Eighteen soldiers face being kicked out of the army for using steroids to boost their performance on the battlefield.
The front line troops all belong to the 7th Parachute Regiment Royal Horse Artillery, in Colchester. Among them are two sergeant majors, it is understood.
Stringent new tests by the army saw the soldiers fall foul of new rules which were introduced in June, amid worries at the Ministry of Defence about the growing popularity of sports supplements.
The new tranche of tests can detect substances such as steroids and banned supplements. They expand on the traditional regime of testing for banned drugs such as heroin, cocaine and cannabis.
An army source told IBTimes UK the prohibited substances involved were steroids, which help build body mass quickly by enabling users to train for longer.
Steroids have long been banned in professional sports due to dangerous side-effects, such as increased aggression and kidney damage.
Army chiefs believe the impact steroids can have on mental health make them unsuitable for use by soldiers.
"It's widely recognised that taking steroids is not conducive to being in the army. It is not the case they were taking a sport supplement," said the army source.
"It is not necessary to take performance enhancing supplements to be in the army.
"There are lots of supplements which are completely legal and are fine to use. There are also a number which we do not believe are good for the mental health of recruits.
"We say if you choose to take them, you do it at your risk and you need to be responsible for what you are taking and could possibly fail a drugs test."
Soldiers face tough conditions during long tours of duty in tough conditions in places such as Afghanistan. For some, the temptation is there to do anything to hit the peak of performance.
Col Richard Kemp, a former commander of British forces in Afghanistan, said: "There is a strong culture of physical fitness in the army, and there has to be.
"When a soldier is serving, they are carrying extremely heavy weights across difficult terrain for a long time and they have got to be in good physical shape.
"It is an extremely important part of their lives and in some ways, it is admirable that many soldiers will go above and beyond to get themselves in very good physical shape, " he told the Telegraph.