Some body builders are injecting themselves with a posing oil called Synthol, which acts like a silicone injection and causes their arms to puff up like Popeye's:

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… "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.

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(via We Make Money Not Art)

Update: Mark sez, "The bodybuilder in

you picture is Gregg Valentino. He

denies taking Synthol

in much the same way Lance Armstrong points out he has never tested

positive. Steroid abuse by American kids is on the increase, just as they are

doing less sport. Are they emulating celebrities? Stallone was

recently busted for having illegal Human Growth Hormone, while

Anna-Nicole Smith also took HGH.

Gene doping, meanwhile, is already with us."