# Hair Experts — The Shed Clock

> Sourced timelines for when hair shedding typically starts, peaks and settles after specific triggers. Educational only — not medical advice.

Editorial guidance: William Gaunitz. Page-level review in progress.
Machine-readable data: https://hairexperts.org/data/timelines.json

## Triggers
## Hubs
- [Medications](https://hairexperts.org/triggers/medications/)
- [Life events & procedures](https://hairexperts.org/triggers/life-events/)

- [Hair shedding after starting a GLP-1 medication](https://hairexperts.org/triggers/glp-1-medications/): Hair loss is listed in the Wegovy (semaglutide 2.4 mg) prescribing information in about 3% of adults versus 1% on placebo, and the label says these reports were associated with weight reduction; weight loss is a recognised trigger of telogen effluvium, which typically shows a few months after the trigger.
- [Hair shedding after giving birth](https://hairexperts.org/triggers/postpartum/): Postpartum shedding is commonly noticed about two months after giving birth, usually peaks around four months, and is normal and temporary, with hair tending to regain its fullness within six to nine months.
- [Hair shedding after surgery](https://hairexperts.org/triggers/after-surgery-anesthesia/): Hair shedding after an operation is usually telogen effluvium, which is typically noticed 2 to 4 months after the surgery and commonly tapers back to normal over 6 to 9 months.
- [Hair shedding after starting minoxidil](https://hairexperts.org/triggers/starting-minoxidil/): A temporary increase in shedding is commonly reported in the first weeks of minoxidil — the so-called 'dread shed' — and in one 2025 study of topical minoxidil it peaked around week 4 and was below baseline by week 16.
- [Hair shedding after stopping finasteride](https://hairexperts.org/triggers/stopping-finasteride/): According to the Propecia (finasteride 1 mg) FDA label, withdrawal of treatment leads to reversal of its effect within 12 months, so hair it was maintaining typically returns toward the untreated pattern gradually over that year.
- [Zepbound hair loss at month 3: where tirzepatide shedding sits on the clock](https://hairexperts.org/triggers/mounjaro-zepbound-tirzepatide/): The Zepbound label lists hair loss in 4–5% of patients versus 1% on placebo, far more often in women (7.1%) than men (0.5%), and says it was associated with weight reduction; weight-loss shedding is typically noticed 2–4 months after the loss begins.
- [Hair loss after gastric sleeve at month 4: what the studies tracked](https://hairexperts.org/triggers/gastric-sleeve-bariatric-surgery/): In a study of 156 women after sleeve gastrectomy, 72% reported hair loss, 79% of them starting between the third and fourth month, lasting an average of 5.5 months, with no permanent hair loss seen.
- [Hair loss after stopping breastfeeding: is it a second shed?](https://hairexperts.org/triggers/stopping-breastfeeding/): HealthLink BC notes that, because of hormone changes, people often lose hair for 1 to 6 months after childbirth or after they stop breastfeeding; Johns Hopkins adds that breastfeeding can lengthen the shedding period.
- [Hair shedding after stopping birth control: why it shows up months later](https://hairexperts.org/triggers/stopping-birth-control/): When a woman stops oral contraceptives, shedding may begin 2 or 3 months later and continue for about 6 months before it usually stops, according to HealthLink BC; the AAD lists stopping the pill among common shedding triggers.
- [Hair loss 2 months after COVID or a high fever: why it shows up then](https://hairexperts.org/triggers/covid-high-fever/): After COVID-19, hair shedding usually begins 2 to 3 months later and lasts 3 to 6 months (AAD); a JAAD case series found onset at a median of 45 days, somewhat earlier than after other triggers.
- [Hair loss after a crash diet: the delayed bill for rapid weight loss](https://hairexperts.org/triggers/crash-diet-fasting/): Losing 20 pounds or more is a common trigger of excessive shedding (AAD), and NICE lists excessive diets among telogen effluvium triggers, which typically appears around 3 months after the trigger and lasts about 6 months.
- [What happens when you stop minoxidil: back to baseline in 3–4 months](https://hairexperts.org/triggers/stopping-minoxidil/): If minoxidil is stopped, the pretreatment appearance normally returns within 3 or 4 months, and after several years of use the hair that was genetically programmed to be lost in that time will fall out (DermNet).
- [Hair transplant shock loss, week by week](https://hairexperts.org/triggers/hair-transplant-shock-loss/): Shock loss (recipient-site effluvium) — shedding of native hairs around the grafts — typically occurs 2–8 weeks after surgery, with regrowth usually starting around 3 months; reported incidence ranges from 0.15% to 15%.
- [Lamotrigine hair loss: how long after starting it shows up](https://hairexperts.org/triggers/lamotrigine/): In a review of pharmacovigilance reports of lamotrigine-associated alopecia, onset was variable: 17 people within one month, 48 between one and six months, and 31 after six months of starting.
- [Depakote (valproate) hair loss: the anti-seizure drug most linked to it](https://hairexperts.org/triggers/valproate-depakote/): DermNet lists valproic acid as causing hair loss in 12–28% of users, dose-dependently, among the highest rates of any anticonvulsant; a review of anti-seizure medicines found valproate was the drug most commonly associated with alopecia in one paediatric series.
- [Accutane hair loss and dose: what a systematic review counted](https://hairexperts.org/triggers/isotretinoin-accutane/): A systematic review of 22 studies found hair loss in 3.2% of acne patients on isotretinoin below 0.5 mg/kg/day versus 5.7% on 0.5 mg/kg/day or more, and recommended counselling about telogen effluvium before starting.
- [Sertraline hair loss after 2 weeks: rare, but reported](https://hairexperts.org/triggers/sertraline-ssris/): Hair loss is a rare reported side effect of sertraline; one published case described diffuse hair loss within 2 weeks of starting that improved after the drug was stopped, and NICE lists antidepressants among drugs implicated in telogen effluvium.
- [Does Eliquis cause hair loss? What's known about blood thinners](https://hairexperts.org/triggers/anticoagulants-eliquis-xarelto-warfarin/): DermNet lists heparin and warfarin among drugs that cause telogen effluvium and says newer anticoagulants such as rivaroxaban, dabigatran and apixaban possibly do; NICE also lists anticoagulants as a telogen effluvium trigger.
- [Levothyroxine hair loss in the first months of treatment](https://hairexperts.org/triggers/levothyroxine-dose-change/): Levothyroxine labelling says partial hair loss may occur rarely during the first few months of therapy and is usually temporary.
- [Ferritin level for hair loss: the numbers studies use](https://hairexperts.org/triggers/ferritin-hair-loss/): One study of 155 women with hair loss defined iron deficiency as ferritin below 60 ng/mL and cited 40–60 ng/mL as the adequate level for hair growth — much higher than the level linked to anaemia — but thresholds differ, so ask your doctor about testing.
- [Vitamin D deficiency and hair loss: mixed evidence, worth asking about](https://hairexperts.org/triggers/vitamin-d-hair-loss/): A case-control study of women with female pattern hair loss classed vitamin D below 20 ng/mL as deficient and 20–30 as insufficient, and its background notes conflicting results — including a New Zealand study of 296 men that found no link with male pattern alopecia.
- [Hair shedding in September? The seasonal shed is real](https://hairexperts.org/triggers/seasonal-hair-shedding/): In a UK study of 14 men, shed hairs peaked around August–September at about 60 a day, more than double the preceding winter; a study of 823 women found the proportion of resting (telogen) hairs peaked in summer, with a smaller peak in spring.
- [Is traction alopecia from braids reversible? It depends how long](https://hairexperts.org/triggers/braids-traction-alopecia/): Traction alopecia can get better when it has only been present for a few weeks or months if the tension is stopped, but long-term repetitive pulling can cause permanent loss from follicle damage (British Association of Dermatologists).
- [White bulb on the hair root? That's a telogen club hair](https://hairexperts.org/triggers/telogen-club-hair/): A shed hair with a small white bulb at the root is a resting (telogen) 'club' hair; DermNet explains that in telogen effluvium these are pushed out by new growth, so increased fall is paradoxically a sign of regrowth.
- [Is it regrowth or breakage? Reading the short hairs](https://hairexperts.org/triggers/regrowth-vs-breakage/): A fine fringe of short new hairs along the hairline is a common sign of recovery after telogen effluvium (DermNet), while broken hairs around the forehead are an early warning sign of traction hair loss (AAD).

## Tools
- [Shed Clock calculator](https://hairexperts.org/calculator/)

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