Elle Macpherson is telling an audience of women at Selfridges, London, what it feels like to struggle with a muffin top, fatigue and finding herself so irritable she shouted at the kids.

The big difference between Macpherson and the rest of us who accept being sleep-starved and stroppy is that, in true celebrity style, she countered her slump two years ago by creating her own sellable solution, an "alkalising greens" food supplement.

"I just wasn't feeling my super-self and I'd lost the spark which keeps you feeling energised and motivated," she said at the launch of her Super Elixir in the London store.

"My skin was dry, I was gaining weight around my waist, feeling moody and my joints ached.


"I put it down to ageing but then I thought, I don't like that feeling it, whatever the cause, and knew things had to change. So I got help with nutrition, threw out the ton of tablets I'd been taking daily, and helped create this brilliant alkalising supplement instead."

Without a hint of irony, she describes it as "my birthday present to women".

Even so, the model, who turned 50 in March, still has to deal with ageing.

"Do I look back to how I looked in my 20s? Yeah, just like most women do and I think, 'Wow, did I really look like that?' At the time I didn't realise I was that big a deal and wasn't so confident, even though I pretended to be so cool.

"I feel better now than I've ever felt because I'm older, wiser and truly believe that being strong, inspired and capable is as important as our body shape.

"That's why I truly didn't have a problem with becoming 50, and I wanted to go into it with grace rather than fighting it. At this age, of course, you have to make more effort and being fit and being healthy from the inside is really important - if things are good on the inside, it shows on the outside.

"I just think women today want to look good at whatever age and realise it's pointless chasing after youth."

Her own youth was certainly charmed. She opted for modelling from the age of 17 rather than studying law and survived the demands of the often brutal fashion industry as well as high-octane, jet-setting and partying as her success grew through the 1980s.

"I have certainly gone through periods in my life where I haven't treated myself kindly," she says drily.

"I grew up young. I've done everything, I'm no angel and haven't led a sheltered life. In a sense I've experienced everything, partying with Andy Warhol, going to New York's Studio 54, and meeting Michael Jackson and Diana Ross.

"I think I survived thanks to the values instilled in me as a child - a strong sense of family, commitment to what I love, self-discipline and a desire to methodically work through problems."

She adorned the much-coveted cover of Sports Illustrated a record five times, and, in 1986, Time Magazine put her on its cover and dubbed her "The Body".

"I thought, great moniker, brilliant for business - I'll use that, thanks," she says.

It's the name of her hugely successful brand and her lingerie range, Elle Macpherson Intimates, is sold globally.

She's also hosted - and been an executive producer for - fashion reality shows in America and is well recognised in the UK, which she's made her home, as a judge on Britain & Ireland's Next Top Model.

She has two sons, Flynn, 17, and Cy, 10, from her nine-year relationship with financier Arpad Busson, and wed billionaire, Jeffrey Soffer, a father-of-three, in 2013. Although she was married in her 20s to a man two decades her senior, Gilles Bensimon, a former creative director of Elle magazine, she admits she never thought she would marry again.

"I've never put much importance on it, but then the love of my life asked me to marry him and I didn't hesitate," she says, as she talks of the romance that broke up a few years after they got together but was rekindled when he narrowly survived a helicopter crash in the Bahamas.

Her anti-ageing tip is drinking three litres of water a day, and staying active - she's a keen skier and off-road cyclist.

"I don't like the word exercise - it sounds like a punishment. I prefer to say activity. Just 45 minutes a day is good and it can just be a walk. It doesn't have to be a gym session."