Synthol - the substance, produced by various companies but known colloquially as synthol, binds with the muscle fibres creating a freakish, bloated appearance. Without any weight training, recipients of the injections can end up with arms larger than their legs.
Synthol is said to be attracting the interest of British gym-goers looking for instant “bulk” and unconcerned about any associated health risks.
Synthol, which is a mixture of triglyceride oils and benzyl alcohol, was originally intended as a form of “posing oil” for bodybuilders. When injected into a muscle, however, the body is slow to break it down, so giving an inflated appearance.
McVeigh, who called its use “daft”, said: “It doesn’t actually develop the muscles as such; it just sort of sits in the tissues and makes them larger.
“One of the main problems people have with this is deformity as gravity plays its part, giving you droops within your muscles. There are some terrible cases of inflamed tissue from it.
“Also, because it gives a fast swelling, you will get cramp from a squashing of the nerve. Then you can get crushing of the actual blood vessels and blood flow cut-off.” Some authorities in the US have said bodybuilders also risk giving themselves a pulmonary embolism, which can be fatal, by injecting synthol directly into a major blood vessel.