The BBC's Nicola Carslaw: "Most women try out anti-ageing creams"

Many of the physical signs associated with old age are down to inherited genes, sun exposure and smoking, according to Professor Chris Griffiths of the University of Manchester.

A fellow dermatologist, Dr Nicholas Lowe, said that it was much more effective to apply sub block every day.

Doctors and scientists are examining the evidence at a conference run by the Royal Society of Medicine.

Fancy packs

Prof Griffiths dismisses many anti-ageing remedies, saying they offer the buyer little more than expensive packaging.

He agrees that sunscreens with a protection factor of greater than 15 can prevent - and maybe even reverse - signs of old age. But he stresses that the sunscreens must be used properly.

He also says retinoic acid - available only on prescription - will repair and smooth the skin and reduce wrinkles.

Dr Lowe said a small number of cosmetic creams had some effect in repairing damage to the skin, but it was more important to take daily action to protect against the ageing effects of the sun's ultraviolet rays.

"The main message with creams is that if they contain an efficient sunscreen and you use it every morning then you are going to halt some of those ageing changes," he told the BBC.

The BBC's Roxanne Panthaki looks at the UK's obsession with youth

"The skin has a certain ability to repair itself when it is protected but these creams only have a modest benefit."

While genetic factors played some part in the overall ageing process, lifestyle had a much greater impact on appearance - particularly the face, he said.

"About 30% of facial ageing is genetic and a lot of the rest of the percentage is repetitive sunlight, smoking and other hazardous things we expose ourselves to," he said.

Real psychological effect

While some may dismiss excessive concern with appearance and ageing as harmless vanity, psychologists point out that looking old can cause serious mental distress.

Dr Nicholas Lowe: Lifestyle is important

Surveys show that many of the people who undergo plastic surgery to reverse appearance of ageing do so because they fear they will lose their job if they look old.

Consultant psychologist Dr Eileen Bradbury said: "We are very fixed on the idea that youth is connected to not just beauty but to being powerful, being strong, healthy, energetic, having the best jobs and having the most money."

About 35% of people aged 50 to 64 have no job - a much higher rate than many other European countries.

BBC Breakfast News discusses the issues with Dr Eileen Bradbury and Dr Nicholas Lowe

The government is so concerned that people face discrimination because of their older appearance that it has launched an Action on Age programme.

It aims to persuade employers that discriminating on the basis of age makes bad business sense.

The Royal Society of Medicine conference will hear that the cosmetics industry plays a vital role in putting health messages across, and employs dedicated scientists who carry out cutting-edge research on anti-ageing.