But it can lead to

does not enhance strength but makes men appear more muscular

This gruesome video reveals a man having litres of oil drained from his arm after he injected himself with the substance in order to look more muscular.

Bodybuilders over the world are risking death by carrying out the practice, in which they inject themselves with a potentially lethal cocktail of oil and alcohol to pump up their muscles.

The injections do not enhance the strength of muscles, they simply swell and enlarge them, leading to a 'bulked up' look.

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The gruesome video shows a doctor injecting the man's red and swollen bicep (left) before green mineral oil which has become infected gushes out for several minutes as he screams in pain (right)

Mainly people inject themselves with mineral oil, which is similar to baby oil but unscented, and smaller amounts of alcohol and anaesthetic.

The substance, called Synthol according to bodybuilding blogs on the internet, contains oil, a painkiller and alcohol to sterilize the mixture.

But doctors warn the craze, which is popular in Brazil where the video was shot, as well as other countries in South America, also leads to infections, abscesses and cysts developing in the muscles.

These can grow and spread within the tissue.

Some users, when operated on, have been found to have arms full of pus and oil.

Others have had their arms amputated and some have even died due to the practice.

In the video, a man is seen lying on his back in hospital with his right bicep red and swollen.

He then screams and moaning in pain, as a doctor injects his arm with a needle.

Immediately, green fluid bursts out of the wound and flows over the white hospital sheet.

The man is seen screaming and groaning in pain as the liquid pours out.

Arlindo de Souza has grown 29in biceps - the biggest in Brazil - after injecting them with oil and alcohol

The injections can cause dangerous infections. Some users have had their arms amputated. Others have died

For several minutes the fluid gushes out until eventually blood begins to flow from the hole.

The man continues to groan as the doctor cleans the wound.

In March MailOnline reported on the story of Arlindo de Souza, a Brazilian bodybuilder who has grown 29in biceps – the biggest in the country – after the injecting the filler into his body.

Since beginning to inject his arms two years ago, he has already lost a friend to the practice.

He said: 'My friend Paulinho, he passed away from doing these things,' said Mr de Souza. 'I felt his death a lot. He took it, I took it, but he went beyond the limit. I advise no-one to take this oil.

'I've stopped taking it, and other things as well, but there is always that will to start again. But I'm managing to control myself, to this day.'

Mr de Souza said the oil can easily be bought online or under-the-counter at rogue pharmacies.

He has fears for his own health and has visited a clinic for help. But medics have so far refused to operate because 'he did it to himself'.