From expensive face creams to invasive procedures, some people will try just about anything to look younger. 

But a study now suggests if you really want your skin to appear wrinkle-free, you should be focusing on your hair. 

Scientists from Franklin and Marshall College in Pennsylvania set out to understand how the colour of your hair affects the appearance of your skin. 

The team showed participants pairs of photos of women, in which their hair had been adjusted. 

When asked to rate the evenness of the women's skin, the results revealed a clear pattern. 

The faces presented with darker hair were rated as having more even skin than those with lighter hair. 

The findings will come as bad news to the increasing number of Britons who are embracing their grey hair. 

'This is an important finding given that skin smoothness influences evaluations of trustworthiness, competence, attractiveness, and health, and these evaluations influence various perceptions and real-world outcomes,' the researchers said. 

Previous studies have shown the appearance of your skin plays an important role in the perception of your age, health and attractiveness. 

However how your hair influences these perceptions has remained unclear until now. 

To get to the bottom of it, the researchers carried out two experiments. 

In the first experiment, the team took photos of the faces of 45 women aged 19 to 79, before surrounding them with either a black or skin-coloured oval. 

Sixty-one participants were then asked to rate the evenness of their skin in both photos. 

The results revealed the skin on the faces with the black background was perceived as more even than the skin on the faces on the skin-coloured oval – even though the faces themselves were left completely untouched. 

In the second experiment, the researchers took photos of 41 women, before adjusting the colour of the hair, and asking 80 participants to rate their skin. 

Again, the results revealed that the women's skin was rated as smoother when they had darker hair.

Dr Carlota Batres, who led the study, said: 'These results show that skin appearance is affected by contrast between the skin and surfaces that surround the face, whether it be background color or hair color.' 

The news comes shortly after scientists from Nagoya University in Japan uncovered a simple way to prevent greying.

The researchers found that an antioxidant called luteolin appears to stop the greying process in mice. 

And while it's yet to be tested in humans, the scientists believe it could have a similar effect.  

Best of all, the antioxidant can be found in several common vegetables, including celery, broccoli, carrots, onions and peppers. 

'This result was surprising,' said Professor Masashi Kato, lead author of the study. 

'This finding suggests that luteolin may have a unique medicinal effect that prevents greying.'