Identical twins reveal startling changes to their faces after one of them smoked and the other didn't

Two pairs of identical twins have revealed the stark impact smoking can have on your face and skin as a doctor breaks down exactly what happens biologically.

A pair of identical twins, alike in DNA, but different in the habitual practice of smoking.

A scientific study looking into the impact of smoking on not only one's body but one's appearance and skin and used identical twins as a way to assess the damaging effects.

The study - published in Pub Med - took several sets of twins and looked at the effects of smoking alongside sun exposure on the skin, investigating what happens when one twin takes part in the activities and the other doesn't.

One pair of twins to take part in the study was Barb and Brenda. For at least 14 years, Brenda smoked half-a-packet of cigarettes every day. And for 30 years, had approximately 14 hours of sun exposure per week for eight to 10 weeks of the year.

In contrast, Barb had never smoked and had just two hours of sun exposure a week -seven times less than her sister.

Brenda (left) and Barb (right) (American Society of Plastic Surgeons / Dr. Bahman Guyuron)

As you can see from the images, the differences between the twins' appearances are pretty stark.

While there's certainly nothing wrong with wrinkles, Brenda's skin features a lot more prominent lines than Barb and her skin has a greyish tinge to its tone.

Dr. Bahman Guyuron, a plastic surgeon who led the study, pointed out to CNN what he described as 'festoons of loose skin' under Brenda's eyes, which he said were attributable to her smoking.

Is it time to put down the packet for the sake of your skin? (Getty Stock Images)

“When I see that [on patients], I don’t have to ask if they smoke. I know they do," he said.

Rubbing it in slightly, Barb noted she 'love[d] being called the younger one' between her and her sister.

Other impacts of smoking and sun exposure were demonstrated in the study by twins Jeanne and Susan, with Jeanne claiming that her sister looked '10 years older'.

Researchers went slightly further, however, claiming Susan looked 11 and a quarter years older than Jeanne.

Her advanced ageing was attributed to the fact she'd smoked for 16 years of her life, as well as spending as much time as she could in the sun.

Meanwhile, Jeanne was careful to have 'as little exposure as possible'.

Discussing the differences between the twins, Guyuron pointed to Susan’s dark, patchy discoloration and age spots.

Jeanne (left) and Susan (right) (American Society of Plastic Surgeons / Dr. Bahman Guyuron)

He also noted how UV light from sun exposure can reduce skin’s elasticity, increase wrinkles and deepen creases.

He reflected: "This study confirms some of what was believed in the most scientific way possible. Among twins with greater than five years’ difference in smoking duration, twins who had smoked longer had worse scores for lower lid bags, malar bags, and lower lip vermillion wrinkles."

Essentially, the doctor explained smoking 'reduces collagen formation' and 'reduces the skin thickness' which reduces 'skin elasticity' and prompts 'premature ageing'.

Well, maybe it's time to look in the mirror and admit no matter how many steps your skincare routine is, it's certainly not going to work miracles if you keep smoking.