While there is no shortage of collagen products

Type “collagen” into Google and you will receive a surprisingly varied set of results. Up pop sites selling powders, pills, face creams and drinks. It can be injected, ingested and even used as a sausage casing. It has also just become the star ingredient at a chic London restaurant. But what is the most abundant protein in the human body doing appearing all over the internet and on a must-have menu?

Some 30 per cent of all the protein in our body is made up of collagen, which forms strong sheets that support the structure of our skin, bones, cartilage and internal organs. It keeps our skin strong and elastic and its reduction is associated with ageing.

In the 1980s, collagen injections were introduced into the cosmetic surgery market and quickly became a popular way of making lips plumper.

But while other fillers and even implants have supplanted collagen’s popularity as the provider of a pert pout, the beauty industry – ever in search of elixirs of youth – has taken to using the stuff in ever more creative ways.

Bevis Man, spokesman for the British Skin Foundation, explains that: “During the natural course of ageing, collagen and elastic tissue within the dermis depletes, meaning the skin starts to sag and wrinkle. Loss of fat from the skin, coupled with years of facial movement, means the skin looks less plump and we get wrinkles that form around the eyes and forehead over time.”

So it’s unsurprising that collagen has attracted the attention of one of the biggest names in cosmetics. L’Oreal offers a Wrinkle Decrease Collagen range, including eye cream with collagen “biospheres” to combat bags under the eyes (selling at £11 for 15ml, approximately three teaspoonfuls), while a new face cream, also from L’Oreal, to be launched under the brand Vichy this April, claims to stimulate collagen production in our own skin. The LiftActiv Derm Source contains a plant sugar called Rhamnose, from the Brazilian plant Cat’s Claw, which its maker claims coaxes collagen cells to behave as they do in youthful skin.

But beyond the dressing table, collagen fans can now get their fix at the dinner table. The London restaurant Gilgamesh has just started offering a tasting menu based around the protein.

The menu, which includes delicious dumplings, seaweed salad, soup, sushi and ice cream –- all with added collagen – has been designed by chef Ian Pengelley. He is convinced that eating collagen “helps the skin”, and says he was inspired by the collagen craze in Japan, where “beauty” restaurants add the protein to meat, fish and vegetable hot pots; shops sell “collagen rich” noodles and dishes naturally high in collagen, such as chicken skin and shark fin, have increased in popularity. Pengelley, who says 90 per cent of diners trying the popular menu are women, gets £45 jars of powdered collagen made from fish bones sent over from Japan. He next hopes to create a collagen cocktail: a tiramisu-style dessert drink with added protein.

Those with a sweet tooth have also been targeted by companies that have experimented with sweets made from the stuff – “Eat Yourself Beautiful” collagen marshmallows went on sale in the UK in 2009, while late last year a Brazilian company announced it was to launch its no-sugar, collagen-infused “Beauty Candy”.

But does eating collagen, or slathering it on our faces, have any genuine effect on skin? Jonathan Hadgraft, emeritus professor of biophysical chemistry at the University of London, has been researching the area of skin penetration since the late 1960s and is sceptical.

“There seems to be a misconception in the beautyworld that 60 per cent of anything put on the skin is absorbed,” he says. “This is far from the truth. In reality, only a few per cent is absorbed. “The skin has evolved to be a very good barrier which is why we are not constantly poisoned by materials with which we come into contact.”

While nicotine permeates the skin effectively, with 30 per cent of a nicotine patch being absorbed in 24-hours, insulin – a larger molecule used for the treatment of diabetes, is unable to because of its size.

“Collagen is a large protein and a simple evaluation of its chemical properties suggests that it would not permeate unless it was forced through the skin using physical damage to the skin, for example, a needle,” he says.

Julie McManus, head of scientific affairs at L’Oréal, agrees that collagen in the Wrinkle Decrease range does not penetrate the skin. “This is a dehydrated form of collagen that inflates with the moisture on the skin, giving a plumped-up, smoothing effect.”

So just as foundation can only give a temporary illusion of a good complexion, this cream only creates a temporary youthful look.

In contrast, she says the active Rhamnose sugar in the Vichy cream “affects the activity of the cells that produce collagen in the dermis”.

As for eating collagen for dinner or as a sweet treat, registered dietician Anna Raymond remains unconvinced that this alone may have the potential to reverse any signs of ageing.

“It is an area that needs researching. And there may be a placebo effect: if people believe in it this may be enough for them to benefit.” She recommends a balanced diet and says that lean meats and eggs contain essential amino acids that stimulate collagen production in our bodies.

Kuniko Takahashi, a nutrition scientist at Gunma University in Japan, concurs. In her book Tabemono Joho Uso Honto, or Truth and Falsehood of Food Information, she writes: “Good protein contains sufficient amounts of all kinds of essential amino acids and most animal protein falls into this category. Collagen is no better than average as a protein.”

While there is no shortage of collagen products on the market, Man believes there is a better – and more cost effective – way of protecting the collagen in our skin. “If people are genuinely concerned about the appearance of their skin, the two simplest things to do are to give up smoking and to protect the skin from any (further) sun damage by using sunscreen,” he says. “Both speed up the breakdown of collagen, essentially meaning you look older than you really are.”