Shocking impact of smoking on twins' face shown in comparison to non-smoker twins

The impact that smoking can have on a person's face has been revealed in a fascinating study on twins in the US.

Long gone are the days of the 1970s and 80s, when lighting up and puffing on a cigarette was actively promoted by countries around the world, because it turns out that inhaling a load of smoke and chemicals into your lungs isn't actually that healthy.

After decades of researchers pouring their time and money into the impact of smoking, we're now aware that puffing on a stick of tobacco wrecks havoc on our bodies, with numerous studies linking the highly addictive pastime to an increased risk of strokes, heart disease, and cancer.

However, it can be difficult to fully envision the damage taking place inside of your body, which is what makes one study from the US particularly interesting.

The effects of smoking show on your inside and outside (Getty Stock Images)

Researchers from the Department of Plastic Surgery at Case Western Reserve University examined photos of twins taken at an annual gathering of twins in Twinsburg, Ohio.

Participants - aged between 18 and 78 - had their photos taken and were then split into two groups.

One group contained 45 pairs of twins in which only one person had smoked while the other group included twins which had both smoked, but with one sibling who'd smoked at least five years longer than the other.

The images were then assessed by two doctors and a medical students – and the results were striking.

The twin on the left had smoked for more than 20 years longer than her sister (American Society of Plastic Surgeons)

Researchers then ranked their facial features on a four-point scale, concluding that smoking accelerates aging.

"This study confirms some of what was believed in the most scientific way possible," Dr. Bahman Guyuron, who led the research, explained to CNN.

According to the results, the smoking twins scored worse for wrinkles around the lips, jowls and upper eyelid skin redundancy.

The twin on the left here is a non-smoker (American Society of Plastic Surgeons)

"Smoking reduces the collagen formation, results in collagen degradation and reduces the skin circulation," he continued.

"Additionally, nicotine reduces the skin thickness. All of these reduce skin elasticity and (cause) premature aging."

Guyuron also pointed out something he described as 'festoons of loose skin' underneath the eyes of one of the smoking twins, adding: "When I see that [on patients], I don’t have to ask if they smoke. I know they do."

Both men were smokers, however the right-hand twin smoked for 14 years longer (American Society of Plastic Surgeons)

However, Guyuron did note that while the study did take into account factors such as alcohol consumption, usage of sun protection and stress levels, diet and environment were not examined.

If you're curious to understand more about what smoking is doing to the inside of your body, a simulation recently revealed what happens to the lungs every-time you inhale a cigarette, from scars to your lung tissue and damage to the fine hair-like structures known as cilia.