June 25, 2026 Kiran Nagra

Why Is My Hair Falling Out? The Real Reasons Behind Hair Loss in Women Over 40

She runs her fingers through her hair in the shower and a small raft of it comes away in her hand. It's on the pillow, in the brush, gathering at the drain in a way it never used to. She's somewhere in her forties, and the question she arrives with is almost always the same, and almost always slightly panicked: am I going bald?

Hair loss in women is one of the most distressing and least-well-explained things I see, partly because the cultural script around it is written for men — a receding hairline, a bald crown — and that's not usually what's happening to women at all. What women experience is more often a diffuse thinning, a loss of density across the whole head, more scalp showing in the part line, a ponytail that's lost its thickness. And the reasons behind it are genuinely different from the male story. Let me walk you through what's actually going on, because once you understand the mechanism, the panic usually drops several notches — and the path forward gets a lot clearer.

Hair is on a clock, and the clock is the key to everything

Here's the single fact that reframes the whole conversation. Your hair is not growing continuously. Every follicle is on a cycle, moving through phases: a long growing phase that lasts years, a brief transition, and then a resting phase of a few months, at the end of which the hair is released and a new one begins. At any given time, the vast majority of your follicles — around 85 to 90% — are in the growing phase, and a small minority, perhaps 10%, are resting and shedding. That's why you normally lose some hair every day and never notice. It's a staggered system, like a forest where only a few trees drop their leaves at once while the rest stay green.

Now imagine something hits that forest all at the same time — a frost, a drought. A large block of trees that would have dropped their leaves on their own schedule, spread out over months, suddenly all turn at once. That's telogen effluvium, and it is the single most common cause of sudden diffuse shedding in women. A physiological stress — and the menu of triggers is long — pushes an abnormally large fraction of follicles out of the growing phase and into resting together. They then shed together, in a frightening rush.

The cruel time delay that hides the cause

Here's the part that catches almost everyone out, and it's the most useful thing in this entire article. The resting phase lasts about two to four months. So the shedding doesn't happen at the moment of the stress — it happens two to four months after it. By the time the hair is visibly coming out, the event that caused it is often long over and forgotten.

This is why women so often can't connect the dots. The big shed in October traces back to a bout of flu, a crash diet, a surgery, a bereavement, a course of a new medication, or a stretch of brutal sleeplessness back in July. The trigger has packed up and left town months before the evidence shows up at the crime scene. I cannot tell you how often the consultation turns a corner the moment we lay out a timeline and walk backwards — "what was happening in your life about three months before this started?" — and a woman's face changes as she remembers the thing she'd stopped thinking about. Childbirth is the classic, textbook version (the postpartum shed at three to four months), but the same delayed mechanism applies to any significant physical or emotional shock.

And here's the reassuring half of telogen effluvium: those follicles are not dead. They're resting, not gone. In most cases, once the underlying stress resolves, they cycle back into growth and the density returns over the following months. It is, more often than not, a temporary alarm — but the delay is what makes it feel like a catastrophe.

Then there's the perimenopause layer — a different mechanism entirely

For women over forty, there's a second process that often runs alongside the shedding story, and it's worth keeping the two separate in your mind because they behave differently. As a woman moves through the perimenopausal transition, estrogen — which has been quietly protective of the hair follicle, helping keep it in that long growth phase — becomes more variable and then lower. As its steadying influence withdraws, the follicle becomes relatively more exposed to the body's androgens (the "male-pattern" hormones every woman also makes), even when those androgen levels are completely normal. It's not that androgens surge; it's that estrogen's counterbalance fades.

The result is follicle miniaturisation — the follicle doesn't die, but with each cycle it produces a slightly finer, shorter, less pigmented hair, until the strand is barely there. This is the slow, progressive thinning of the part line and the crown that characterises female-pattern hair loss, and it's a different beast from the sudden telogen shed. The shed is acute and usually recoverable; the miniaturisation is gradual and needs ongoing attention. Many women over forty are dealing with both at once — a telogen effluvium on top of an underlying perimenopausal thinning — which is exactly why this age group finds it so confusing.

The unglamorous culprits the mirror can't show you

This is the deep clinical layer, and it's where I spend most of my time, because the most common drivers of female shedding are not hair problems at all — they're whole-body signals showing up at the scalp. The follicle is one of the most metabolically demanding tissues in the body; it's spinning out a fast-growing fibre around the clock, which makes it an early casualty whenever the body decides to ration resources. So the hair becomes a kind of dipstick for what's happening underneath.

Two patterns dominate. The first is iron status — and specifically ferritin, the storage form of iron, not your standard blood count. This is the single most missed cause I see. A woman can have a perfectly normal haemoglobin and full blood count — "your bloods are fine" — while her ferritin, her iron reserves, are scraping the bottom. The body triages: iron goes to the red blood cells and the vital organs first, and the hair follicle, being non-essential to survival, is one of the first tissues to be starved when reserves run low. Recent research keeps confirming that ferritin tracks with telogen effluvium while haemoglobin does not — meaning the very test most likely to find the problem is the one not run by default. For menstruating and perimenopausal women, who lose iron monthly and often heavily in the perimenopausal years, this is enormous.

The second is the thyroid. The thyroid sets the metabolic tempo of nearly every cell, and the follicle is acutely sensitive to it. Both an underactive and an overactive thyroid can drive diffuse shedding, and thyroid issues rise sharply in women in exactly this age band — frequently sitting underneath a perimenopause label, because the symptoms overlap almost completely. Fatigue, weight change, mood, and hair — all of it can be thyroid wearing a perimenopause mask.

Around those two, a familiar supporting cast: rapid weight loss and very low-calorie dieting (a potent and underrated trigger — the body reads a crash diet as a famine and rations the follicle accordingly), low protein intake (hair is essentially structured protein, and you cannot build it from nothing), and shortfalls in zinc, vitamin D, B12 and selenium. Worth a current note, too: significant or rapid weight loss from any cause — including the newer weight-loss medications now so widely used — can itself precipitate a telogen shed, both through the rapid loss and sometimes through reduced nutrient intake along the way. That's not an argument against anything; it's a reason to be deliberate about protein and nutrient density when weight is coming off fast.

The test that finds it isn't the one you'll be offered

Here's the insider point. The reason hair loss feels so mysterious to so many women is that the workup that finds the cause is rarely the workup that gets done. A standard "your bloods are normal" can completely miss a low ferritin, an early thyroid shift, or a nutrient gap, because the default panel wasn't built to look for them. This isn't anyone's failing — it's a mismatch between a quick screen and a layered problem. A fuller look at iron reserves, thyroid function, and nutrient status is the conversation worth having when hair is genuinely thinning, and it's exactly the kind of broader picture a naturopathic assessment is oriented toward.

And the foundations matter more than any topical product: enough protein to actually build the fibre, enough iron-rich food (and the vitamin-C-rich foods alongside it that help you absorb it), not crash-dieting your follicles into a famine response, protecting sleep, and — because the hair clock is months long — patience, because nothing you do today shows up at the scalp for a season. The follicle you feed well in winter is the density you see in spring.

What this means for you

If your hair is shedding, the most powerful first move is not a shampoo — it's a calendar. Look back two to four months and ask what your body was dealing with. If it was a discrete event, there's a good chance the follicles are resting, not lost, and density will return as the stress resolves. If it's a slow, steady thinning at the part and crown, the perimenopausal hormone shift is more likely in the picture, and that's a longer game. Either way, the unglamorous drivers — iron reserves, thyroid, protein, crash diets — deserve looking at before anyone reaches for an exotic supplement, because they're common, they're correctable, and they're the ones routinely missed.

This is squarely the kind of multi-system pattern naturopathic and nutritional medicine is built to untangle, sitting alongside your GP for the medical pieces. Hair is patient and so is its recovery — but the right look at what's underneath usually changes the picture far more than anything you can buy off a shelf.

A few worth-knowing concepts

Hair grows on a cycle. Most follicles are growing while a small fraction rest and shed — which is why everyday hair loss is normal and invisible.
Telogen effluvium is the common shed. A stress flips a big wave of follicles into resting phase all at once, and they shed together months later.
The cause is two to four months back. The shedding lags the trigger, which is why women so often can't connect it to the illness, diet, or shock that caused it.
Perimenopause thins by a different route. Falling oestrogen lets normal androgens act more strongly on the follicle, causing gradual miniaturisation — separate from the acute shed.
Ferritin is the most-missed clue. Iron reserves can be flat while a standard blood count looks normal, and the follicle is one of the first tissues starved of iron.
Thyroid hides under perimenopause. Both under- and overactive thyroid drive shedding, and the symptoms overlap almost entirely with the menopausal transition.