The first thing to know: everyone loses hair every day, all year, forever. Somewhere between 50 and 100 hairs a day is normal turnover. Those hairs on the pillow and in the shower drain were always going to fall. What matters is a change: noticeably more hairs coming out for weeks, a widening part, a receding line, or patches. That is when the cause matters, because different causes have very different timelines and treatments.
The seven causes
Common causes of hair loss
- Telogen effluvium. A shed triggered two or three months after a body shock: a bad flu or COVID, surgery, high fever, crash dieting, or a period of serious stress. Large numbers of hairs shift into the resting phase at once and then fall together. It looks alarming and it usually fixes itself within six to twelve months.
- Low iron and other shortages. Low ferritin is one of the most common findings in women with diffuse thinning. Vitamin D and zinc matter too, and restrictive diets cause shedding on their own. A blood test settles it, and treating a real deficiency works.
- Hormones. An overactive or underactive thyroid, the months after childbirth, and conditions like PCOS all shift hair cycles. Postpartum shedding peaks around three months after the birth and resolves for most women within the year.
- Genetic pattern loss. Androgenetic alopecia, the family kind. In men it recedes and thins at the crown; in women the part widens and volume drops at the top while the front hairline usually holds. It starts any time after the late teens and progresses slowly. It responds to treatment, though treatment means ongoing, not a cure.
- Medication side effects. Some drugs list hair loss among their side effects, including certain acne treatments, blood thinners, and of course chemotherapy. Never stop a prescribed medicine over hair; talk to the GP about alternatives first.
- Traction and processing. Very tight ponytails, braids and weaves, plus heavy extensions, pull on follicles for years and can thin the hairline permanently. Heat and chemical treatments usually break the shaft rather than shed the root. A quick test: a shed hair has a little white bulb at one end; a broken one does not.
- Alopecia areata. Smooth round patches that appear over days or weeks, caused by the immune system attacking follicles. It needs a doctor promptly, because early treatment works better.
The honest timeline
Regrowth after telogen effluvium
Stress-related shedding follows a predictable path, and knowing the shape of it stops most of the panic.
| Time since trigger | What happens |
|---|---|
| Months 0 to 2 | Nothing visible. The hairs have left the growing phase but have not fallen yet. |
| Months 2 to 3 | Shedding starts, often suddenly: hair in the brush, on clothes, in the drain. |
| Months 3 to 6 | Peak shedding. It often looks worse before it looks better. This is the phase people search at midnight. |
| Months 6 to 9 | Shedding slows back toward normal. First short new hairs appear along the hairline. |
| Months 9 to 12 | Regrowth becomes visible in length and density. Most people fully recover inside a year. |
If heavy shedding continues past six months, ask a GP for bloods: ferritin, vitamin D, thyroid function and zinc cover the usual suspects. Chronic shedding has the same triggers at a lower simmer, and it is very treatable once the underlying shortage or condition is found.
What actually helps
Treatments worth your time
Hair loss treatments with real evidence behind them are few. These are the ones that matter, and the order they belong in.
Bloods before supplements
Get tested first. Treating a real iron or vitamin D deficiency grows hair; taking biotin without a deficiency does nothing except make expensive urine, and high-dose biotin also interferes with some lab tests. Tell your doctor you take it if you do.
Minoxidil
The non-prescription option with the strongest evidence. It takes three to six months of daily use before anyone else notices a difference, and gains fade if you stop. A short burst of extra shedding in the first weeks is the treatment working, not failing. Not for use in pregnancy or while trying to conceive.
Gentler handling
Looser styles, less heat, and patience with wet hair, which stretches and snaps. None of this regrows hair, but it stops handing new losses to traction and breakage while the underlying cause settles.
Female hair loss looks different
Female pattern loss rarely recedes. The part widens, the ponytail gets thinner, and the front hairline mostly stays, which is why it often gets noticed late, by a hairdresser. It runs in families on either side, it can begin as early as the twenties, and minoxidil is the main over-the-counter response. A GP visit is worth it early, because thyroid and iron problems can stack on top of it and make it look worse than it is.
When to act sooner
See a doctor soon rather than later
This page is general information, not medical advice, and it replaces nothing a GP or dermatologist can tell you looking at your actual scalp.
FAQ
Quick answers
How much hair loss per day is normal?
Between 50 and 100 hairs. Pillow, brush and drain hairs count toward that total.
Will hair grow back after stress-related loss?
Usually yes. Shedding settles within three to six months and regrowth is visible by six to twelve months for most people.
Does wearing hats cause hair loss?
No. Only constant tight pulling from hairstyles and heavy extensions causes traction loss.
How long does minoxidil take to work?
Three to six months of daily use. Early shedding is expected and temporary.
When should I see a doctor?
For patches, scalp pain, itching, very rapid loss, or shedding with fatigue and weight changes.