Helen Mirren was probably right about moisturiser, so here’s an owner’s guide to looking after your skin

She knows her lines. PA/Mok

Cosmetics firms spend a fortune coming up with advertising slogans that stick, like L'Oreal’s “Because You’re worth it” campaign. And then, amid all the gloss, inevitably, a blemish appears.

For this particular company, one recent blemish appeared in the form of British actress Helen Mirren, one of the many well-known faces employed by the brand. Revealing her personal thoughts about the effectiveness of her moisturiser, the 72-year-old star of The Queen suggested that it “probably does fuck all”.

There followed much amusement (and no doubt executive level embarrassment). But was she right? What are we to make of the widely made suggestion that the right kind of skin creams can slow down the ageing process? It is a seductive line, but unfortunately the truth is not so simple.

Human skin is a wonderfully effective organ (and as the British comedian Spike Milligan reflected, it is very good at keeping our insides in). It is an excellent barrier – like a highly patrolled military zone which allows us to cope with incoming attacks from bacteria, toxic chemicals and the sun’s rays.

Moisture everywhere. Shutterstock

But skin is constantly under siege as we get older. From the outside, the greatest threat is UV damage. The youngest looking, least wrinkly skin on your body will be the parts that are never (or rarely) exposed to sunlight.

From the inside, the skin suffers most from the effects of smoking and poor nutrition.

So the ways to protect your skin would seem pretty obvious. The top tips are: avoid frying your skin in the sun, don’t smoke, and eat a diet that contains lots of fresh fruit and vegetables – foods which contain plenty of antioxidants, which help the skin in its lifelong battle against oxidative stress.

Next top tip? Don’t get older.

Unfortunately, this one is much harder to follow. But the wrinkles we see are in the deeper dermal layer of the skin where the connective tissues of collagen and elastin age in ways that we frankly can’t influence much. (Apart from helping them out by following tips one and two.)

Use more than this. Shutterstock

As women age, they lose oestrogens, which help maintain the collagen content of the dermis and the “plumpness” of the skin. The deeper dermal layer gradually becomes much thinner, collagen fibres become stiffer and cross-linked, and there is a loss of elastin fibres which provide a lot of the natural elasticity of skin. The same happens to men but more slowly than female skin post menopause.

Underneath the surface

So what can we do about it? And where do skin creams come in? The bottom line is that most skin creams don’t penetrate into the deep dermis where the damage is being done. But they can provide a useful extra barrier layer to help keep the upper surface of the skin better protected from drying out, and from attack by the sun.

A skin cream that protects your skin from the harmful effects of sunlight is a good idea for preventing skin ageing and skin cancers. Creams that contain vitamins that act as antioxidants to help mop up the sun induced free radicals are also a good idea to help reduce sun induced damage.

But most creams do not penetrate beyond the upper barrier layer of the skin and most of the damage that is going on is in the deep dermis.

So Dame Helen was probably right. The best things for your skin do not come in an expensive tube or pot. It’s a better idea to eat well, and avoid excessive sun exposure and cigarette smoke. Also, like Helen, smile lots.