; Malich et al. — advocacy group records of court cases.
31. The Hospitalist. Review gives weight to supplements for hair loss — medical news coverage of Drake 2023, including disclosures.
32. Cochrane commercial sponsorship policy — Cochrane.

Educational research reviewed 6 October 2026. This article is not medical advice; talk to a qualified clinician or pharmacist before starting, stopping or combining treatments.