Go easy on the wrinkle fix

The common-sense brigade was aghast when, aged just 20, Scarlett Johansson confessed: "I use anti-ageing products. It's difficult not to feel under pressure — everybody in Hollywood is so beautiful."

According to research, a third of women under the age of 25 are applying products meant for the over 40.

Unsuitable for youth

But some experts say not only are these women wasting their money on things they don't need but, horrifyingly, could be damaging their skin permanently.

For starters, creams designed for older skins can be heavy and, when applied to younger ones, cause problems, as Dr Susan Mayou, consultant dermatologist at London's Cadogan Clinic, explains.

"Eczema patients who use products that are too greasy often suffer from a condition called occlusive folliculitis — sweat cannot escape from behind clogged pores, causing itchy, red lumps. Teenagers using a heavy product could suffer from the same thing," she says.

While this sort of mild infection is temporary and can be cleared up with an over-the-counter topical antibiotic, it's when young women use creams that have high concentrations of ingredients such as retinoids (derivatives of retinol, a form of vitamin A) and AHAs (alpha hydoxy acid compounds such as glycolic acid and lactic acid) that the problems really start, according to dermatologist Dr Nick Lowe.

"These compounds are included in anti-ageing products because they break down the top layer of the skin, increasing the rate at which the skin renews itself," he explains.

In older skin, the benefits of inflicting deliberate damage to the outer layer of the skin outweigh the negatives, as it helps to speed up cell turnover, a process that slows with age, and evens out uneven skin tone. But with younger skin, which is less resilient, they corrupt the skin's natural water-retaining protective function. "Younger skin, especially that on the cheeks, can be sensitive and more prone to react badly to these active ingredients."

That can result in irritation — redness, itching, flaking and so on.

Serious consequences

"If these teenagers are lucky, when they stop using the cream, these symptoms go away. If they don't, they need to spend more money on creams to try and get their skin back to normal."

More worrying than simple irritation is the long-term damage that could result from uninformed use of retinoids and AHAs.

"Because these compounds damage the outer layer of the skin, they increase skin photosensitivity, leaving skin far more susceptible to sun damage," Dr Lowe explains.

"Anyone who uses a product that contains a significant concentration of these is advised to ensure they use sun protection every day. If you don't apply an SPF when using products such as these, not only are you more susceptible to sunburn but you can cause many of the problems you're trying to avoid — age spots, uneven pigmentation and wrinkles."

Dr Lowe says: "Don't use sunbeds, don't smoke and do use an SPF15 sunscreen every day that contains UVA protection. That's going to be more effective than using products meant for women three times your age."