We used to know what 40-something looked like. It meant short, neat hair, sensible clothes and the onset of middle-aged spread.
It meant less focus on yourself and more on those around you (whos going to be looking at you, anyway?), a time for slipping gradually into the cosy cardie of your middle years. “Forty, fat and frumpy” was the tag that women dreaded, not least because it was so often true.
Now, 40-something looks... different; none of the old rules seems to apply. Thanks to those Desperate Housewives, we've come to feel that tousled tresses aren't just for youngsters. Madonna, in her 40s, cavorts on screen in leotards that Lady Gaga would be proud of.
Forty-something mothers borrow their teenage daughters' skinny jeans, chunky ankle boots and jackets - they're trim enough, after all that Pilates. And no one bats an eyelid, not when their lithe-limbed, 40-plus role models Liz Hurley and Elle Macpherson are flaunting their just-as-perfect-as-ever bodies.
Botox and wrinkle-fillers, skin peels and SmartLipo - procedures that hadn't been invented a generation ago - are becoming the norm, to the extent that many women in their 40s appear peculiarly ageless.
And while '45-year-old mother of three', is still a loaded description, when you see it alongside a photograph of Yasmin Le Bon and her teenage daughters you realise the big 4-0 is no longer such a major stepping stone towards incapacity, irrelevance and old age.
'Forty is just a little step,' says Dr Nick Lowe, consultant dermatologist at the Cranley Clinic in London. 'If a woman comes to me in her 30s and takes my advice on looking after her skin, I can certainly keep her looking that way until her early 50s.'
That advice will include trying out non-invasive and non-surgical treatments; lasers and radio-frequency devices, as well as Botox and fillers, along with broad-spectrum sunscreen by day and prescription skin-repair creams by night.
The stigma of messing around with your face has vanished. This has been aided by the plethora of extreme makeover TV shows and an increasing desire among women with well-known and well-preserved faces to confess to having work done.
'If they say it's all down to yoga and face cream, they've normally done Botox and fillers,' said one industry source. 'If they're admitting to Botox, there's usually been an awful lot more than that going on.'
It's become hard to gauge how old women actually are. Celebrity nail technician Andrea Fulerton observes many famous faces close up.
'Women are looking after themselves so much better nowadays that they always look at least five years younger than they are and that goes for their hands, which used to be a real giveaway of age, as well as their faces,' she says.
But cosmetic work is a slippery slope. At first, it's just powder and paint - the clever use of the latest high-tech cosmetics, such as skin primers that gloss over flaws and light reflecting particles that make your pout look fuller.
Next, there's eyebrow- shaping, hair-dyeing and facials, possibly involving machines with electrical currents to liven up slackening muscles. So far, so acceptable. But then come needles delivering line-relaxing Botox or fillers that plump up shrinking lips, puff out cheeks or pad out hollows. It sounds scary. It is scary, but it's a transition that is becoming a lot easier to make. In future, it will be easier still, as the lines begin to blur between the treatment options.
Face creams will become more powerful and personalised. Already, you can have a cream tailored to match your precise skincare requirements. Bionova is a cult brand available at Harrods that prompts biologically active substances within the skin to trigger self-healing processes.
Then there are the prescription anti-ageing creams containing tretinoin, a derivative of Vitamin A, which so far has been the only thing clinically proven to reduce wrinkles. These creams will be prescribed more often as wised-up consumers demand them.
Technically, face creams are cosmetics, so should not make a physiological change to the skin. But there are two on the market (Olay's Pro-X, available only in the U.S. at present, and No 7's Protect & Perfect Intense, at Boots) that have been shown by stringent clinical tests to rejuvenate wrinkled skin in a way that could previously be achieved only by the prescription- only treatment tretinoin.
They work by boosting collagen production in the skin, while Olay Pro-X also increases cell turnover so that skin regenerates faster. Meanwhile, Clinique's Even Better Clinical Dark Spot Corrector, available at Selfridges from Friday, promises to brighten skin and minimise pigmentation marks. It has been shown to work as well as the standard dermatologist prescription treatment that uses 4 per cent hydroquinone, which whitens the skin.
Pro-X, just like L'Oreal's Youth Code, uses technology based on genomics - working out what has changed, in terms of the genes between young skin and old skin, then identifying ingredients to tackle those changes. Its potential is mind-boggling - once scientists have worked out which genes they need to tackle, they can find ways to activate the right 'youth' genes to, say, produce more collagen or reduce inflammation within the skin.
The menu of non-surgical treatments will expand as new technology develops, too. There will be machines that can use combined laser technology to tackle pigmentation and resurface skin at the same time. And face and body sculpting using stem cell-enhanced fat grafting will become more widespread.
NHS surgeons trialling this technique have been getting promising results in breast enhancement, while cosmetic surgeons in London have been using the same technique to revolumise sagging faces.
By next year, when the results of the NHS trials are published, you can expect far more women to be demanding these kinds of procedure, despite the £7,000 price tag (which is as much as for a traditional facelift). Surgical facial adjustment will become increasingly subtle as existing techniques are refined to give less discernible, though reliable, results, with less recovery time and scarring - keyhole forehead lifts and mid-facelifts are already available.
We will even be able to pop pills to return our hair to the colour of its youth. L'Oreal has been working on hair re-pigmentation technology for years and hopes to have the results on sale within a decade.
Most surgeons prefer to take a 'little and often' approach to facial rejuvenation, changing a face by degrees with a series of subtle tweaks rather than one hugely obvious lift. The British Association of Aesthetic Plastic Surgeons (BAAPS) recorded 36,400 procedures last year among members, a rise of 6.7 per cent from the previous year, despite the financial downturn.
'There is tremendous interest in cosmetic surgery,' says leading cosmetic and reconstructive surgeon Charles Nduka, who has commissioned a comprehensive survey of attitudes to cosmetic surgery among 5,000 women aged 16 to 60 for the not-for-profit website www.safercosmeticsurgery.co.uk.
'Around 7 per cent of the women questioned had already had a surgical procedure of some sort,' he says.
Another major reason why women are looking younger at 40 is a shift in our attitudes to ageing. Or perhaps that should be to growing up. There used to be a divide between the generations because women of a certain age surrendered to it.
Now, the middle-aged want to stay young, act young, think young. They gather friends on Facebook; they tweet. Along with their teenage daughters, they are addicted to Grazia and pore over the weekly charts of top new looks.
Pop into Topshop or American Apparel on a weekday morning, when all the lissome 15- year-olds are safely in their classrooms, and you might find their mothers trying on the clothes. Better health and healthy habits are another contributing factor.
Pilates, FitFlops and low GI are the staples of the 'are-you-really-40?' generation. They get their five-aday, 10,000 steps and eight hours of beauty sleep. And the savvy ones may also be getting their hormone levels checked out, too.
'Looking young is not just about Botox,' says Maria Somers, managing director of the HB Health clinic in Knightsbridge. 'What's the point of doing over the outside if you don't check what's going on on the inside?
'Your lifestyle has an enormous impact on how old you look. Making sure you have enough sleep, exercising and eating a well-balanced diet are important.'
So how will 40 look in 40 years time? That, I suspect, will depend on who you are, your personal values and how rich you are. If you can afford the work, and attitudes towards it continue to become more permissive, then, unless you insist on ageing gracefully, why not?
And in the future, if you can't afford any work, it's going to show, in the way that today in the U.S. the poor are marked out by their bad teeth. Barring a volte-face in attitudes, the pressure for women to look young for their age will increase.
Youth and beauty have always gone hand in hand. There is a generation of girls growing up who have learned to adopt skin-friendly habits. Any dermatologist will tell you that the lines that show up when you're 40 are the result of everyday exposure to daylight.
Many girls use sunscreen daily, avoid sunbeds and have never smoked. They've savvy about popping pills - high-dose fish oils and antioxidants - to maximise their skin health. They started on pre-emptive Botox and Vitamin A creams in their early 20s, not to freeze their faces, but just enough to prevent their lines of expression from becoming permanent features.
They don't lie on the beach on holiday. By the time they're 40, they will be laughing. They simply won't look as old as 40-year-olds do now. -- Daily Mail