HEADLINES that cheer are always welcome and “Vitamin A creams can reverse signs of ageing” was one for everyone who looks in the mirror and says: “Who is that wrinkly person?”

A study published in the Archives of Dermatology found that a lotion which contained a 0.4 per cent concentration of retinol (vitamin A) had a significant wrinkle reduction effect over six months. It was tested on people with an average age of 87. If retinol can do it for them, we mused, what can it achieve for people half that age?

The news came after another “it really works” cosmetic story. Women have been queuing at Boots for its Protect and Perfect beauty serum since favourable testing on the BBC Two programme Horizon. Superdrug has seen its sales of retinol cream treble this week.

So, is that it then? Has science really proved that cosmetic creams work? It is a little appreciated fact that the cosmetics industry, worth £6.4 billion in the UK alone, is built on science. Analytical chemists, formulation chemists, microbiologists and toxicologists are all essential to developing beauty products that do what they say, keep well and do no harm.

Basic research by the cosmetics companies on skin structure occupies legions more scientists. L’Oréal alone employs nearly 3,000, spending £350 million a year on research. If claims are made, manufacturers have to back them with science. It’s a different sort of proof from that required for pharmaceuticals – all the research on cosmetics is kept locked away from the public for commercial reasons – but it’s still proof of efficacy.

So perhaps we shouldn’t be so surprised when some independent research indicates that some of these products work. Equally, though, we have to keep our expectations in check. Proof of effect is different from saying that something will make you look young. The “before” and “after” difference may be greater in the optimistic user’s eye than an objective observer.

It reminds me of when I was seduced into buying a Wonderbra. “There seems to be a bit too much room in this one,” I said to the assistant. “It’s a Wonderbra, Madam, not a miracle worker,” she said briskly. The same can be said of beauty potions. There might be a deal of science behind them, but the effects are rarely dramatic and benefits take time to work.

So how should you assess competing claims? Well, as a scientist, I’d advise forgetting the science. Buy the products that have been on the market longest, that huge numbers have continued to use. It’s all the science you need to know.

Times recommends

• Tewkesbury: when the memories flood back
• How I lost the gift of joy for a while
• The A-Z of winter style rules