It costs a couple of pounds a jar and it has been sat in British kitchen cupboards since your mother's time. Sheila B., 63, from Chesterfield, says the coffee on that shelf is the reason her parting has closed up for the first time since she turned sixty. Not drunk. Not swallowed in a tablet. Put on the scalp, in a fixed dose, two minutes morning and night. And she started in October — which she now believes was the whole point.

For most of last autumn, Sheila told herself it was the weather.

The brush she could explain away. The plughole she'd stopped properly looking at years ago. It was the pillow that finally stopped her, one Tuesday morning in the third week of October.

"You expect a few on the brush," she says. "You don't expect to lift your head and see a fan of them. Then peel another handful off the back of your jumper at half past nine."

Illustrative. What most women notice isn't the number — it's how much comes away in one go.

She counted, which she doesn't recommend. She got to about ninety before she gave up and rang her daughter.

What Sheila didn't know, and what almost no woman is told, is that she'd picked the worst possible month to panic — and, as it turns out, the best possible month to do something about it.

WHY SO MUCH MORE OF IT COMES OUT IN OCTOBER

Fiona M. has run a private trichology practice in Leeds for nineteen years. She says her phone does the same thing every autumn.

"From the middle of September to the end of November — that's when women ring. Every year. And every year they think something has gone badly wrong in the last fortnight."

The explanation is duller than the fright it causes. Every hair on a head runs on its own clock. It grows for a few years, then it rests, and some months after that it lets go so a new one can take its place. Hairs that went into their resting phase during the long days of May, June and July hit the end of that wait around three months later.

Which is now.

"Most of the year a woman sheds somewhere between fifty and a hundred hairs a day and never notices, because they leave one at a time," Fiona says. "At the peak of the autumn wave that can roughly double. A hundred, two hundred in a day. Nothing new is happening — it's simply arriving all at once."

The part worth understanding.The autumn shed isn't hair you're losing this month. It's hair you'd already finished with over the summer, leaving together. What actually decides how your parting looks by spring is whether those follicles start again.

And that, Fiona says, is why she'd rather see a woman in October than in March.

"A follicle that's just let a hair go is at a crossroads. It either starts the next one or it sits idle. On a woman in her sixties, with less blood reaching the scalp than she had at forty, a good number of them sit idle. Not dead. Idle. And the window where you can lean on that decision is a matter of weeks, not years."

THE QUOTE SHE DIDN'T BOOK

Sheila did what a sensible woman does. She booked a private consultation, because her GP surgery had already told her, kindly enough, that thinning hair isn't something the NHS treats.

£95for forty minutes, a bright lamp, and a set of photographs of her own scalp she wishes she'd never seen.

The recommendation was a twelve-week course of in-salon thickening treatments.£545.Plus the take-home products, which, she was told, reception could sort out on the way through.

£640 before she'd bought a single thing to use at her own sink.

"I'm not a poor woman," Sheila says. "But I'm sixty-three and my daughter is getting married in April. I sat in that car park and I thought — six hundred pounds. For hair."

She didn't book it. On the way out she got chatting to another woman in the waiting room who, as it turned out, hadn't booked it either. That woman told her what she'd been using since the spring instead.

THE JAR THAT WORKS, AND THE ONE THAT DOESN'T

What the woman named was a scalp spray — and the two things doing the work in it are caffeine and biotin. Coffee, in other words, and the vitamin half the country has been swallowing in tablet form for a decade.

Sheila's first reaction was to laugh at her.

"I said, I've got both of those. The coffee's by the kettle and the biotin's in the cupboard next to the ginger — which is the other thing everyone tells you to try."

She had tried the ginger, as it happens. Grated into hot water, for a fortnight, because her niece had read it somewhere. It did nothing whatsoever — and Fiona M. says she hears that one most weeks.

Illustrative. The kitchen remedy Sheila tried first. It's a story, not an ingredient — the spray contains caffeine and biotin, not ginger.

"Half of what women are told to put on their hair is a kitchen remedy that has never been near a fixed dose, and the other half is a tablet. Neither of those is the problem with the advice. The problem is the address."

She means it fairly literally.

"Swallow anything and it goes where the body decides to send it, which is more or less everywhere except the one square inch you care about. A follicle trying to push out a new hair in October needs what it needs delivered to the scalp, in the same amount, every day. Not grated into a cup and hoped over. Same ingredient. Different address."

Illustrative. The spray is worked along the parting onto the scalp, rather than through the lengths.

The caffeine is there to keep hairs in their growing phase for longer. The biotin is the same B vitamin as the tablets, except it's being put where the hair is actually made rather than sent through the stomach first.

The product is called HaloGrow. It's a spray rather than a tablet — for the reason Fiona gives above — and the two ingredients are printed on the carton. It's worked along the parting, morning and night, and it takes about as long as brushing your teeth.

TWELVE WEEKS, AT HER OWN SINK

Sheila started in the last week of October — which she now points out was about three weeks after the shed had begun.

Weeks one to two.Nothing visible. What she did notice was the plughole. "It went from a horror film to a normal amount. That was the first thing that made me keep going."

Illustrative. The way most women actually check a parting — the bathroom mirror and a phone.

Weeks three to six.Short, fine hairs standing up along the parting, the sort that won't lie flat. "My hairdresser spotted them before I did. She asked what I'd changed and I got embarrassed and said nothing."

Illustrative. Short new hairs along the parting at around six weeks. Individual results vary.

Week twelve.The parting itself. "It's the width of it. I can see it in photographs — which is where I could always see the problem, so it's where I look for the difference."

Illustrative. A narrowed parting at around twelve weeks. Individual results vary.

Fiona is measured about timelines. Twelve weeks, she says, is the earliest honest point at which anyone should judge anything they put on a scalp — because that's roughly the length of one cycle. Individual results vary, and a woman who has produced no new hair at all in a given patch for several years should expect less than a woman whose hair is thinning evenly.

THREE READER RESPONSES

Three illustrative reader responses on autumn shedding, lightly edited for length. Individual results vary.

THE THREE THINGS SHEILA ASKED FIRST

Before she ordered anything, Sheila asked three questions. They are, Fiona says, almost exactly the three questions every woman over sixty asks her, in the same order.

"Is it really worth it, at my age?"

Sheila answers this one herself — and she answers it with the car park.

"The course I didn't book was six hundred and forty pounds — and that was before the products they wanted to sell me at reception. This is a spray and two minutes at my own sink, morning and night. I'd have paid the ninety-five just to be told to go home and live with it. I'd rather have spent it on this."

Fiona's twelve weeks is the yardstick here, not a fortnight, so it's worth checking what the order page offers for that length of time before choosing. The current introductory price and UK delivery are shown there.

"Does it work on hair this thin, this late?"

"Late isn't the same as gone," Fiona says. "The question is only ever whether a follicle is idle or finished, and a follicle that shed a hair this autumn is by definition still running to a clock. That's the whole argument for doing something while the shed is still running instead of waiting until spring — when the same follicle has had five more months of nothing asked of it."

"Then why isn't it in Boots?"

It isn't — and the answer is dull rather than sinister. A shelf in a high-street chemist has to be paid for, and that cost lands on the price of whatever's standing on it. HaloGrow is sold direct by the people who make it, which is the reason an introductory price exists at all. It also means the maker's own page is the only place to get it.

✔Editor's Note.HaloGrow is currently running an introductory offer for readers, with free UK delivery. Fiona's yardstick is a full twelve-week cycle rather than a fortnight, so check what the order page offers for that length of time. Current prices are shown there.

See Today's Price And Delivery

Secure checkout. Free UK delivery on the introductory offer.

The autumn shed runs to the end of November. Fiona's twelve weeks start the day you start, not the day you decide.